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Importance: An accurate prognosis is especially pertinent in mild cognitive impairment (MCI), when individuals experience considerable uncertainty about future progression., Objective: To evaluate the prognostic value of tau positron emission tomography (PET) to predict clinical progression from MCI to dementia., Design, Setting, and Participants: This was a multicenter cohort study with external validation and a mean (SD) follow-up of 2.0 (1.1) years. Data were collected from centers in South Korea, Sweden, the US, and Switzerland from June 2014 to January 2024. Participant data were retrospectively collected and inclusion criteria were a baseline clinical diagnosis of MCI; longitudinal clinical follow-up; a Mini-Mental State Examination (MMSE) score greater than 22; and available tau PET, amyloid-β (Aβ) PET, and magnetic resonance imaging (MRI) scan less than 1 year from diagnosis. A total of 448 eligible individuals with MCI were included (331 in the discovery cohort and 117 in the validation cohort). None of these participants were excluded over the course of the study., Exposures: Tau PET, Aβ PET, and MRI., Main Outcomes and Measures: Positive results on tau PET (temporal meta-region of interest), Aβ PET (global; expressed in the standardized metric Centiloids), and MRI (Alzheimer disease [AD] signature region) was assessed using quantitative thresholds and visual reads. Clinical progression from MCI to all-cause dementia (regardless of suspected etiology) or to AD dementia (AD as suspected etiology) served as the primary outcomes. The primary analyses were receiver operating characteristics., Results: In the discovery cohort, the mean (SD) age was 70.9 (8.5) years, 191 (58%) were male, the mean (SD) MMSE score was 27.1 (1.9), and 110 individuals with MCI (33%) converted to dementia (71 to AD dementia). Only the model with tau PET predicted all-cause dementia (area under the receiver operating characteristic curve [AUC], 0.75; 95% CI, 0.70-0.80) better than a base model including age, sex, education, and MMSE score (AUC, 0.71; 95% CI, 0.65-0.77; P = .02), while the models assessing the other neuroimaging markers did not improve prediction. In the validation cohort, tau PET replicated in predicting all-cause dementia. Compared to the base model (AUC, 0.75; 95% CI, 0.69-0.82), prediction of AD dementia in the discovery cohort was significantly improved by including tau PET (AUC, 0.84; 95% CI, 0.79-0.89; P < .001), tau PET visual read (AUC, 0.83; 95% CI, 0.78-0.88; P = .001), and Aβ PET Centiloids (AUC, 0.83; 95% CI, 0.78-0.88; P = .03). In the validation cohort, only the tau PET and the tau PET visual reads replicated in predicting AD dementia., Conclusions and Relevance: In this study, tau-PET showed the best performance as a stand-alone marker to predict progression to dementia among individuals with MCI. This suggests that, for prognostic purposes in MCI, a tau PET scan may be the best currently available neuroimaging marker.

Introduction: Tau is a key pathology in chronic traumatic encephalopathy (CTE). Here, we report our findings in tau positron emission tomography (PET) measurements from the DIAGNOSE CTE Research Project., Method: We compare flortaucipir PET measures from 104 former professional players (PRO), 58 former college football players (COL), and 56 same-age men without exposure to repetitive head impacts (RHI) or traumatic brain injury (unexposed [UE]); characterize their associations with RHI exposure; and compare players who did or did not meet diagnostic criteria for traumatic encephalopathy syndrome (TES)., Results: Significantly elevated flortaucipir uptake was observed in former football players (PRO+COL) in prespecified regions (p < 0.05). Association between regional flortaucipir uptake and estimated cumulative head impact exposure was only observed in the superior frontal region in former players over 60 years old. Flortaucipir PET was not able to differentiate TES groups., Discussion: Additional studies are needed to further understand tau pathology in CTE and other individuals with a history of RHI., (© 2023 The Authors. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)

Background: In Alzheimer's disease (AD) research, subjective reports of cognitive and functional decline from participant-study partner dyads is an efficient method of assessing cognitive impairment and clinical progression., Methods: Demographics and subjective cognitive/functional decline (Everyday Cognition Scale [ECog]) scores from dyads enrolled in the Brain Health Registry (BHR) Study Partner Portal were analyzed. Associations between dyad characteristics and both ECog scores and study engagement were investigated., Results: A total of 10,494 BHR participants (mean age = 66.9 ± 12.16 standard deviations, 67.4% female) have enrolled study partners (mean age = 64.3 ± 14.3 standard deviations, 49.3% female), including 8987 dyads with a participant 55 years of age or older. Older and more educated study partners were more likely to complete tasks and return for follow-up. Twenty-five percent to 27% of older adult participants had self and study partner-report ECog scores indicating a possible cognitive impairment., Discussion: The BHR Study Partner Portal is a unique digital tool for capturing dyadic data, with high impact applications in the clinical neuroscience and AD fields. Highlights The Brain Health Registry (BHR) Study Partner Portal is a novel, digital platform of >10,000 dyads. Collection of dyadic online subjective cognitive and functional data is feasible. The portal has good usability as evidenced by positive study partner feedback. The portal is a potential scalable strategy for cognitive impairment screening in older adults., (© 2023 The Authors. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)

Introduction: We comprehensively evaluated how self- and informant-reported neuropsychiatric symptoms (NPS) were differentially associated with cerebral amyloid-beta (Aβ) PET levels in older adults without dementia., Methods: Two hundred and twenty-one participants (48% female, age = 73.4 years ± 8.4, Clinical Dementia Rating = 0 [n = 184] or 0.5 [n = 37]) underwent an Aβ-PET scan (florbetapir or PIB), comprehensive neuropsychological testing, and self-reported (Geriatric Depression Scale - 30 item [GDS-30]) and informant-reported interview (Neuropsychiatric Inventory Questionnaire [NPI-Q]) of NPS. Cerebral Aβ burden was quantified using centiloids (CL). NPI-Q and GDS-30 queried the presence of NPS within 4 subdomains and 6 subscales, respectively. Regression models examined the relationship between NPS and Aβ-PET CL., Results: Both higher self- and informant-reported NPS were associated with higher Aβ burden. Among specific NPI-Q subdomains, informant-reported changes in depression, anxiety, and irritability were all associated with higher Aβ-PET. Similarly, self-reported (GDS-30) subscales of depression, apathy, anxiety, and cognitive concern were associated with higher Aβ-PET. When simultaneously entered, only self-reported cognitive concern was associated with Aβ-PET in the GDS-30 model, while both informant-reported anxiety and depression were associated with Aβ-PET in the NPI-Q model. Clinical status moderated the association between self-reported NPS and Aβ-PET such that the positive relationship between self-perceived NPS and Aβ burden strengthened with increasing functional difficulties., Conclusions: In a cohort of older adults without dementia, both self- and informant-reported measures of global NPS, particularly patient-reported cognitive concerns and informant-reported anxiety and depression, corresponded with cerebral Aβ burden. NPS may appear early in the prodromal disease state and relate to initial AD proteinopathy burden, a relationship further exaggerated in those with greater clinical severity., (© 2024 S. Karger AG, Basel.)

Introduction: We compared white matter hyperintensities (WMHs) in early-onset Alzheimer's disease (EOAD) with cognitively normal (CN) and early-onset amyloid-negative cognitively impaired (EOnonAD) groups in the Longitudinal Early-Onset Alzheimer's Disease Study., Methods: We investigated the role of increased WMH in cognition and amyloid and tau burden. We compared WMH burden of 205 EOAD, 68 EOnonAD, and 89 CN participants in lobar regions using t-tests and analyses of covariance. Linear regression analyses were used to investigate the association between WMH and cognitive impairment and that between amyloid and tau burden., Results: EOAD showed greater WMHs compared with CN and EOnonAD participants across all regions with no significant differences between CN and EOnonAD groups. Greater WMHs were associated with worse cognition. Tau burden was positively associated with WMH burden in the EOAD group., Discussion: EOAD consistently showed higher WMH volumes. Overall, greater WMHs were associated with worse cognition and higher tau burden in EOAD., Highlights: This study represents a comprehensive characterization of WMHs in sporadic EOAD. WMH volumes are associated with tau burden from positron emission tomography (PET) in EOAD, suggesting WMHs are correlated with increasing burden of AD. Greater WMH volumes are associated with worse performance on global cognitive tests. EOAD participants have higher WMH volumes compared with CN and early-onset amyloid-negative cognitively impaired (EOnonAD) groups across all brain regions., (© 2023 the Alzheimer's Association.)

On September 25 and 26, 2021, the Alzheimer's Association hosted the first meeting focused on people with early-onset Alzheimer's disease (EOAD)-sometimes referred to as younger onset Alzheimer's disease (AD). Though a diagnosis of AD can be devastating at any age, those with a younger onset-defined as symptoms developing prior to 65 years of age-face unique challenges. EOAD occurs when people are in the prime of their lives, often with multiple responsibilities including careers, community activities, and raising children and caring for older family members. These challenges warrant special consideration and study, yet people with EOAD are often excluded from AD research because of their atypical age of onset. To help fill this gap, we designed and launched the Longitudinal Early-Onset Alzheimer's Disease Study (LEADS) to enroll and follow 500 people with EOAD from > 15 sites in the United States, which the National Institute on Aging funded in 2018. The September 2021 meeting was designed to inform people with EOAD and their family members and caregivers about the latest research on the biology of EOAD, treatments in the pipeline, practical considerations about legal and financial arrangements for families, and the support networks available to them. More than 217 registrants attended., (© 2023 the Alzheimer's Association.)

Introduction: Delay in diagnosis of posterior cortical atrophy (PCA) syndrome is common, and the lack of familiarity with assessment tools for identifying visual cortical dysfunction is a contributing factor. We propose recommendations for the approach to the evaluation of PCA clinical features during the office visit, the neuropsychological evaluation, and the research setting. A recommended screening battery for eye clinics is also proposed., Methods: Recommendations were developed using results from a web-based survey of members of Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment (ISTAART) Atypical Alzheimer's Disease Professional Interest Area (PIA), literature review, and consensus by the PCA assessment working party of the Atypical Alzheimer's Disease PIA., Results: Survey results revealed robust agreement for assessment tool preferences for PCA features, and many respondents indicated that they reserve assessment tools for use only when PCA is suspected. For some PCA features, curated tools were preferred over validated battery tools, particularly for the office visit. Consensus recommendations superseded survey preferences for two core cognitive features within the 2017 PCA diagnostic criteria., Discussion: These consensus recommendations provide an evaluation framework for PCA clinical features and can facilitate timely and accurate recognition and diagnosis of PCA. Broader use of these tools should be sought, and development and validation of novel PCA clinical outcome assessments are needed to improve our understanding of atypical AD and other dementias and support the inclusion of those with PCA in treatment trials., Competing Interests: V.S.P.: Research is supported by National Institutes of Health (NIH), the John and Joanne Hare Fund for Accelerating PCA Research, University of Colorado Alzheimer's and Cognition Center, the North American Neuro‐ophthalmology Society, and Institutional support from the Lewy Body Dementia Association; also received support from the American Academy of Neurology for editorial work, royalties from Up‐to‐Date, Inc., the Alzheimer's Association for the Longitudinal Early‐Onset Alzheimer's Disease Study Patient Advocacy Committee, and Biogen and Eisai. B.F.B.: Honorarium for the Tau Consortium. Institutional research grant support: Alector, Biogen, Transposon, Cognition Therapeutics, GE Healthcare; Institutional NIH grant support: P30 AG062677, U19 AG063911, R01 AG038791, U01 NS100620, U19 AG071754, U24 AG056270. Institutional foundation support: Lewy Body Dementia Association, American Brain Foundation. Institutional philanthropic support: Mayo Clinic Dorothy and Harry T. Mangurian Jr. Lewy Body Dementia Program, the Little Family Foundation, the Ted Turner and Family Functional Genomics Program. G.R.: Research support from NIH, Alzheimer's Association, American College of Radiology, Rainwater Charitable Foundation, Avid Radiopharmaceuticals, GE Healthcare, Genentech, Life Molecular Imaging. In the last 36 months, he has served as a paid consultant on scientific advisory boards for Alector, Eli Lilly, Roche, Genentech, GE Healthcare, Merck, and as a paid member of Data and Safety Monitoring Board for Johnson & Johnson. He is an Associate Editor for JAMA Neurology. R.A.T.: Honoraria as an advisory board member from C2N Diagnostics. G.S.D.: Research is supported by NIH (K23AG064029, U01AG057195, U19AG032438), the Alzheimer's Association, and Chan Zuckerberg Initiative. He serves as a consultant for Parabon Nanolabs Inc, as a Topic Editor (Dementia) for DynaMed (EBSCO), and as the Clinical Director of the Anti‐NMDA Receptor Encephalitis Foundation (Inc, Canada; uncompensated). He is the co‐Project PI for a clinical trial in anti‐NMDAR encephalitis, which receives support from Horizon Pharmaceuticals. He has developed educational materials for PeerView Media, Inc., and Continuing Education Inc. He owns stock in ANI Pharmaceuticals. Dr. Day's institution has received support from Eli Lilly for Dr. Day's development and participation in an educational event promoting early diagnosis of symptomatic Alzheimer's disease. B.D.C.B.: Receives funding from Alzheimer Nederland (#WE.15‐2019‐13, #WE.03‐2021‐15). C.U.O.: Research support from Alector, Transposon, and Denali, and consulting work from Acadia, Reata—consulting. H.S.: Full‐time employee of the Alzheimer's Association and spouse employed by Abbott Laboratories. K.Y. is an Etherington PCA Senior Research Fellow and is funded by the Alzheimer's Society, grant number 453 (AS‐JF‐18‐003) and a NIH grant (R01EY027964), and reports support from Roche outside the submitted work. All other authors report no conflict‐of‐interest disclosures. Author disclosures are available in the Supporting Information., (© 2023 The Authors. Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring published by Wiley Periodicals, LLC on behalf of Alzheimer's Association.)

Introduction: Sleep-wake disturbances are a prominent feature of Alzheimer's disease (AD). Atypical (non-amnestic) AD syndromes have different patterns of cortical vulnerability to AD. We hypothesized that atypical AD also shows differential vulnerability in subcortical nuclei that will manifest as different patterns of sleep dysfunction., Methods: Overnight electroencephalography monitoring was performed on 48 subjects, including 15 amnestic, 19 atypical AD, and 14 controls. AD was defined based on neuropathological or biomarker confirmation. We compared sleep architecture by visual scoring and spectral power analysis in each group., Results: Overall, AD cases showed increased sleep fragmentation and N1 sleep compared to controls. Compared to atypical AD groups, typical AD showed worse N3 sleep dysfunction and relatively preserved rapid eye movement (REM) sleep., Discussion: Results suggest differing effects of amnestic and atypical AD variants on slow wave versus REM sleep, respectively, corroborating the hypothesis of differential selective vulnerability patterns of the subcortical nuclei within variants. Optimal symptomatic treatment for sleep dysfunction in clinical phenotypes may differ., Highlights: Alzheimer's disease (AD) variants show distinct patterns of sleep impairment. Amnestic/typical AD has worse N3 slow wave sleep (SWS) impairment compared to atypical AD. Atypical AD shows more rapid eye movement deficits than typical AD. Selective vulnerability patterns in subcortical areas may underlie sleep differences. Relatively preserved SWS may explain better memory scores in atypical versus typical AD., (© 2023 the Alzheimer's Association.)

The logopenic variant of primary progressive aphasia (lvPPA) is a neurodegenerative syndrome characterized linguistically by gradual loss of repetition and naming skills resulting from left posterior temporal and inferior parietal atrophy. Here, we sought to identify which specific cortical loci are initially targeted by the disease (epicenters) and investigate whether atrophy spreads through predetermined networks. First, we used cross-sectional structural MRI data from individuals with lvPPA to define putative disease epicenters using a surface-based approach paired with an anatomically fine-grained parcellation of the cortical surface (i.e., HCP-MMP1.0 atlas). Second, we combined cross-sectional functional MRI data from healthy controls and longitudinal structural MRI data from individuals with lvPPA to derive the epicenter-seeded resting-state networks most relevant to lvPPA symptomatology and ascertain whether functional connectivity in these networks predicts longitudinal atrophy spread in lvPPA. Our results show that two partially distinct brain networks anchored to the left anterior angular and posterior superior temporal gyri epicenters were preferentially associated with sentence repetition and naming skills in lvPPA. Critically, the strength of connectivity within these two networks in the neurologically-intact brain significantly predicted longitudinal atrophy progression in lvPPA. Taken together, our findings indicate that atrophy progression in lvPPA, starting from inferior parietal and temporoparietal junction regions, predominantly follows at least two partially nonoverlapping pathways, which may influence the heterogeneity in clinical presentation and prognosis., (© 2023 The Authors. Human Brain Mapping published by Wiley Periodicals LLC.)

Introduction: This study investigated the comparability of cerebrospinal fluid (CSF) cutoffs for Elecsys immunoassays for amyloid beta (Aβ)42/Aβ40 or Aβ42/phosphorylated tau (p-tau)181 and the effects of measurement variability when predicting Alzheimer's disease (AD)-related outcomes (i.e., Aβ-positron emission tomography [PET] visual read and AD neuropathology)., Methods: We studied 750 participants (BioFINDER study, Alzheimer's Disease Neuroimaging Initiative [ADNI], and University of California San Francisco [UCSF]). Youden's index was used to identify cutoffs and to calculate accuracy (Aβ-PET visual read as outcome). Using longitudinal variability in Aβ-negative controls, we identified a gray zone around cut-points where the risk of an inconsistent predicted outcome was >5%., Results: For Aβ42/Aβ40, cutoffs across cohorts were <0.059 (BioFINDER), <0.057 (ADNI), and <0.058 (UCSF). For Aβ42/p-tau181, cutoffs were <41.90 (BioFINDER), <39.20 (ADNI), and <46.02 (UCSF). Accuracy was ≈90% for both Aβ42/Aβ40 and Aβ42/p-tau181 using these cutoffs. Using Aβ-PET as an outcome, 8.7% of participants fell within a gray zone interval for Aβ42/Aβ40, compared to 4.5% for Aβ42/p-tau181. Similar findings were observed using a measure of overall AD neuropathologic change (7.7% vs. 3.3%). In a subset with CSF and plasma Aβ42/40, the number of individuals within the gray zone was ≈1.5 to 3 times greater when using plasma Aβ42/40., Discussion: CSF Aβ42/p-tau181 was more robust to the effects of measurement variability, suggesting that it may be the preferred Elecsys-based measure in clinical practice and trials., (© 2023 The Authors. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)

The logopenic variant of primary progressive aphasia (lvPPA) is a neurodegenerative syndrome characterized linguistically by gradual loss of repetition and naming skills, resulting from left posterior temporal and inferior parietal atrophy. Here, we sought to identify which specific cortical loci are initially targeted by the disease (epicenters) and investigate whether atrophy spreads through pre-determined networks. First, we used cross-sectional structural MRI data from individuals with lvPPA to define putative disease epicenters using a surface-based approach paired with an anatomically-fine-grained parcellation of the cortical surface (i.e., HCP-MMP1.0 atlas). Second, we combined cross-sectional functional MRI data from healthy controls and longitudinal structural MRI data from individuals with lvPPA to derive the epicenter-seeded resting-state networks most relevant to lvPPA symptomatology and ascertain whether functional connectivity in these networks predicts longitudinal atrophy spread in lvPPA. Our results show that two partially distinct brain networks anchored to the left anterior angular and posterior superior temporal gyri epicenters were preferentially associated with sentence repetition and naming skills in lvPPA. Critically, the strength of connectivity within these two networks in the neurologically-intact brain significantly predicted longitudinal atrophy progression in lvPPA. Taken together, our findings indicate that atrophy progression in lvPPA, starting from inferior parietal and temporo-parietal junction regions, predominantly follows at least two partially non-overlapping pathways, which may influence the heterogeneity in clinical presentation and prognosis.

Importance: The neurological substrates of visual artistic creativity (VAC) are unknown. VAC is demonstrated here to occur early in frontotemporal dementia (FTD), and multimodal neuroimaging is used to generate a novel mechanistic hypothesis involving dorsomedial occipital cortex enhancement. These findings may illuminate a novel mechanism underlying human visual creativity., Objective: To determine the anatomical and physiological underpinnings of VAC in FTD., Design, Setting, and Participants: This case-control study analyzed records of 689 patients who met research criteria for an FTD spectrum disorder between 2002 and 2019. Individuals with FTD and emergence of visual artistic creativity (VAC-FTD) were matched to 2 control groups based on demographic and clinical parameters: (1) not visually artistic FTD (NVA-FTD) and (2) healthy controls (HC). Analysis took place between September 2019 to December 2021., Main Outcomes and Measures: Clinical, neuropsychological, genetic, and neuroimaging data were analyzed to characterize VAC-FTD and compare VAC-FTD with control groups., Results: Of 689 patients with FTD, 17 (2.5%) met VAC-FTD inclusion criteria (mean [SD] age, 65 [9.7] years; 10 [58.8%] female). NVA-FTD (n = 51; mean [SD] age, 64.8 [7] years; 25 [49.0%] female) and HC (n = 51; mean [SD] age, 64.5 [7.2] years; 25 [49%] female) groups were well matched to VAC-FTD demographically. Emergence of VAC occurred around the time of onset of symptoms and was disproportionately seen in patients with temporal lobe predominant degeneration (8 of 17 [47.1%]). Atrophy network mapping identified a dorsomedial occipital region whose activity inversely correlated, in healthy brains, with activity in regions found within the patient-specific atrophy patterns in VAC-FTD (17 of 17) and NVA-FTD (45 of 51 [88.2%]). Structural covariance analysis revealed that the volume of this dorsal occipital region was strongly correlated in VAC-FTD, but not in NVA-FTD or HC, with a volume in the primary motor cortex corresponding to the right-hand representation., Conclusions and Relevance: This study generated a novel hypothesis about the mechanisms underlying the emergence of VAC in FTD. These findings suggest that early lesion-induced activation of dorsal visual association areas may predispose some patients to the emergence of VAC under certain environmental or genetic conditions. This work sets the stage for further exploration of enhanced capacities arising early in the course of neurodegeneration.

Lecanemab (Leqembi®) is approved in the United States for the treatment of Alzheimer's disease (AD) to be initiated in early AD (mild cognitive impairment [MCI] due to AD or mild AD dementia) with confirmed brain amyloid pathology. Appropriate Use Recommendations (AURs) are intended to help guide the introduction of new therapies into real-world clinical practice. Community dwelling patients with AD differ from those participating in clinical trials. Administration of lecanemab at clinical trial sites by individuals experienced with monoclonal antibody therapy also differs from the community clinic-based administration of lecanemab. These AURs use clinical trial data as well as research and care information regarding AD to help clinicians administer lecanemab with optimal safety and opportunity for effectiveness. Safety and efficacy of lecanemab are known only for patients like those participating in the phase 2 and phase 3 lecanemab trials, and these AURs adhere closely to the inclusion and exclusion criteria of the trials. Adverse events may occur with lecanemab including amyloid related imaging abnormalities (ARIA) and infusion reactions. Monitoring guidelines for these events are detailed in this AUR. Most ARIA with lecanemab is asymptomatic, but a few cases are serious or, very rarely, fatal. Microhemorrhages and rare macrohemorrhages may occur in patients receiving lecanemab. Anticoagulation increases the risk of hemorrhage, and the AUR recommends that patients requiring anticoagulants not receive lecanemab until more data regarding this interaction are available. Patients who are apolipoprotein E ε4 (APOE4) gene carriers, especially APOE4 homozygotes, are at higher risk for ARIA, and the AUR recommends APOE genotyping to better inform risk discussions with patients who are lecanemab candidates. Clinician and institutional preparedness are mandatory for use of lecanemab, and protocols for management of serious events should be developed and implemented. Communication between clinicians and therapy candidates or those on therapy is a key element of good clinical practice for the use of lecanemab. Patients and their care partners must understand the potential benefits, the potential harms, and the monitoring requirements for treatment with this agent. Culture-specific communication and building of trust between clinicians and patients are the foundation for successful use of lecanemab., Competing Interests: JC has provided consultation to Acadia, Actinogen, Acumen, AlphaCognition, Aprinoia, AriBio, Artery, Biogen, BioVie, Cassava, Cerecin, Diadem, EIP Pharma, Eisai, GemVax, Genentech, GAP Innovations, Janssen, Jocasta, Karuna, Lilly, Lundbeck, LSP, Merck, NervGen, Novo Nordisk, Oligomerix, Optoceutics, Ono, Otsuka, PRODEO, Prothena, ReMYND, Roche, Sage Therapeutics, Signant Health, Simcere, Sunbird Bio, Suven, SynapseBio, TrueBinding, ,Vaxxinity, and Wren pharmaceutical, assessment, and investment companies. JC is supported by NIGMS grant P20GM109025; NINDS grant U01NS093334; NIA grant R01AG053798; NIA grant P20AG068053; NIA grant P30AG072959; NIA grant R35AG71476; Alzheimer’s Disease Drug Discovery Foundation (ADDF); Ted and Maria Quirk Endowment; and the Joy Chambers-Grundy Endowment. LGA has provided consultation to Eli Lilly, Biogen, Two Labs, FL Dept Health, Genentech, NIH Biobank, Eli Lilly, GE Healthcare, Eisai, Roche Diagnostics, and Alnylam. LGA receives the following research support: NIA U01 AG057195, NIA R01 AG057739, NIA P30 AG010133, Alzheimer Association LEADS GENETICS 19-639372, Alzheimer Association SG-23-1061716, Roche Diagnostics RD005665, AVID Pharmaceuticals, Life Molecular Imaging. LGA has received honoraria for participating in independent data safety monitoring boards and providing educational CME lectures and programs. LGA has stock in Cassava Sciences. GDR has provided consultation to Eli Lilly, Eisai, Roche, GE Healthcare, Johnson and Johnson and Genentech pharmaceutical companies. He receives grant support from NIH, Alzheimer’s Association, American College of Radiology, Rainwater Charitable Foundation, Genentech (via the Alliance for Therapies in Neuroscience) and from Avid Radiopharmaceuticals, GE Healthcare and Life Molecular Imaging (view the New IDEAS study). AA has received honoraria for consulting; participating in independent data safety monitoring boards; providing educational lectures, programs, and materials; or serving on advisory boards for AbbVie, Acadia, Allergan, the Alzheimer’s Association, Axovant, AZ Therapies, Biogen, Eisai, Grifols, Harvard Medical School Graduate Continuing Education, JOMDD, Lundbeck, Merck, Roche/Genentech, Novo Nordisk, Qynapse, Sunovion, Suven, and Synexus. AA receives book royalties from Oxford University Press. AA receives institutional research grant/contract funding from NIA/NIH 1P30AG072980, AZ DHS CTR040636, Washington University St Louis, and Gates Ventures. His institution receives/received funding for clinical trial grants, contracts and projects from government, consortia, foundations, and companies for which he serves/served as contracted site-PI. AA served as site-PI for the EMERGE study at his previous institution. PA has received research funding from NIA, FNIH, the Alzheimer’s Association, Janssen, Lilly and Eisai, and personal fees from Biogen, Merck, Roche, Abbvie, ImmunoBrain Checkpoint, Rainbow Medical and Shionogi. SS was a site PI and co-chair of the investigator steering committee for the ENGAGE trial and he receives research support and consultancy fees from Lilly, Biogen, Avid, Eisai, Genentech, and Roche. SMG is on the Data Safety Monitoring Board for DIAN-TU and has been a consultant for Eli Lilly. SH is owner of and a full-time employee of Pentara Corporation which consults for both Biogen and Eisai and many other AD clients. DS is a director and consultant of Prothena Biosciences and serves on an Advisory Board for Eisai. MW has served on Advisory Boards for Eli Lilly, Cerecin/Accera, Roche, Alzheon, Inc., Merck Sharp and Dohme Corp., Nestle/Nestec, PCORI/PPRN, Dolby Family Ventures, National Institute on Aging (NIA), Brain Health Registry and ADNI. He serves on Editorial Boards for Alzheimer’s and Dementia, TMRI and MRI. He has provided consulting and/or acted as a speaker to Cerecin/Accera, Inc., BioClinica, Nestle/Nestec, Roche, Genentech, NIH, The Buck Institute for Research on Aging, FUJIFILM-Toyama Chemical (Japan), Garfield Weston, Baird Equity Capital, University of Southern California (USC), Cytox, and Japanese Organization for Medical Device Development, Inc. (JOMDD), Peerview Internal Medicine, Vida Ventures, Medscape, Eisai, Korean Dementia Society, China Association for Alzheimer’s Disease (CAAD, and T3D Therapeutics. He holds stock options with Alzheon, Inc., Alzeca, and Anven. RCP has served as a consultant for Roche, Inc.; Genentech, Inc.; Eisai, Inc.; Eli Lilly, Inc.; and Nestle, Inc. he receives grant support from the National Institutes of Health. SS was a site PI for CLARITY and ENGAGE and co-chair of the investigator steering committee for the ENGAGE trial and his hospital receives research support from Lilly, Biogen, Avid, Eisai, Genentech, Roche and he receives consultancy fees from Lilly, Biogen, Avid, Eisai, Genentech, Roche, Novo Nordisk, Acumen and Prothena.

Objective. The differential diagnosis of behavioral variant frontotemporal dementia (bvFTD) and Alzheimer's disease (AD) remains challenging in underrepresented, underdiagnosed groups, including Latinos, as advanced biomarkers are rarely available. Recent guidelines for the study of dementia highlight the critical role of biomarkers. Thus, novel cost-effective complementary approaches are required in clinical settings. Approach . We developed a novel framework based on a gradient boosting machine learning classifier, tuned by Bayesian optimization, on a multi-feature multimodal approach (combining demographic, neuropsychological, magnetic resonance imaging (MRI), and electroencephalography/functional MRI connectivity data) to characterize neurodegeneration using site harmonization and sequential feature selection. We assessed 54 bvFTD and 76 AD patients and 152 healthy controls (HCs) from a Latin American consortium (ReDLat). Main results . The multimodal model yielded high area under the curve classification values (bvFTD patients vs HCs: 0.93 (±0.01); AD patients vs HCs: 0.95 (±0.01); bvFTD vs AD patients: 0.92 (±0.01)). The feature selection approach successfully filtered non-informative multimodal markers (from thousands to dozens). Results . Proved robust against multimodal heterogeneity, sociodemographic variability, and missing data. Significance . The model accurately identified dementia subtypes using measures readily available in underrepresented settings, with a similar performance than advanced biomarkers. This approach, if confirmed and replicated, may potentially complement clinical assessments in developing countries., (Creative Commons Attribution license.)

Background: The neurobiological origins of the early and predominant behavioral changes seen in the behavioral variant of Alzheimer's disease (bvAD) remain unclear. A selective loss of Von Economo neurons (VENs) and phylogenetically related neurons have been observed in behavioral variant frontotemporal dementia (bvFTD) and several psychiatric diseases. Here, we assessed whether these specific neuronal populations show a selective loss in bvAD., Methods: VENs and GABA receptor subunit theta (GABRQ)-immunoreactive pyramidal neurons of the anterior cingulate cortex (ACC) were quantified in post-mortem tissue of patients with bvAD (n = 9) and compared to typical AD (tAD, n = 6), bvFTD due to frontotemporal lobar degeneration based on TDP-43 pathology (FTLD, n = 18) and controls (n = 13) using ANCOVAs adjusted for age and Bonferroni corrected. In addition, ratios of VENs and GABRQ-immunoreactive (GABRQ-ir) pyramidal neurons over all Layer 5 neurons were compared between groups to correct for overall Layer 5 neuronal loss., Results: The number of VENs or GABRQ-ir neurons did not differ significantly between bvAD (VENs: 26.0 ± 15.3, GABRQ-ir pyramidal: 260.4 ± 87.1) and tAD (VENs: 32.0 ± 18.1, p = 1.00, GABRQ-ir pyramidal: 349.8 ± 109.6, p = 0.38) and controls (VENs: 33.5 ± 20.3, p = 1.00, GABRQ-ir pyramidal: 339.4 ± 95.9, p = 0.37). Compared to bvFTD, patients with bvAD showed significantly more GABRQ-ir pyramidal neurons (bvFTD: 140.5 ± 82.658, p = 0.01) and no significant differences in number of VENs (bvFTD: 10.9 ± 13.8, p = 0.13). Results were similar when assessing the number of VENs and GABRQ-ir relative to all neurons of Layer 5., Discussion: VENs and phylogenetically related neurons did not show a selective loss in the ACC in patients with bvAD. Our results suggest that, unlike in bvFTD, the clinical presentation in bvAD may not be related to the loss of VENs and related neurons in the ACC., (© 2022. The Author(s).)

Aducanumab (Aduhelm) is approved in the United States for the treatment of patients with mild cognitive impairment due to Alzheimer's disease or mild AD dementia. Aducanumab Appropriate Use Recommendations (AURs) have been published and have helped guide best practices for use of aducanumab. As real-world use has occurred and more information has accrued, the AURs require refinement. We update the AURs to better inform appropriate patient selection and improve shared decision-making, safety monitoring, and risk mitigation in treated patients. Based on evolving experience we emphasize the importance of detecting past medical conditions that may predispose to amyloid related imaging abnormalities (ARIA) or may increase the likelihood of ARIA complications including autoimmune or inflammatory conditions, seizures, or disorders associated with extensive white matter pathology. The apolipoprotein E ε4 (APOE4) genotype is strongly associated with ARIA and exhibits a gene dose effect. We recommend that clinicians perform APOE genotyping to better inform patient care decisions, discussions regarding risk, and clinician vigilance concerning ARIA. As most ARIA occurs during the titration period of aducanumab, we suggest performing MRI before the 5th, 7th, 9th, and 12th infusions to improve detection. Uncommonly, ARIA may be recurrent or serious; we suggest additional parameters for treatment discontinuation taking these observations into account. It is important to continue to learn from the real-world use of aducanumab and the AURs will continue to evolve as new information becomes available. This AUR update does not address efficacy, price, or insurance coverage and is provided to assist clinicians to establish best practices for use of aducanumab in the treatment of patients with mild cognitive impairment and mild Alzheimer's dementia., Competing Interests: JC has provided consultation to Acadia, Alkahest, AriBio, Avanir, Axsome, Behren Therapeutics, Biogen, Cassava, Cerecin, Cerevel, Cortexyme, EIP Pharma, Eisai, GemVax, Genentech, Green Valley, Grifols, Janssen, Jazz, Karuna, LSP, Merck, Novo Nordisk, Otsuka, ReMYND, Resverlogix, Roche, Signant Health, Sunovion, Suven, United Neuroscience, and Unlearn AI pharmaceutical and assessment companies. JC owns the copyright of the Neuropsychiatric Inventory. JC has the following research support: NIGMS P20GM109025; NINDS U01NS093334; NIA R01AG053798; NIA P20AG068053; NIA R35AG71476. GDR has provided consultation to Eli Lilly, Eisai, Roche, GE Healthcare, Johnson and Johnson and Genentech pharmaceutical companies. He receives grant support from Genentech (via the Alliance for Therapies in Neuroscience) and from Avid Radiopharmaceuticals, GE Healthcare and Life Molecular Imaging (view the New IDEAS study). MS provided consultation to Alzheon, Neurotrope, Biogen, Cortexyme, Danone, Regeneron, Roche-Genentech, Stage 2 Innovations, Acadia; he has stock or stock options (Brain Health Inc, NeuroReserve, NeuroTau, Optimal Cognitive Health Company, uMethod Health, Versanum, Athira. AA has received honoraria for consulting; participating in independent data safety monitoring boards; providing educational lectures, programs, and materials; or serving on advisory boards for AbbVie, Acadia, Allergan, the Alzheimer's Association, Axovant, AZ Therapies, Biogen, Eisai, Grifols, Harvard Medical School Graduate Continuing Education, JOMDD, Lundbeck, Merck, Roche/Genentech, Novo Nordisk, Qynapse, Sunovion, Suven, and Synexus. AA receives book royalties from Oxford University Press. AA receives institutional research grant/contract funding from NIA/NIH 1P30AG072980, AZ DHS CTR040636, Washington University St Louis, and Gates Ventures. His institution receives/received funding for clinical trial grants, contracts and projects from government, consortia, foundations, and companies for which he serves/served as contracted site-PI. AA served as site-PI for the EMERGE study at his previous institution. PA has received research funding from NIA, FNIH, the Alzheimer's Association, Janssen, Lilly and Eisai, and personal fees from Biogen, Merck, Roche, Abbvie, ImmunoBrain Checkpoint, Rainbow Medical and Shionogi. SS was a site PI and co-chair of the investigator steering committee for the ENGAGE trial and he receives research support and consultancy fees from Lilly, Biogen, Avid, Eisai, Genentech, and Roche. LGA has provided consultation to Eli Lilly, Biogen, and Two Labs. LGA receives the following research support: NIA U01 AG057195, NIA R01 AG057739, NIA P30 AG010133, Alzheimer Association LEADS GENETICS 19-639372, Roche Diagnostics RD005665, AVID Pharmaceuticals, Life Molecular Imaging. LGA has received honoraria for participating in independent data safety monitoring boards and providing educational CME lectures and programs. LGA has stock in Cassava Sciences. SH is a full-time employee of Pentara Corporation. MS has provided consultation to Alzheon, Biogen, Cortexyme, Roche-Genentech, Stage 2 Innovations/Renew Research, Acadia, T3D, Eisai, and KeifeRx. He is on the Speaker’s Bureau for Health and Wellness Partners. He holds stock/options in rain Health Inc, NeuroTau, Optimal Cognitive Health Company, uMethod Health, Versanum, Athira, and Cognoptix. DS is a director and consultant of Prothena Biosciences and serves on an Advisory Board for Eisai. MW has served on Advisory Boards for Eli Lilly, Cerecin/Accera, Roche, Alzheon, Inc., Merck Sharp and Dohme Corp., Nestle/Nestec, PCORI/PPRN, Dolby Family Ventures, National Institute on Aging (NIA), Brain Health Registry and ADNI. He serves on Editorial Boards for Alzheimer’s and Dementia, TMRI and MRI. He has provided consulting and/or acted as a speaker to Cerecin/Accera, Inc., BioClinica, Nestle/Nestec, Roche, Genentech, NIH, The Buck Institute for Research on Aging, FUJIFILM-Toyama Chemical (Japan), Garfield Weston, Baird Equity Capital, University of Southern California (USC), Cytox, and Japanese Organization for Medical Device Development, Inc. (JOMDD), Peerview Internal Medicine, Vida Ventures, Medscape, Eisai, Korean Dementia Society, China Association for Alzheimer’s Disease (CAAD, and T3D Therapeutics. He holds stock options with Alzheon, Inc., Alzeca, and Anven. SS was a site PI and co-chair of the investigator steering committee for the ENGAGE trial and he receives research support and consultancy fees from Lilly, Biogen, Avid, Eisai, Genentech, and Roche.

Objective: We aimed to test the hypothesis that elevated neocortical β-amyloid (Aβ), a hallmark feature of Alzheimer's disease (AD), predicts sex-specific cognitive trajectories in clinically normal older adults, with women showing greater risk of decline than men. Method: Florbetapir Aβ positron emission tomography (PET) was acquired in 149 clinically normal older adults (52% female, M age = 74). Participants underwent cognitive testing at baseline and during annual follow-up visits over a timespan of up to 5.14 years. Mixed-effects regression models evaluated whether relations between baseline neocortical Standardized Uptake Value Ratio (SUVR) and composite scores of episodic memory, executive functioning, and processing speed were moderated by sex (male/female) and apolipoprotein E (APOE) status (ε4 carrier/noncarrier). Results: Higher baseline SUVR was associated with longitudinal decline in episodic memory in women ( b = -1.32, p < .001) but not men ( b = -0.30, p = .28). Female APOE ε4 carriers with elevated SUVR showed particularly precipitous declines in episodic memory ( b = -4.33, p < .001) whereas other cognitive domains were spared. SUVR did not predict changes in executive functioning or processing speed, regardless of sex (ps >.63), though there was a main effect of SUVR on processing speed ( b = 2.50, p = .003). Conclusions: Clinically normal women with elevated Aβ are more vulnerable to episodic memory decline than men. Understanding sex-related differences in AD, particularly in preclinical stages, is crucial for guiding precision medicine approaches to early detection and intervention. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Introduction: Assessment of functional status is associated with risk of cognitive decline and diagnosis of dementia, and can be assessed by participants and study partners (SPs)., Methods: In 770 older adults enrolled in the Imaging Dementia-Evidence for Amyloid Scanning (IDEAS) study and the online Brain Health Registry (BHR), we estimated associations between online assessments and clinical variables related to Alzheimer's disease (AD) risk., Results: Worse online learning scores and SP-reported functional decline were associated with higher probability of AD dementia diagnosis and poor in-clinic cognitive assessment, and with higher odds of amyloid beta (Aβ) positivity when combined with participants' report of less decline. SP report of functional decline conferred predictive value independent of online cognitive assessments. Participants underreported decline compared to SPs., Discussion: The results support the validity of online assessments and their greater utilization in healthcare and research settings. Online SP-reported functional decline is an indicator of dementia and AD risk., (© 2020 the Alzheimer's Association.)

The links between β-amyloid (Aβ) and tau in Alzheimer's disease are unclear. Cognitively unimpaired persons with signs of Aβ pathology had increased cerebrospinal fluid (CSF) phosphorylated tau (P-tau181 and P-tau217) and total-tau (T-tau), which increased over time, despite no detection of insoluble tau aggregates [normal Tau positron emission tomography (PET)]. CSF P-tau and T-tau started to increase before the threshold for Amyloid PET positivity, while Tau PET started to increase after Amyloid PET positivity. Effects of Amyloid PET on Tau PET were mediated by CSF P-tau, and high CSF P-tau predicted increased Tau PET rates. Individuals with MAPT mutations and signs of tau deposition (but without Aβ pathology) had normal CSF P-tau levels. In 5xFAD mice, CSF tau increased when Aβ aggregation started. These results show that Aβ pathology may induce changes in soluble tau release and phosphorylation, which is followed by tau aggregation several years later in humans., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)

Mild cognitive impairment (MCI) is significantly misdiagnosed in the primary care setting due to multi-dimensional frictions and barriers associated with evaluating individuals' cognitive performance. To move toward large-scale cognitive screening, a global panel of clinicians and cognitive neuroscientists convened to elaborate on current challenges that hamper widespread cognitive performance assessment. This report summarizes a conceptual framework and provides guidance to clinical researchers and test developers and suppliers to inform ongoing refinement of cognitive evaluation. This perspective builds upon a previous article in this series, which outlined the rationale for and potentially against efforts to promote widespread detection of MCI. This working group acknowledges that cognitive screening by default is not recommended and proposes large-scale evaluation of individuals with a concern or interest in their cognitive performance. Such a strategy can increase the likelihood to timely and effective identification and management of MCI. The rising global incidence of AD demands innovation that will help alleviate the burden to healthcare systems when coupled with the potentially near-term approval of disease-modifying therapies. Additionally, we argue that adequate infrastructure, equipment, and resources urgently should be integrated in the primary care setting to optimize the patient journey and accommodate widespread cognitive evaluation., Competing Interests: MB is affiliated with the Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain; and with the Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Spain. Private research funding sources include Grifols SA; Caixabank S.A.; Life Molecular Imaging; Araclon Biotech; Laboratorios Echevarne; Festival Castell Paralada; Bonpreu/Esclat; and Famila Carbó. Public grants include those from Instituto de Salud Carlos III. Ministerio de Salud. Gobierno de España; Dirección General de Farmacia. Ministerio de Salud. Gobierno de España; and European Commission:H2020 program, Innovative Medicine Initiative (IMI-2); and ERA-NET NEURON program, European Marie Sklodowska Curie. Advisory work includes that for Araclon Biotech, Biogen, Bioibérica, Eisai, Grifols, Lilly, Merck, Nutricia, Roche, Oryzon, Schwabe Farma, Servier, and Kyowa Kirin. BD is affiliated with the Institute of Memory and Alzheimer’s Disease (IM2A), Department of Neurology, Salpêtrière Hospital, AP-HP, Sorbonne-Université, Paris, France. JI is affiliated as an Assistant Professor-Adjunct (Group1) with the Department of Family Practice at Queen’s University. She was also a panelist for Hoffman-La Roche Limited, Ottawa, on an Alzheimer’s Disease Panel. She is involved with the Canadian Consortium on Neurodegeneration in Aging (CCNA), Extension Study as a Co- Investigator and Research Coordinator. AI received lecture fees from Eisai, Janssen, Otsuka, Eli Lilly, MSD, Chugai-Roche, Daiichi-Sankyo, Alnylam, Takeda, UCB, Ono, Integra Japan, IQVIA, Fuji Rebio, Biogen, and advisory fees from Janssen during the past three years. AP reports personal fees from Acadia Pharmaceuticals, Functional Neuromodulation, Neurim Pharmaceuticals, Grifols, Eisai, BioXcel, Tetra Discovery Partners, and Merck; grants from AstraZeneca, Avanir, Biogen, Biohaven, Eisai, Eli Lilly, Janssen, Genentech/Roche, Novartis, Merck, as well as funding from NIA, NIMH, DOD. KLP receives grant funding from the National Institute on Aging, the National Institute of Neurological Disorders and Stroke, the Global Brain Health Institute, and Quest Diagnostics. BV has consultancy and research grants from Roche, Biogen, EISAI, Nestle, Lilly, Cerecin, and Merck. HH is an employee of Eisai Inc. and serves as Senior Associate Editor for the Journal Alzheimer’s and Dementia; during the past three years he had received lecture fees from Servier, Biogen and Roche, research grants from Pfizer, Avid, and MSD Avenir (paid to the institution), travel funding from Eisai, Functional Neuromodulation, Axovant, Eli Lilly and company, Takeda and Zinfandel, GE-Healthcare and Oryzon Genomics, consultancy fees from Qynapse, Jung Diagnostics, Cytox Ltd., Axovant, Anavex, Takeda and Zinfandel, GE Healthcare, Oryzon Genomics, and Functional Neuromodulation, and participated in scientific advisory boards of Functional Neuromodulation, Axovant, Eisai, Eli Lilly and company, Cytox Ltd., GE Healthcare, Takeda and Zinfandel, Oryzon Genomics and Roche Diagnostics. He is co-inventor in the following patents as a scientific expert and has received no royalties: In Vitro Multiparameter Determination Method for The Diagnosis and Early Diagnosis of Neurodegenerative Disorders Patent Number: 8916388; In Vitro Procedure for Diagnosis and Early Diagnosis of Neurodegenerative Diseases Patent Number: 8298784; Neurodegenerative Markers for Psychiatric Conditions Publication Number: 20120196300; In Vitro Multiparameter Determination Method for The Diagnosis and Early Diagnosis of Neurodegenerative Disorders Publication Number: 20100062463; In Vitro Method for The Diagnosis and Early Diagnosis of Neurodegenerative Disorders Publication Number: 20100035286; In Vitro Procedure for Diagnosis and Early Diagnosis of Neurodegenerative Diseases Publication Number: 20090263822; In Vitro Method for The Diagnosis of Neurodegenerative Diseases Patent Number: 7547553; CSF Diagnostic in Vitro Method for Diagnosis of Dementias and Neuroinflammatory Diseases Publication Number: 20080206797; In Vitro Method for The Diagnosis of Neurodegenerative Diseases Publication Number: 20080199966; Neurodegenerative Markers for Psychiatric Conditions Publication Number: 20080131921. AV is an employee of Eisai Inc. and received lecture honoraria from Roche, MagQu LLC, and Servier.

Emerging digital tools have the potential to enable a new generation of qualitative and quantitative assessment of cognitive performance. Moreover, the ubiquity of consumer electronics, such as smartphones and tablets, can be harnessed to support large-scale self-assessed cognitive screening with benefit to healthcare systems and consumers. A wide variety of apps, wearables, and new digital technologies are either available or in development for the detection of mild cognitive impairment (MCI), a risk factor for dementia. Two categories of novel methodologies may be considered: passive technologies (which monitor a user's behavior without active user input) and interactive assessments (which require active user input). Such examinations can be self-administered, supervised by a caregiver, or conducted by an informant at home or outside of a clinical setting. These direct-to-consumer tools have the potential to sidestep barriers associated with cognitive evaluation in primary care, thus improving access to cognitive assessments. Although direct-to-consumer cognitive assessment is associated with its own barriers, including test validation, user experience, and technological concerns, it is conceivable that these issues can be addressed so that a large-scale, self-assessed cognitive evaluation that would represent an initial cognitive screen may be feasible in the future., Competing Interests: MNS Royalty: HarperCollins, Stock: uMethod Health, Brain Health, Inc, Optimal Cognitive Health Company, M3 Biosciences, Versanum, NeuroReserveAlzheon and Athira, Speakers Bureau: Peerview and Medscape and HWP, Consultant: Biogen, Bracket/Signant, Neurotrope, Cortexyme, Roche, Grifols, Sanofi, Regeneron, Eisai, Neuronix, Acadia. MB is affiliated with the Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain; and with the Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Spain. Private research funding sources include Grifols SA; Caixabank S.A.; Life Molecular Imaging; Araclon Biotech; Laboratorios Echevarne; Festival Castell Paralada; Bonpreu/Esclat; and Famila Carbó. Public grants include those from Instituto de Salud Carlos III. Ministerio de Salud. Gobierno de España; Dirección General de Farmacia. Ministerio de Salud. Gobierno de España; and European Commission:H2020 program, Innovative Medicine Initiative (IMI-2); and ERA-NET NEURON program, European Marie Sklodowska Curie. Advisory work includes that for Araclon Biotech, Biogen, Bioibérica, Eisai, Grifols, Lilly, Merck, Nutricia, Roche, Oryzon, Schwabe Farma, Servier, and Kyowa Kirin. PMD has received research grants (through Duke University) from Avid, Lilly, Neuronetrix, Avanir, Bauch, Alzheimer’s Drug Discovery Foundation, Cure Alzheimer’s Fund, Wrenn Trust, DOD, ONR, and NIH. PMD has received speaking or advisory fees from Anthrotronix, Neuroptix, Genomind, Clearview, Cognicity, Nutricia, Living Media, Verily, RBC, Brain Canada, and CEOs Against Alzheimers. PMD owns shares in Muses Labs, Anthrotronix, Evidation Health, Turtle Shell Technologies and Advera Health Analytics whose products are not discussed here. He has received travel support from World Economic Forum, CCABH and Canaan Ventures. PMD served/serves on the board of Baycrest, AHEL, TLLF and TGHF. PMD is a co-inventor (through Duke) on patents relating to dementia biomarkers and therapies. BD is affiliated with the Institute of Memory and Alzheimer’s Disease (IM2A), Department of Neurology, Salpêtrière Hospital, AP-HP, Sorbonne-Université, Paris, France. JI is affiliated as an Assistant Professor-Adjunct (Group1) with the Department of Family Practice at Queen’s University. She was also a panelist for Hoffman-La Roche Limited, Ottawa, on an Alzheimer’s Disease Panel. She is involved with the Canadian Consortium on Neurodegeneration in Aging (CCNA), Extension Study as a Co- Investigator and Research Coordinator. AI received lecture fees from Eisai, Janssen, Otsuka, Eli Lilly, MSD, Chugai-Roche, Daiichi-Sankyo, Alnylam, Takeda, UCB, Ono, Integra Japan, IQVIA, Fuji Rebio, Biogen, and advisory fees from Janssen during the past three years. AP reports personal fees from Acadia Pharmaceuticals, Functional Neuromodulation, Neurim Pharmaceuticals, Grifols, Eisai, BioXcel, Tetra Discovery Partners, and Merck; grants from AstraZeneca, Avanir, Biogen, Biohaven, Eisai, Eli Lilly, Janssen, Genentech/Roche, Novartis, Merck, as well as funding from NIA, NIMH, DOD. KLP receives grant funding from the National Institute on Aging, the National Institute of Neurological Disorders and Stroke, the Global Brain Health Institute, and Quest Diagnostics. BV has consultancy and research grants from Roche, Biogen, EISAI, Nestle, Lilly, Cerecin, and Merck. HH is an employee of Eisai Inc. and serves as Senior Associate Editor for the Journal Alzheimer’s and Dementia; during the past three years he had received lecture fees from Servier, Biogen and Roche, research grants from Pfizer, Avid, and MSD Avenir (paid to the institution), travel funding from Eisai, Functional Neuromodulation, Axovant, Eli Lilly and company, Takeda and Zinfandel, GE-Healthcare and Oryzon Genomics, consultancy fees from Qynapse, Jung Diagnostics, Cytox Ltd., Axovant, Anavex, Takeda and Zinfandel, GE Healthcare, Oryzon Genomics, and Functional Neuromodulation, and participated in scientific advisory boards of Functional Neuromodulation, Axovant, Eisai, Eli Lilly and company, Cytox Ltd., GE Healthcare, Takeda and Zinfandel, Oryzon Genomics and Roche Diagnostics. He is co-inventor in the following patents as a scientific expert and has received no royalties: In Vitro Multiparameter Determination Method for the Diagnosis and Early Diagnosis of Neurodegenerative Disorders Patent Number: 8916388; In Vitro Procedure for Diagnosis and Early Diagnosis of Neurodegenerative Diseases Patent Number: 8298784; • Neurodegenerative Markers for Psychiatric Conditions Publication Number: 20120196300; In Vitro Multiparameter Determination Method for The Diagnosis and Early Diagnosis of Neurodegenerative Disorders Publication Number: 20100062463; In Vitro Method for The Diagnosis and Early Diagnosis of Neurodegenerative Disorders Publication Number: 20100035286; In Vitro Procedure for Diagnosis and Early Diagnosis of Neurodegenerative Diseases Publication Number: 20090263822; In Vitro Method for the Diagnosis of Neurodegenerative Diseases Patent Number: 7547553; CSF Diagnostic in Vitro Method for Diagnosis of Dementias and Neuroinflammatory Diseases Publication Number: 20080206797; In Vitro Method for The Diagnosis of Neurodegenerative Diseases Publication Number: 20080199966; Neurodegenerative Markers for Psychiatric Conditions Publication Number: 20080131921. AV is an employee of Eisai Inc. and received lecture honoraria from Roche, MagQu LLC, and Servier.

Disease-modifying pharmacotherapies for Alzheimer's Disease (AD) are currently in late-stage clinical development; once approved, new healthcare infrastructures and services, including primary healthcare, will be necessary to accommodate a huge demand for early and large-scale detection of AD. The increasing global accessibility of digital consumer electronics has opened up new prospects for early diagnosis and management of mild cognitive impairment (MCI) with particular regard to AD. This new wave of innovation has spurred research in both academia and industry, aimed at developing and validating a new "digital generation" of tools for the assessment of the cognitive performance. In light of this paradigm shift, an international working group (the Global Advisory Group on Future MCI Care Pathways) convened to elaborate on how digital tools may be optimally integrated in screening-diagnostic pathways of AD The working group developed consensus perspectives on new algorithms for large-scale screening, detection, and diagnosis of individuals with MCI within primary medical care delivery. In addition, the expert panel addressed operational aspects concerning the implementation of unsupervised at-home testing of cognitive performance. The ultimate intent of the working group's consensus perspectives is to provide guidance to developers of cognitive tests and tools to facilitate the transition toward globally accessible cognitive screening aimed at the early detection, diagnosis, and management of MCI due to AD., Competing Interests: MB is affiliated with the Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Universitat Internacional de Catalunya, Barcelona, Spain; and with the Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Spain. Private research funding sources include Grifols SA; Caixabank S.A.; Life Molecular Imaging; Araclon Biotech; Laboratorios Echevarne; Festival Castell Paralada; Bonpreu/Esclat; and Famila Carbó. Public grants include those from Instituto de Salud Carlos III. Ministerio de Salud. Gobierno de España; Dirección General de Farmacia. Ministerio de Salud. Gobierno de España; and European Commission:H2020 program, Innovative Medicine Initiative (IMI-2); and ERA-NET NEURON program, European Marie Sklodowska Curie. Advisory work includes that for Araclon Biotech, Biogen, Bioibérica, Eisai, Grifols, Lilly, Merck, Nutricia, Roche, Oryzon, Schwabe Farma, Servier, and Kyowa Kirin. PMD has received research grants (through Duke University) from Avid, Lilly, Neuronetrix, Avanir, Bauch, Alzheimer’s Drug Discovery Foundation, Cure Alzheimer’s Fund, Wrenn Trust, DOD, ONR, and NIH. PMD has received speaking or advisory fees from Anthrotronix, Neuroptix, Genomind, Clearview, Cognicity, Nutricia, Living Media, Verily, RBC, Brain Canada, and CEOs Against Alzheimers. PMD owns shares in Muses Labs, Anthrotronix, Evidation Health, Turtle Shell Technologies and Advera Health Analytics whose products are not discussed here. He has received travel support from World Economic Forum, CCABH and Canaan Ventures. PMD served/serves on the board of Baycrest, AHEL, TLLF and TGHF. PMD is a co-inventor (through Duke) on patents relating to dementia biomarkers and therapies. BD is affiliated with the Institute of Memory and Alzheimer’s Disease (IM2A), Department of Neurology, Salpêtrière Hospital, AP-HP, Sorbonne-Université, Paris, France. JI is affiliated as an Assistant Professor-Adjunct (Group1) with the Department of Family Practice at Queen’s University. She was also a panelist for Hoffman-La Roche Limited, Ottawa, on an Alzheimer’s Disease Panel. She is involved with the Canadian Consortium on Neurodegeneration in Aging (CCNA), Extension Study as a Co- Investigator and Research Coordinator. AI received lecture fees from Eisai, Janssen, Otsuka, Eli Lilly, MSD, Chugai-Roche, Daiichi-Sankyo, Alnylam, Takeda, UCB, Ono, Integra Japan, IQVIA, Fuji Rebio, Biogen, and advisory fees from Janssen during the past three years. AP reports personal fees from Acadia Pharmaceuticals, Functional Neuromodulation, Neurim Pharmaceuticals, Grifols, Eisai, BioXcel, Tetra Discovery Partners, and Merck; grants from AstraZeneca, Avanir, Biogen, Biohaven, Eisai, Eli Lilly, Janssen, Genentech/Roche, Novartis, Merck, as well as funding from NIA, NIMH, DOD. KLP receives grant funding from the National Institute on Aging, the National Institute of Neurological Disorders and Stroke, the Global Brain Health Institute, and Quest Diagnostics. BV has consultancy and research grants from Roche, Biogen, EISAI, Nestle, Lilly, Cerecin, and Merck. HH is an employee of Eisai Inc. and serves as Senior Associate Editor for the Journal Alzheimer’s and Dementia; during the past three years he had received lecture fees from Servier, Biogen and Roche, research grants from Pfizer, Avid, and MSD Avenir (paid to the institution), travel funding from Eisai, Functional Neuromodulation, Axovant, Eli Lilly and company, Takeda and Zinfandel, GE-Healthcare and Oryzon Genomics, consultancy fees from Qynapse, Jung Diagnostics, Cytox Ltd., Axovant, Anavex, Takeda and Zinfandel, GE Healthcare, Oryzon Genomics, and Functional Neuromodulation, and participated in scientific advisory boards of Functional Neuromodulation, Axovant, Eisai, Eli Lilly and company, Cytox Ltd., GE Healthcare, Takeda and Zinfandel, Oryzon Genomics and Roche Diagnostics. He is co-inventor in the following patents as a scientific expert and has received no royalties: In Vitro Multiparameter Determination Method for the Diagnosis and Early Diagnosis of Neurodegenerative Disorders Patent Number: 8916388; In Vitro Procedure for Diagnosis and Early Diagnosis of Neurodegenerative Diseases Patent Number: 8298784; Neurodegenerative Markers for Psychiatric Conditions Publication Number: 20120196300; In Vitro Multiparameter Determination Method for The Diagnosis and Early Diagnosis of Neurodegenerative Disorders Publication Number: 20100062463; In Vitro Method for The Diagnosis and Early Diagnosis of Neurodegenerative Disorders Publication Number: 20100035286; In Vitro Procedure for Diagnosis and Early Diagnosis of Neurodegenerative Diseases Publication Number: 20090263822; In Vitro Method for The Diagnosis of Neurodegenerative Diseases Patent Number: 7547553; CSF Diagnostic in Vitro Method for Diagnosis of Dementias and Neuroinflammatory Diseases Publication Number: 20080206797; In Vitro Method for The Diagnosis of Neurodegenerative Diseases Publication Number: 20080199966; Neurodegenerative Markers for Psychiatric Conditions Publication Number: 20080131921. AV is an employee of Eisai Inc. and received lecture honoraria from Roche, MagQu LLC, and Servier.

A 66-year-old woman presented with agrammatism and apraxia of speech, meeting criteria for non-fluent/agrammatic variant primary progressive aphasia (nfvPPA). However, three years later, she developed frontal/executive, short-term phonological memory, visuospatial, and visual memory deficits suggesting involvement of multiple brain networks. Multimodal neuroimaging showed damage of both fronto-striatal and posterior brain regions. She was found to have multiple pathological processes: corticobasal degeneration (CBD), Alzheimer's disease (AD), and TAR DNA-binding protein (TDP)-43 type A. We hypothesize that cognitive and neuroimaging findings consistent with damage to multiple brain networks, each associated with vulnerability to certain molecular disease subtypes, could indicate mixed pathology.

Non-fluent/agrammatic primary progressive aphasia (nfvPPA) is caused by neurodegeneration within the left fronto-insular speech and language production network (SPN). Graph theory is a branch of mathematics that studies network architecture (topology) by quantifying features based on its elements (nodes and connections). This approach has been recently applied to neuroimaging data to explore the complex architecture of the brain connectome, though few studies have exploited this technique in PPA. Here, we used graph theory on functional MRI resting state data from a group of 20 nfvPPA patients and 20 matched controls to investigate topological changes in response to focal neurodegeneration. We hypothesized that changes in the network architecture would be specific to the affected SPN in nfvPPA, while preserved in the spared default mode network (DMN). Topological configuration was quantified by hub location and global network metrics. Our findings showed a less efficiently wired and less optimally clustered SPN, while no changes were detected in the DMN. The SPN in the nfvPPA group showed a loss of hubs in the left fronto-parietal-temporal area and new critical nodes in the anterior left inferior-frontal and right frontal regions. Behaviorally, speech production score and rule violation errors correlated with the strength of functional connectivity of the left (lost) and right (new) regions respectively. This study shows that focal neurodegeneration within the SPN in nfvPPA is associated with network-specific topological alterations, with the loss and gain of crucial hubs and decreased global efficiency that were better accounted for through functional rather than structural changes. These findings support the hypothesis of selective network vulnerability in nfvPPA and may offer biomarkers for future behavioral intervention., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Chronic traumatic encephalopathy (CTE) is associated with pathological changes, yet detecting these changes during life has proven elusive. Positron emission tomography (PET) offers the potential for identifying such pathology. Few studies have been completed to date and their approaches and results have been diverse. It was the objective of this review to systematically examine relevant research using ligands for PET that bind to identified pathology in CTE. We focused on identification of patterns of binding and addressing gaps in knowledge of PET imaging for CTE. A comprehensive literature search was conducted. Data used were published on or before May 22, 2017. As the extant literature is limited, any peer-reviewed article assessing military, contact sports athletes, or professional fighters was considered for inclusion. The main outcomes were regional binding to brain regions identified through control comparisons or through clinical metrics (e.g., standardized uptake volume ratios). A total of 1207 papers were identified for review, of which six met inclusion criteria. Meta-analyses were planned but were deemed inappropriate given the small number of studies identified. Methodological concerns in these initial papers included small sample sizes, lack of a control comparison, use of nonstandard statistical procedures to quantify data, and interpretation of potentially off-target binding areas. Across studies, the hippocampi, amygdalae, and midbrain had reasonably consistent increased uptake. Evidence for increased uptake in cortical regions was less consistent. The evidence suggests that the field of PET imaging in those at risk for CTE remains nascent. As the field evolves to include more stringent studies, ligands for PET may prove an important tool in identifying CTE in vivo.

PSP is a pathologically defined neurodegenerative tauopathy with a variety of clinical presentations including typical Richardson's syndrome and other variant PSP syndromes. A large body of neuroimaging research has been conducted over the past two decades, with many studies proposing different structural MRI and molecular PET/SPECT biomarkers for PSP. These include measures of brainstem, cortical and striatal atrophy, diffusion weighted and diffusion tensor imaging abnormalities, [18F] fluorodeoxyglucose PET hypometabolism, reductions in striatal dopamine imaging and, most recently, PET imaging with ligands that bind to tau. Our aim was to critically evaluate the degree to which structural and molecular neuroimaging metrics fulfill criteria for diagnostic biomarkers of PSP. We queried the PubMed, Cochrane, Medline, and PSYCInfo databases for original research articles published in English over the past 20 years using postmortem diagnosis or the NINDS-SPSP criteria as the diagnostic standard from 1996 to 2016. We define a five-level theoretical construct for the utility of neuroimaging biomarkers in PSP, with level 1 representing group-level findings, level 2 representing biomarkers with demonstrable individual-level diagnostic utility, level 3 representing biomarkers for early disease, level 4 representing surrogate biomarkers of PSP pathology, and level 5 representing definitive PSP biomarkers of PSP pathology. We discuss the degree to which each of the currently available biomarkers fit into this theoretical construct, consider the role of biomarkers in the diagnosis of Richardson's syndrome, variant PSP syndromes and autopsy confirmed PSP, and emphasize current shortfalls in the field. © 2017 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society., (© 2017 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.)

Background: PSP is a neuropathologically defined disease entity. Clinical diagnostic criteria, published in 1996 by the National Institute of Neurological Disorders and Stroke/Society for PSP, have excellent specificity, but their sensitivity is limited for variant PSP syndromes with presentations other than Richardson's syndrome., Objective: We aimed to provide an evidence- and consensus-based revision of the clinical diagnostic criteria for PSP., Methods: We searched the PubMed, Cochrane, Medline, and PSYCInfo databases for articles published in English since 1996, using postmortem diagnosis or highly specific clinical criteria as the diagnostic standard. Second, we generated retrospective standardized clinical data from patients with autopsy-confirmed PSP and control diseases. On this basis, diagnostic criteria were drafted, optimized in two modified Delphi evaluations, submitted to structured discussions with consensus procedures during a 2-day meeting, and refined in three further Delphi rounds., Results: Defined clinical, imaging, laboratory, and genetic findings serve as mandatory basic features, mandatory exclusion criteria, or context-dependent exclusion criteria. We identified four functional domains (ocular motor dysfunction, postural instability, akinesia, and cognitive dysfunction) as clinical predictors of PSP. Within each of these domains, we propose three clinical features that contribute different levels of diagnostic certainty. Specific combinations of these features define the diagnostic criteria, stratified by three degrees of diagnostic certainty (probable PSP, possible PSP, and suggestive of PSP). Clinical clues and imaging findings represent supportive features., Conclusions: Here, we present new criteria aimed to optimize early, sensitive, and specific clinical diagnosis of PSP on the basis of currently available evidence. © 2017 International Parkinson and Movement Disorder Society., (© 2017 International Parkinson and Movement Disorder Society.)

Background: Mild cognitive impairment (MCI) has an uncertain etiology and prognosis and may be challenging for clinicians to discuss with patients and families. Amyloid imaging may aid specialists in determining MCI etiology and prognosis, but creates novel challenges related to disease labeling., Methods: We convened a workgroup to formulate recommendations for clinicians providing care to MCI patients., Results: Clinicians should use the MCI diagnosis to validate patient and family concerns and educate them that the patient's cognitive impairment is not normal for his or her age and education level. The MCI diagnosis should not be used to avoid delivering a diagnosis of dementia. For patients who meet Appropriate Use Criteria after standard-of-care clinical workup, amyloid imaging may position specialists to offer more information about etiology and prognosis. Clinicians must set appropriate expectations, including ensuring that patients and families understand the limitations of amyloid imaging. Communication of negative results should include that patients remain at elevated risk for dementia and that negative scans do not indicate a specific diagnosis or signify brain health. Positive amyloid imaging results should elicit further monitoring and conversations about appropriate advance planning. Clinicians should offer written summaries, including referral to appropriate social services., Conclusions: In patients with MCI, there is a need to devote considerable time and attention to patient education and shared decision-making. Amyloid imaging may be a tool to aid clinicians. Careful management of patient expectations and communication of scan results will be critical to the appropriate use of amyloid imaging information.

Objective: To characterize in vivo signatures of pathological diagnosis in a large cohort of patients with primary progressive aphasia (PPA) variants defined by current diagnostic classification., Methods: Extensive clinical, cognitive, neuroimaging, and neuropathological data were collected from 69 patients with sporadic PPA, divided into 29 semantic (svPPA), 25 nonfluent (nfvPPA), 11 logopenic (lvPPA), and 4 mixed PPA. Patterns of gray matter (GM) and white matter (WM) atrophy at presentation were assessed and tested as predictors of pathological diagnosis using support vector machine (SVM) algorithms., Results: A clinical diagnosis of PPA was associated with frontotemporal lobar degeneration (FTLD) with transactive response DNA-binding protein (TDP) inclusions in 40.5%, FTLD-tau in 40.5%, and Alzheimer disease (AD) pathology in 19% of cases. Each variant was associated with 1 typical pathology; 24 of 29 (83%) svPPA showed FTLD-TDP type C, 22 of 25 (88%) nfvPPA showed FTLD-tau, and all 11 lvPPA had AD. Within FTLD-tau, 4R-tau pathology was commonly associated with nfvPPA, whereas Pick disease was observed in a minority of subjects across all variants except for lvPPA. Compared with pathologically typical cases, svPPA-tau showed significant extrapyramidal signs, greater executive impairment, and severe striatal and frontal GM and WM atrophy. nfvPPA-TDP patients lacked general motor symptoms or significant WM atrophy. Combining GM and WM volumes, SVM analysis showed 92.7% accuracy to distinguish FTLD-tau and FTLD-TDP pathologies across variants., Interpretation: Each PPA clinical variant is associated with a typical and most frequent cognitive, neuroimaging, and neuropathological profile. Specific clinical and early anatomical features may suggest rare and atypical pathological diagnosis in vivo. Ann Neurol 2017;81:430-443., (© 2017 American Neurological Association.)

The goal of this paper was to evaluate the in vivo kinetics of the novel tau-specific PET radioligand 18 F-AV-1451 in cognitively healthy control (HC) and Alzheimer disease (AD) subjects, using reference region analyses., Methods: 18 F-AV-1451 PET imaging was performed on 43 subjects (5 young HCs, 23 older HCs, and 15 AD subjects). Data were collected from 0 to 150 min after injection, with a break from 100 to 120 min. T1-weighted MR images were segmented using FreeSurfer to create 14 bilateral regions of interest (ROIs). In all analyses, cerebellar gray matter was used as the reference region. Nondisplaceable binding potentials (BP ND s) were calculated using the simplified reference tissue model (SRTM) and SRTM2; the Logan graphical analysis distribution volume ratio (DVR) was calculated for 30-150 min (DVR30-150). These measurements were compared with each other and used as reference standards for defining an appropriate 20-min window for the SUV ratio (SUVR). Pearson correlations were used to compare the reference standards to 20-min SUVRs (start times varied from 30 to 130 min), for all values, for ROIs with low 18 F-AV-1451 binding (lROIs, mean of BP ND + 1 and DVR30-150 < 1.5), and for ROIs with high 18 F-AV-1451 binding (hROIs, mean of BP ND + 1 and DVR30-150 > 1.5)., Results: SRTM2 BP ND + 1 and DVR30-150 were in good agreement. Both were in agreement with SRTM BP ND + 1 for lROIs but were greater than SRTM BP ND + 1 for hROIs, resulting in a nonlinear relationship. hROI SUVRs increased from 80-100 to 120-140 min by 0.24 ± 0.15. The SUVR time interval resulting in the highest correlation and slope closest to 1 relative to the reference standards for all values was 120-140 min for hROIs, 60-80 min for lROIs, and 80-100 min for lROIs and hROIs. There was minimal difference between methods when statistical significance between ADs and HCs was calculated., Conclusion: Despite later time periods providing better agreement between reference standards and SUVRs for hROIs, a good compromise for studying lROIs and hROIs is SUVR80-100. The lack of SUVR plateau for hROIs highlights the importance of precise acquisition time for longitudinal assessment., (© 2017 by the Society of Nuclear Medicine and Molecular Imaging.)

SEE HANSSON AND GOURAS DOI101093/AWW146 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: Although some brain regions such as precuneus and lateral temporo-parietal cortex have been shown to be more vulnerable to Alzheimer's disease than other areas, a mechanism underlying the differential regional vulnerability to Alzheimer's disease remains to be elucidated. Using fluorodeoxyglucose and Pittsburgh compound B positron emission tomography imaging glucose metabolism and amyloid-β deposition, we tested whether and how life-long changes in glucose metabolism relate to amyloid-β deposition and Alzheimer's disease-related hypometabolism. Nine healthy young adults (age range: 20-30), 96 cognitively normal older adults (age range: 61-96), and 20 patients with Alzheimer's disease (age range: 50-90) were scanned using fluorodeoxyglucose and Pittsburgh compound B positron emission tomography. Among cognitively normal older subjects, 32 were further classified as amyloid-positive, with 64 as amyloid-negative. To assess the contribution of glucose metabolism to the regional vulnerability to amyloid-β deposition, we defined the highest and lowest metabolic regions in young adults and examined differences in amyloid deposition between these regions across groups. Two-way analyses of variance were conducted to assess regional differences in age and amyloid-β-related changes in glucose metabolism. Multiple regressions were applied to examine the association between amyloid-β deposition and regional glucose metabolism. Both region of interest and whole-brain voxelwise analyses were conducted to complement and confirm the results derived from the other approach. Regional differences in glucose metabolism between the highest and lowest metabolism regions defined in young adults (T = 12.85, P < 0.001) were maintained both in Pittsburgh compound B-negative cognitively normal older subjects (T = 6.66, P < 0.001) and Pittsburgh compound B-positive cognitively normal older subjects (T = 10.62, P < 0.001), but, only the Pittsburgh compound B-positive cognitively normal older subjects group showed significantly higher Pittsburgh compound B retention in the highest compared to the lowest glucose metabolism regions defined in young adults (T = 2.05, P < 0.05). Regional differences in age and amyloid-β-dependent changes in glucose metabolism were found such that frontal glucose metabolism was reduced with age, while glucose metabolism in the precuneus was maintained across the lifespan (right hemisphere: F = 7.69, P < 0.001; left hemisphere: F = 8.69, P < 0.001). Greater Alzheimer's disease-related hypometabolism was observed in brain regions that showed both age-invariance and amyloid-β-related increases in glucose metabolism. Our results indicate that although early and life-long regional variation in glucose metabolism relates to the regional vulnerability to amyloid-β accumulation, Alzheimer's disease-related hypometabolism is more specific to brain regions showing age-invariant glucose metabolism and amyloid-β-related hypermetabolism., (© The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) are both 4 microtubule binding repeat tauopathy related disorders. Clinical trials need new biomarkers to assess the effectiveness of tau-directed therapies. This study investigated the regional distribution of longitudinal diffusion tensor imaging changes, measured by fractional anisotropy, radial and axial diffusivity over 6 months median interval, in 23 normal control subjects, 35 patients with PSP, and 25 patients with CBS. A mixed-effects framework was used to test longitudinal changes within and between groups. Correlations between changes in diffusion variables and clinical progression were also tested. The study found that over a 6 month period and compared to controls, the most prominent changes in PSP were up to 3±1% higher rates of FA reduction predominantly in superior cerebellar peduncles, and up to 18±6% higher rates of diffusivity increases in caudate nuclei. The most prominent changes in CBS compared to controls were up to 4±1% higher rates of anisotropy reduction and 18±6% higher rates of diffusivity increase in basal ganglia and widespread white matter regions. Compared to PSP, CBS was mainly associated with up to 3±1% greater rates of anisotropy reduction around the central sulci, and 11±3% greater rates of diffusivity increase in superior fronto-occipital fascicules. Rates of diffusivity increases in the superior cerebellar peduncle correlated with rates of ocular motor decline in PSP patients. This study demonstrated that longitudinal diffusion tensor imaging measurement is a promising surrogate marker of disease progression in PSP and CBS over a relatively short period.

We believe this is the first study to investigate associations between blood metabolites and neocortical amyloid burden (NAB) in the search for a blood-based biomarker for Alzheimer's disease (AD). Further, we present the first multi-modal analysis of blood markers in this field. We used blood plasma samples from 91 subjects enrolled in the University of California, San Francisco Alzheimer's Disease Research Centre. Non-targeted metabolomic analysis was used to look for associations with NAB using both single and multiple metabolic feature models. Five metabolic features identified subjects with high NAB, with 72% accuracy. We were able to putatively identify four metabolites from this panel and improve the model further by adding fibrinogen gamma chain protein measures (accuracy=79%). One of the five metabolic features was studied in the Alzheimer's Disease Neuroimaging Initiative cohort, but results were inconclusive. If replicated in larger, independent studies, these metabolic features and proteins could form the basis of a blood test with potential for enrichment of amyloid pathology in anti-amyloid trials.

In the past 8 years, both the International Working Group (IWG) and the US National Institute on Aging-Alzheimer's Association have contributed criteria for the diagnosis of Alzheimer's disease (AD) that better define clinical phenotypes and integrate biomarkers into the diagnostic process, covering the full staging of the disease. This Position Paper considers the strengths and limitations of the IWG research diagnostic criteria and proposes advances to improve the diagnostic framework. On the basis of these refinements, the diagnosis of AD can be simplified, requiring the presence of an appropriate clinical AD phenotype (typical or atypical) and a pathophysiological biomarker consistent with the presence of Alzheimer's pathology. We propose that downstream topographical biomarkers of the disease, such as volumetric MRI and fluorodeoxyglucose PET, might better serve in the measurement and monitoring of the course of disease. This paper also elaborates on the specific diagnostic criteria for atypical forms of AD, for mixed AD, and for the preclinical states of AD., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Objective: Cerebrospinal fluid (CSF) neurofilament light chain (NfL) concentration is elevated in neurological disorders, including frontotemporal degeneration (FTD). We investigated the clinical correlates of elevated CSF NfL levels in FTD., Methods: CSF NfL, amyloid-β1-42 (Aβ42), tau, and phosphorylated tau concentrations were compared in 47 normal controls (NC), 8 asymptomatic gene carriers (NC2) of FTD-causing mutations, and 79 FTD (45 behavioral variant frontotemporal dementia [bvFTD], 18 progressive nonfluent aphasia [PNFA], 16 semantic dementia [SD]), 22 progressive supranuclear palsy, 50 Alzheimer disease, 6 Parkinson disease, and 17 corticobasal syndrome patients. Correlations between CSF analyte levels were performed with neuropsychological measures and the Clinical Dementia Rating scale sum of boxes (CDRsb). Voxel-based morphometry of structural magnetic resonance images determined the relationship between brain volume and CSF NfL., Results: Mean CSF NfL concentrations were higher in bvFTD, SD, and PNFA than other groups. NfL in NC2 was similar to NC. CSF NfL, but not other CSF measures, correlated with CDRsb and neuropsychological measures in FTD, but not in other diagnostic groups. Analyses in 2 independent FTD cohorts and a group of autopsy-verified or biomarker-enriched cases confirmed the larger group analysis. In FTD, gray and white matter volume negatively correlated with CSF NfL concentration, such that individuals with the highest NfL levels exhibited the most atrophy., Interpretation: CSF NfL is elevated in symptomatic FTD and correlates with disease severity. This measurement may be a useful surrogate endpoint of disease severity in FTD clinical trials. Longitudinal studies of CSF NfL in FTD are warranted., (© 2014 Child Neurology Society/American Neurological Association.)

The logopenic variant of primary progressive aphasia (PPA) is characterised by impaired sentence repetition and word retrieval difficulties. Post mortem studies, amyloid imaging and CSF tau/Aβ measurements suggest Alzheimer's disease (AD) pathology as the underlying cause. Relatively little is known about patterns of progression in patients with the logopenic variant of PPA. 21 patients (3 with post mortem confirmation of AD and 5 with positive amyloid PIB-PET scans) were studied with longitudinal T1-weighted MR imaging (mean interscan interval 1.2years) using volumetric analysis and voxel-based morphometry (VBM). Baseline imaging showed asymmetrical (left greater than right) involvement of the posterior superior temporal and inferior parietal lobes as well as posterior cingulate and medial temporal lobes. The whole brain rate of volume loss was 2.0% per year with a greater rate of left hemisphere atrophy (2.3%/year) than right hemisphere (1.6%/year). Longitudinal VBM analysis showed increasing involvement of other areas in the left hemisphere (temporal, parietal, frontal and caudate) and atrophy of areas in the right hemisphere that had been involved earlier in the disease in the left hemisphere, particularly posterior cingulate/precuneus. With disease progression there was worsening of anomia, sentence repetition and sentence comprehension but consistent with the spread of imaging changes also deficits in single word comprehension, single word repetition and verbal memory. This study shows that the logopenic variant of PPA remains an asymmetrical disease, with spread through the left hemisphere language network but also involvement to a lesser degree of regions in the right hemisphere that mirror the earlier left hemisphere changes., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Importance: Mutations in the progranulin gene are known to cause diverse clinical syndromes, all attributed to frontotemporal lobar degeneration. We describe 2 patients with progranulin gene mutations and evidence of Alzheimer disease (AD) pathology. We also conducted a literature review., Observations: This study focused on case reports of 2 unrelated patients with progranulin mutations at the University of California, San Francisco, Memory and Aging Center. One patient presented at age 65 years with a clinical syndrome suggestive of AD and showed evidence of amyloid aggregation on positron emission tomography. Another patient presented at age 54 years with logopenic progressive aphasia and, at autopsy, showed both frontotemporal lobar degeneration with TDP-43 inclusions and AD., Conclusions and Relevance: In addition to autosomal-dominant frontotemporal lobar degeneration, mutations in the progranulin gene may be a risk factor for AD clinical phenotypes and neuropathology.

Objective: To compare the diagnostic performance of PET with the amyloid ligand Pittsburgh compound B (PiB-PET) to fluorodeoxyglucose (FDG-PET) in discriminating between Alzheimer disease (AD) and frontotemporal lobar degeneration (FTLD)., Methods: Patients meeting clinical criteria for AD (n = 62) and FTLD (n = 45) underwent PiB and FDG-PET. PiB scans were classified as positive or negative by 2 visual raters blinded to clinical diagnosis, and using a quantitative threshold derived from controls (n = 25). FDG scans were visually rated as consistent with AD or FTLD, and quantitatively classified based on the region of lowest metabolism relative to controls., Results: PiB visual reads had a higher sensitivity for AD (89.5% average between raters) than FDG visual reads (77.5%) with similar specificity (PiB 83%, FDG 84%). When scans were classified quantitatively, PiB had higher sensitivity (89% vs 73%) while FDG had higher specificity (83% vs 98%). On receiver operating characteristic analysis, areas under the curve for PiB (0.888) and FDG (0.910) were similar. Interrater agreement was higher for PiB (κ = 0.96) than FDG (κ = 0.72), as was agreement between visual and quantitative classification (PiB κ = 0.88-0.92; FDG κ = 0.64-0.68). In patients with known histopathology, overall classification accuracy (2 visual and 1 quantitative classification per patient) was 97% for PiB (n = 12 patients) and 87% for FDG (n = 10)., Conclusions: PiB and FDG showed similar accuracy in discriminating AD and FTLD. PiB was more sensitive when interpreted qualitatively or quantitatively. FDG was more specific, but only when scans were classified quantitatively. PiB slightly outperformed FDG in patients with known histopathology.

Patients with corticobasal degeneration (CBD) pathology present with diverse clinical syndromes also associated with other neuropathologies, including corticobasal syndrome, progressive nonfluent aphasia, and an Alzheimer's-type dementia. Some present with behavioral variant frontotemporal dementia (bvFTD), though this subtype still requires more detailed clinical characterization. All patients with CBD pathology and clinical assessment were reviewed (N = 17) and selected if they initially met criteria for bvFTD [bvFTD(CBD), N = 5]. Available bvFTD patients with Pick's [bvFTD(Pick's), N = 5] were selected as controls. Patients were also compared to healthy older controls [N = 53] on neuropsychological and neuroimaging measures. At initial presentation, bvFTD(CBD) showed few neuropsychological or motor differences from bvFTD(Pick's). Neuropsychiatrically, they were predominantly apathetic with less florid social disinhibition and eating disturbances, and were more anxious than bvFTD(Pick's) patients. Voxel-based morphometry revealed similar patterns of predominantly frontal atrophy between bvFTD groups, though overall degree of atrophy was less severe in bvFTD(CBD), who also showed comparative preservation of the frontoinsular rim, with dorsal > ventral frontal atrophy, and sparing of temporal and parietal structures relative to bvFTD(Pick's) patients. Despite a remarkable overlap between the two patient types, bvFTD patients with underlying CBD pathology show subtle clinical features that may distinguish them from patients with Pick's disease neuropathology.

Background/objective: Patients with posterior cortical atrophy (PCA) often have Alzheimer disease (AD) at autopsy, yet are cognitively and anatomically distinct from patients with clinical AD. We sought to compare the distribution of β-amyloid and glucose metabolism in PCA and AD in vivo using Pittsburgh compound B (PiB) and FDG-PET., Methods: Patients with PCA (n = 12, age 57.5 ± 7.4, Mini-Mental State Examination [MMSE] 22.2 ± 5.1), AD (n = 14, age 58.8 ± 9.6, MMSE 23.8 ± 6.7), and cognitively normal controls (NC, n = 30, age 73.6 ± 6.4) underwent PiB and FDG-PET. Group differences in PiB distribution volume ratios (DVR, cerebellar reference) and FDG uptake (pons-averaged) were assessed on a voxel-wise basis and by comparing binding in regions of interest (ROIs)., Results: Compared to NC, both patients with AD and patients with PCA showed diffuse PiB uptake throughout frontal, temporoparietal, and occipital cortex (p < 0.0001). There were no regional differences in PiB binding between PCA and AD even after correcting for atrophy. FDG patterns in PCA and AD were distinct: while both groups showed hypometabolism compared to NC in temporoparietal cortex and precuneus/posterior cingulate, patients with PCA further showed hypometabolism in inferior occipitotemporal cortex compared to both NC and patients with AD (p < 0.05). Patients with AD did not show areas of relative hypometabolism compared to PCA., Conclusions: Fibrillar amyloid deposition in PCA is diffuse and similar to AD, while glucose hypometabolism extends more posteriorly into occipital cortex. Further studies are needed to determine the mechanisms of selective network degeneration in focal variants of AD.

Objectives: In Alzheimer disease (AD), mounting evidence points to a greater role for synaptic loss than neuronal loss. Supporting this notion, multiple postmortem studies have demonstrated that the hippocampal CA1 apical neuropil is one of the earliest sites of pathology, exhibiting tau aggregates and then atrophy before there is substantial loss of the CA1 pyramidal neurons themselves. In this cross-sectional study, we tested whether tissue loss in the CA1 apical neuropil layer can be observed in vivo in patients with mild AD., Methods: We performed ultra-high-field 7-T MRI on subjects with mild AD (n = 14) and age-matched normal controls (n = 16). With a 2-dimensional T2*-weighted gradient-recalled echo sequence that was easily tolerated by subjects, we obtained cross-sectional slices of the hippocampus at an in-plane resolution of 195 μm., Results: On images revealing the anatomic landmarks of hippocampal subfields and strata, we observed thinning of the CA1 apical neuropil in subjects with mild AD compared to controls. By contrast, the 2 groups exhibited no difference in the thickness of the CA1 cell body layer or of the entire CA1 subfield. Hippocampal volume, measured on a conventional T1-weighted sequence obtained at 3T, also did not differentiate these patients with mild AD from controls., Conclusions: CA1 apical neuropil atrophy is apparent in patients with mild AD. With its superior spatial resolution, 7-T MRI permits in vivo analysis of a very focal, early site of AD pathology.

Objective: Posterior cortical atrophy (PCA) and logopenic progressive aphasia (LPA) are clinical syndromes associated with posterior brain atrophy. We compared PCA and LPA to each other and to an age-matched group of patients with early age at onset of Alzheimer disease (EO-AD). We hypothesized that these 3 syndromes are part of a single clinical and biologic continuum., Methods: Voxel-based morphometry (VBM) was used to assess atrophy in 14 PCA, 10 LPA, and 16 EO-AD patients compared to 65 healthy controls. Genetic analysis for APOE was conducted in 30 patients and 44 controls. Four patients came to autopsy. An additional 14 were studied with the beta-amyloid specific PET with tracer (11)C-labeled Pittsburgh Compound-B (PIB)., Results: VBM results demonstrated that, compared to controls, each patient group showed a large area of overlapping atrophy in bilateral parietal, occipital, precuneus, posterior cingulate, posterior temporal, and hippocampal regions. Surrounding this common area, group-specific atrophy was found in small, symptom-specific regions for each group: the right ventral-occipital and superior parietal regions in PCA, the left middle and superior temporal gyri in LPA, and the prefrontal cortex in EO-AD. APOE epsilon4 frequency was higher in all patient groups compared to controls. Four PCA, 5 LPA, and 8 EO-AD patients showed evidence of cortical amyloid at pathology (n = 3) or on PIB-PET (n = 14)., Conclusions: Logopenic progressive aphasia and posterior cortical atrophy showed largely overlapping anatomic and biologic features with early age at onset of Alzheimer disease, suggesting that these clinical syndromes represent the spectrum of clinical manifestation of the nontypical form of Alzheimer disease that presents at an early age.

Although beta-amyloid (Abeta) plaques are a primary diagnostic criterion for Alzheimer's disease, this pathology is commonly observed in the brains of non-demented older individuals. To explore the importance of this pathology in the absence of dementia, we compared levels of amyloid deposition (via 'Pittsburgh Compound-B' (PIB) positron emission tomography (PET) imaging) to hippocampus volume (HV) and episodic memory (EM) in three groups: (i) normal controls (NC) from the Berkeley Aging Cohort (BAC NC, n = 20); (ii) normal controls (NC) from the Alzheimer's disease neuroimaging initiative (ADNI NC, n = 17); and (iii) PIB+ mild cognitive impairment subjects from the ADNI (ADNI PIB+ MCI, n = 39). Age, gender and education were controlled for in each statistical model, and HV was adjusted for intracranial volume (aHV). In BAC NC, elevated PIB uptake was significantly associated with smaller aHV (P = 0.0016) and worse EM (P = 0.0086). Within ADNI NC, elevated PIB uptake was significantly associated with smaller aHV (P = 0.047) but not EM (P = 0.60); within ADNI PIB+ MCI, elevated PIB uptake was significantly associated with both smaller aHV (P = 0.00070) and worse EM (P = 0.046). To further understand these relationships, a recursive regression procedure was conducted within all ADNI NC and PIB+ MCI subjects (n = 56) to test the hypothesis that HV mediates the relationship between Abeta and EM. Significant correlations were found between PIB index and EM (P = 0.0044), PIB index and aHV (P < 0.0001), as well as between aHV and EM (P < 0.0001). When both aHV and PIB were included in the same model to predict EM, aHV remained significant (P = 0.0015) whereas PIB index was no longer significantly associated with EM (P = 0.50). These results are consistent with a model in which Abeta deposition, hippocampal atrophy, and EM occur sequentially in elderly subjects, with Abeta deposition as the primary event in this cascade. This pattern suggests that declining EM in older individuals may be caused by Abeta-induced hippocampus atrophy.

Amyloid imaging represents a major advance in neuroscience, enabling the detection and quantification of pathologic protein aggregations in the brain. In this review we survey current amyloid imaging techniques, focusing on positron emission tomography (PET) with (11)carbon-labelled Pittsburgh Compound-B ((11)C-PIB), the most extensively studied and best validated tracer. PIB binds specifically to fibrillar beta-amyloid (Abeta) deposits, and is a sensitive marker for Abeta pathology in cognitively normal older individuals and patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD). PIB-PET provides us with a powerful tool to examine in vivo the relationship between amyloid deposition, clinical symptoms, and structural and functional brain changes in the continuum between normal aging and AD. Amyloid imaging studies support a model in which amyloid deposition is an early event on the path to dementia, beginning insidiously in cognitively normal individuals, and accompanied by subtle cognitive decline and functional and structural brain changes suggestive of incipient AD. As patients progress to dementia, clinical decline and neurodegeneration accelerate and proceed independently of amyloid accumulation. In the future, amyloid imaging is likely to supplement clinical evaluation in selecting patients for anti-amyloid therapies, while MRI and FDG-PET may be more appropriate markers of clinical progression.

We applied optimised voxel based morphometry (VBM) to brain MRIs from autopsy proven cases of tau positive frontotemporal lobar degeneration (FTLD-T, n = 6), ubiquitin and TDP-43 positive/tau negative FTLD (FTLD-U, n = 8) and cognitively normal controls (n = 61). The analysis revealed that FTLD-T and FTLD-U both show atrophy in the frontal cortex and striatum, but striatal atrophy is more severe in FTLD-T. Manual region of interest tracing of caudate and putamen volumes confirmed the VBM findings. These anatomical differences may help distinguish between FTLD spectrum pathological subtypes in vivo.

To better define the anatomic distinctions between Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD), we retrospectively applied voxel-based morphometry to the earliest magnetic resonance imaging scans of autopsy-proven AD (N = 11), FTLD (N = 18), and controls (N = 40). Compared with controls, AD patients showed gray matter reductions in posterior temporoparietal and occipital cortex; FTLD patients showed atrophy in medial prefrontal and medial temporal cortex, insula, hippocampus, and amygdala; and patients with both disorders showed atrophy in dorsolateral and orbital prefrontal cortex and lateral temporal cortex (P(FWE-corr) < .05). Compared with FTLD, AD patients had decreased gray matter in posterior parietal and occipital cortex, whereas FTLD patients had selective atrophy in anterior cingulate, frontal insula, subcallosal gyrus, and striatum (P < .001, uncorrected). These findings suggest that AD and FTLD are anatomically distinct, with degeneration of a posterior parietal network in AD and degeneration of a paralimbic fronto-insular-striatal network in FTLD.

Objective: To compare the in vivo uptake of two amyloid-binding PET agents, PIB and FDDNP, in human subjects with a prion protein (PrP) gene (PRNP) mutation that produces a clinical syndrome similar to Alzheimer disease (AD)., Background: Amyloid imaging with specific PET ligands offers great promise for early detection and differential diagnosis of AD. Genetic forms of prion disease can present with clinical features that resemble AD, and at autopsy may show deposition of mutant PrP-amyloid. FDDNP binds to PrP-amyloid in postmortem human specimens, but has not been reported in vivo in prion disease. The ability of PIB to bind PrP-amyloid is not known., Methods: Two brothers with a 6 octapeptide repeat insertion mutation (6-OPRI) in the PRNP gene underwent clinical, structural MRI, and FDG-PET evaluations. One brother received a PIB-PET evaluation, while the other received an FDDNP-PET scan. PET results were compared with five normal subjects and five individuals with AD scanned with either agent., Results: PIB uptake was similar to controls in one brother, while FDDNP uptake was intermediate between AD and controls in the other brother., Conclusions: Different amyloid-binding agents may have differential sensitivity to prion-related brain pathology. A combination of amyloid imaging agents may be useful in the diagnosis of early-onset dementia.