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BackgroundIndividuals with Down syndrome (DS) are at high risk for dementia, specifically Alzheimer's disease. However, many measures regularly used for the detection of dementia in the general population are not suitable for individuals with DS due in part to floor effects. Some measures, including the Severe Impairment Battery (SIB), Brief Praxis Test (BPT) and Dementia Scale for People with Learning Disabilities (DLD), have been used in clinical trials and other research with this population. Validity research is limited, particularly regarding the use of such tools for detection of prodromal dementia in the DS population. The current project presents baseline cross-sectional SIB, BPT and DLD performance in order to characterise their predictive utility in discriminating normal cognition, possible dementia and probable dementia in adult DS.MethodBaseline SIB, BPT and DLD performances from 100 individuals (no dementia=68, possible dementia=16 & probable dementia=16) were examined from a longitudinal cohort of aging individuals with DS. Receiver operating characteristic curves investigated the accuracy of these measures in relation to consensus dementia diagnoses, diagnoses which demonstrated high percent agreement with the examining neurologist's independent diagnostic impression.ResultsThe SIB and BPT exhibited fair discrimination ability for differentiating no/possible versus probable dementia [area under the curve (AUC)=0.61 and 0.66, respectively]. The DLD exhibited good discrimination ability for differentiating no versus possible/probable dementia (AUC=0.75) and further demonstrated better performance of the DLD Cognitive subscale compared with the DLD Social subscale (AUC=0.77 and 0.67, respectively).ConclusionsResults suggest that the SIB, BPT and DLD are able to reasonably discriminate consensus dementia diagnoses in individuals with DS, supporting their continued use in the clinical assessment of dementia in DS. The general performance of these measures suggests that further work in the area of test development is needed to improve on the AUCs for dementia status discrimination in this unique population. At present, however, the current findings suggest that the DLD may be the best option for reliable identification of prodromal dementia in this population, reinforcing the importance of including informant behaviour ratings in assessment of cognition for adults with DS.

One major obstacle to the accurate diagnosis of ADHD in college students is malingering, although many symptom self-report measures used in the diagnostic process do not contain validity scales to identify feigners. The Infrequency Index (CII) for the Conners’ Adult ADHD Rating Scale–Self-Report: Long Version (CAARS-S: L) was developed in response to this concern, although further validation of this index is needed. Another topic of interest in ADHD malingering research is the increasing use of online assessments. However, little is known about how ADHD is malingered in an online format, particularly on the CAARS-S: L. The current study utilized a coached simulation design to examine the feigning detection accuracy of the CII and provide initial results on the effect of administration format (paper vs. online) on CAARS-S: L profiles. Data from 139 students were analyzed. Students with ADHD and students instructed to feign the disorder produced statistically comparable elevations on seven of eight CAARS-S: L clinical scales. Clinical scale elevations were generally comparable between paper and online forms, although some differences in the clinical and simulated ADHD groups suggest the need for further research. The CII demonstrated modest sensitivity (0.36) and adequate specificity (0.85) at the recommended cut score across administration formats. Specificity reached desirable levels (>= .90) at a raised cut score. These values were similar across administration formats. Results support the use of the CII and online CAARS-S: L form

Summary Background Adults with Down syndrome are at an ultra-high risk of Alzheimer's disease, but diagnosis of Alzheimer's disease in this population is challenging. We aimed to validate the clinical utility of plasma neurofilament light chain (NfL) for the diagnosis of symptomatic Alzheimer's disease in Down syndrome, assess its prognostic value, and establish longitudinal changes in adults with Down syndrome. Methods We did a multicentre cohort study, including adults with Down syndrome (≥18 years), recruited from six hospitals and university medical centres in France, Germany, Spain, the UK, and the USA, who had been assessed, followed up, and provided at least two plasma samples. Participants were classified by local clinicians, who were masked to biomarker data, as asymptomatic (ie, no clinical suspicion of Alzheimer's disease), prodromal Alzheimer's disease, or Alzheimer's disease dementia. We classified individuals who progressed along the Alzheimer's disease continuum during follow-up as progressors. Plasma samples were analysed retrospectively; NfL concentrations were measured centrally using commercial kits for biomarker detection. We used ANOVA to evaluate differences in baseline NfL concentrations, Cox regression to study their prognostic value, and linear mixed models to estimate longitudinal changes. To account for potential confounders, we included age, sex, and intellectual disability as covariates in the analyses. Findings Between Aug 2, 2010, and July 16, 2019, we analysed 608 samples from 236 people with Down syndrome: 165 (70%) were asymptomatic, 32 (14%) had prodromal Alzheimer's disease, and 29 (12%) had Alzheimer's disease dementia; ten [4%] participants were excluded because their classification was uncertain. Mean follow-up was 3·6 years (SD 1·6, range 0·6–9·2). Baseline plasma NfL concentrations showed an area under the receiver operating characteristic curve of 0·83 (95% CI 0·76–0·91) in the prodromal group and 0·94 (0·90–0·97) in the dementia group for differentiating from participants who were asymptomatic. An increase of 1 pg/mL in baseline NfL concentrations was associated with a 1·04-fold risk of clinical progression (95% CI 1·01–1·07; p=0·0034). Plasma NfL concentrations showed an annual increase of 3·0% (95% CI 0·4–5·8) per year in the asymptomatic non-progressors group, 11·5% (4·9–18·5) per year in the asymptomatic progressors group, and 16·0% (8·4–24·0) per year in the prodromal Alzheimer's disease progressors group. In participants with Alzheimer's disease dementia, NfL concentrations increased by a mean of 24·3% (15·3–34·1). Interpretation Plasma NfL concentrations have excellent diagnostic and prognostic performance for symptomatic Alzheimer's disease in Down syndrome. The longitudinal trajectory of plasma NfL supports its use as a theragnostic marker in clinical trials. Funding AC Immune, La Caixa Foundation, Instituto de Salud Carlos III, National Institute on Aging, Wellcome Trust, Jerome Lejeune Foundation, Medical Research Council, National Institute for Health Research, EU Joint Programme–Neurodegenerative Disease Research, Alzheimer's society, Deutsche Forschungsgemeinschaft, Stiftung fur die Erforschung von Verhaltens und Umwelteinflussen auf die menschliche Gesundheit, and NHS National Institute of Health Research Applied Research Collaborations East of England, UK.

Objective:To determine whether primitive reflexes serve as an indicator of dementia in adults with Down syndrome (DS), we collected neurologic examination data, cognitive and behavioral assessments, and clinical consensus diagnoses of dementia from 92 adults with DS.Methods:In a cross-sectional, observational study of a regional cohort, chi-square and Fisher’s exact tests examined individual reflexes across diagnostic group (No, Possible, or Probable Dementia). In 64 participants with all 8 reflexes assessed, the number of primitive reflexes was assessed as a predictor of diagnosis using age-controlled multinomial logistic regression and of performance on clinical assessments (Brief Praxis Test [BPT], Severe Impairment Battery [SIB], and the Dementia Questionnaire for People with Learning Disabilities [DLD] using age-adjusted linear regression.Results:Primitive palmomental, grasp, snout, and suck reflexes were more frequent in individuals with probable dementia, but all participants showed at least one primitive reflex. Multiple primitive reflexes in combination served as a better indicator of dementia, with each additional abnormal reflex tripling probability of Probable Dementia group membership controlling for age. Abnormal reflex count was not associated with direct assessment of cognition and praxis (SIB and BPT) but associated with informant ratings of cognitive and behavioral functioning (DLD).Conclusions:The presence of multiple reflexes serves as an indicator of dementia status in DS as a supplement to direct assessment of cognition and praxis. The reflex examination may serve as a tool in the multimethod evaluation for dementia in DS, as it appears unaffected by intellectual disability and language mastery.

Author(s): Koehl, Lisa; Harp, Jordan; Van Pelt, Kathryn L; Head, Elizabeth; Schmitt, Frederick A | Abstract: IntroductionEarly detection ofndementia symptoms is critical in Down syndrome (DS)nbutncomplicated by clinical assessmentnbarriers. The current study aimed to characterize cognitive and behavioral impairment using longitudinal trajectories comparing several measures of cognitive and behavioral functioning.MethodsMeasures included global cognitive status (Severe Impairment Battery [SIB]), motor praxis (Brief Praxis Test [BPT]), and clinical dementia informant ratings (Dementia Questionnaire for People with Learning Disabilities [DLD]). One-year reliability was assessed using a two-way mixed effect, consistency, single measurement intraclass correlation among non-demented participants. Longitudinal assessment of SIB, BPT, and DLD was completed using linear mixed effect models.ResultsOne-year reliability (n = 52; 21 male) was moderate for DLD (0.69 to 0.75) and good for SIB (0.87) and BPT (0.80). Longitudinal analysis (n = 72) revealed significant age by diagnosis interactions for SIB (F(2, 115.02) = 6.06, P = .003), BPT (F(2, 85.59) = 4.56, P = .013), and DLD (F(2, 103.56) = 4.48, P = .014). SIB progression (PR) had a faster decline in performance versus no-dementia (ND) (t(159) = -2.87; P = .013). Dementia had a faster decline in BPT performance versus ND (t(112) = -2.46; P = .041). PR showed quickly progressing scores compared to ND (t(128) = -2.86; P = .014).DiscussionCurrent measures demonstrated moderate to good reliability. Longitudinal analysis revealed that SIB, BPT, and DLD changed with age depending on diagnostic progression; no change rates were dependent on baseline cognition, indicating usefulness across a variety of severity levels in DS.

Author(s): Van Pelt, Kathryn L; Koehl, Lisa; Caban-Holt, Allison; Anderson-Mooney, Amelia; Head, Elizabeth; Schmitt, Frederick A | Abstract: IntroductionThe striatum and frontal lobes have been shown to have early Alzheimer's disease (AD) neuropathology and are critical for motor and cognitive function. We hypothesized gait would be associated with early-stage dementia in Down syndrome (DS), a cohort at risk for AD.MethodsTwenty-eight participants with DS were enrolled in the study. Participants walked at their self-selected pace and while completing a dual task (counting, obstacle, or counting+obstacle).ResultsAll participants were able to complete the self-paced condition and 78.57-96.42% completed the dual-task conditions. There was a trend for greater dual-task effects on gait velocity based on dementia diagnosis. Gait velocity had stronger associations with clinical dementia assessments than age or diagnosis.DiscussionA dual-task gait paradigm is feasible to conduct with adults with DS and is associated with age and cognitive impairment. Dual-task gait may serve as an indicator of early stage dementia in DS.

Anti-N-methyl-D-aspartate receptor encephalitis is a neurological, autoimmune disorder tightly conceptualized only as recently as the mid-2000s. It presents itself in a combination of psychiatric, neurological, and autonomic features. We observe a unique case with probable earlier episode (prior to the mid-2000s conceptualization of the disease) and a later relapse, accompanying a comprehensive neuropsychological profile tracked after the relapse and subsequent improvement. Neurocognitive findings revealed residual frontal deficits with mood changes even in the state after plasmapheresis. This case is the first to describe posttreatment cognition in anti-NMDAR encephalitis after probable serial autoimmune episodes.