Search

Many virological tests have been implemented during the Coronavirus Disease 2019 (COVID-19) pandemic for diagnostic purposes, but they appear unsuitable for screening purposes. Furthermore, current screening strategies are not accurate enough to effectively curb the spread of the disease. Therefore, the present study was conducted within a controlled clinical environment to determine eventual detectable variations in the voice of COVID-19 patients, recovered and healthy subjects, and also to determine whether machine learning-based voice assessment (MLVA) can accurately discriminate between them, thus potentially serving as a more effective mass-screening tool. Three different subpopulations were consecutively recruited: positive COVID-19 patients, recovered COVID-19 patients and healthy individuals as controls. Positive patients were recruited within 10 days from nasal swab positivity. Recovery from COVID-19 was established clinically, virologically and radiologically. Healthy individuals reported no COVID-19 symptoms and yielded negative results at serological testing. All study participants provided three trials for multiple vocal tasks (sustained vowel phonation, speech, cough). All recordings were initially divided into three different binary classifications with a feature selection, ranking and cross-validated RBF-SVM pipeline. This brough a mean accuracy of 90.24%, a mean sensitivity of 91.15%, a mean specificity of 89.13% and a mean AUC of 0.94 across all tasks and all comparisons, and outlined the sustained vowel as the most effective vocal task for COVID discrimination. Moreover, a three-way classification was carried out on an external test set comprised of 30 subjects, 10 per class, with a mean accuracy of 80% and an accuracy of 100% for the detection of positive subjects. Within this assessment, recovered individuals proved to be the most difficult class to identify, and all the misclassified subjects were declared positive; this might be related to mid and short-term vocal traces of COVID-19, even after the clinical resolution of the infection. In conclusion, MLVA may accurately discriminate between positive COVID-19 patients, recovered COVID-19 patients and healthy individuals. Further studies should test MLVA among larger populations and asymptomatic positive COVID-19 patients to validate this novel screening technology and test its potential application as a potentially more effective surveillance strategy for COVID-19. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is characterized by loss of dopaminergic neurons in the substantia nigra pars compacta, inducing dopaminergic depletion in the striatum. Recently, subcortical nuclei shape analysis based on T1 imaging has been used in PD pathology. The present study aimed to test the hypothesis that changes in local volume detectable with T1-weighted imaging are concomitant with PD and may be used as biomarkers. We compared 21 PD patients and 20 control subjects using gray matter density and subcortical nuclei volume and shape. We also tested correlations between these parameters and clinical scales. A linear discriminant analyses was carried out using global volume and local atrophy. The differences revealed between the 2 groups were volume differences in the putamen and shape differences in the putamen and the caudate nucleus. A correlation was found between shape and motor symptoms. The discriminant analysis performed using local atrophy values led to the best classification. Our results show that shape analysis contributes valuable information to investigations concerning PD patients and helps to discriminate these patients from control subjects. [ABSTRACT FROM AUTHOR]

Abstract: Giannantoni A, Silvestro D, Siracusano S, Azicnuda E, D''Ippolito M, Rigon J, Sabatini U, Bini V, Formisano R. Urologic dysfunction and neurologic outcome in coma survivors after severe traumatic brain injury in the postacute and chronic phase. Objectives: To investigate voiding dysfunction and upper urinary tract status in survivors of coma resulting from traumatic brain injury (TBI), and to compare clinical and urodynamic results with neurologic and psychological features as well as functional outcomes. Design: Observational study focused on urologic dysfunction and neurologic outcome in coma survivors after traumatic brain injury in the postacute and chronic phase. Setting: A postcoma unit in a rehabilitation hospital. Participants: Consecutive patients (N=57) who recovered from coma of traumatic etiology and who were admitted during a 1-year period to a postcoma unit of a rehabilitation hospital. Interventions: Patients underwent clinical urologic assessment, urodynamics with the assessment of the Schafer nomogram and the projected isovolumetric detrusor pressure to evaluate detrusor contractility, ultrasound assessment of the lower and upper urinary tract and voiding cystourethrography, routinely performed, according to the International Continence Society Standards. Neurologic variables assessed were brain injury and disability severity, and neuropsychological status. Neuroimaging identified the site of cerebral lesions. Main Outcome Measures: Urinary symptoms, disability by means of the Glasgow Outcome Scale (GOS), and neuropsychological status by means of the Neurobehavioral Rating Scale (NBRS), and the relationships among them. Results: Of the 57 patients studied, 30 had overactive bladder (urge incontinence) symptoms, 28 had detrusor overactivity, and 18 had detrusor underactivity with associated pseudodyssynergia in 15 of these patients. Eleven patients had hypertrophic bladder; 3, bilateral pyelectasia; and 2, vesicoureteral reflux. Disability measured by GOS was severe in 8 patients and moderate in 27, while recovery was good in 22 patients. The mean NBRS total score indicated a mild cognitive impairment. Neuroimaging showed diffuse brain injury in all patients. Statistically significant relationships were found between urge incontinence, detrusor overactivity, and poor neurologic functional outcome, between detrusor overactivity and right hemisphere damage (P=.0001), and between impaired detrusor contractility and left hemisphere injuries (P=.0001). Conclusions: Most patients who recovered from coma resulting from TBI have symptoms of overactive bladder syndrome and voiding difficulties. These urinary problems correlate with cerebral involvement and neurologic functional outcome. [Copyright &y& Elsevier]

Abstract: The present work explores the possibility of localizing veins with magnetic resonance venography using susceptibility weighted imaging. It also seeks new approaches, directed by the spatial specificity of activated brain regions, that have sufficient precision for practical use in functional MRI studies. A 3D flow compensated multiple gradient echo sequence, featuring optimized T2* weighting within a reasonable time of acquisition (11 min) and a small voxel size (0.5×0.5×1 mm3), was used to acquire MR images at 3 T. Post-processing consisted of homodyne filtering, linear phase scaling and magnitude masking prior to minimum intensity projection (mIP). The multiple echo approach provided a satisfactory (48±7%) increase in signal-to-noise ratio with respect to conventional methods. Specific features of the blood oxygenation level-dependent phase effect were simulated and used for designing and exploring different phase masking methods in relation to vessel morphology and MRI voxel geometry. As with simulations, the best results were obtained with an asymmetric triangular phase masking, featuring an improved venographic contrast without any increase in the full-width at half-maximum. The multiple echo approach provided satisfactory vessel localization capacity by using asymmetric triangular phase masking and a 4-mm-thick mIP. The venographic contrast obtained enabled the detection of vessels with diameter down to approximately 500 μm, suggesting the applicability of the proposed method as an additional technique in fMRI studies. [Copyright &y& Elsevier]

• Pediatric Huntington disease (PHD) with Highly Expanded (HE) CAG mutations affects brain and peripheral organs. • The liver is one affected peripheral organ showing steatosis in HE-PHD. • Higher the mutation size in HE-PHD, earlier the liver steatosis in childhood HD life. [ABSTRACT FROM AUTHOR]

Objective: Several evidences demonstrated the role of white matter (WM) lesions in the pathogenesis of Vascular Parkinsonism (VP), a clinical entity characterized by parkinsonism, postural instability, marked gait difficulty and poor response to levodopa. However, the involvement of normal appearing white matter (NAWM) in VP still remains unknown. This study aimed to investigate the microstructural integrity of NAWM in VP compared to Parkinson's disease (PD) and controls using neuroimaging approach.Methods: Magnetic resonance imaging data were acquired from 50 participants (15 VP, 20 PD and 15 controls). Diffusion tensor imaging (DTI) and Tract-based spatial statistics (TBSS) were performed to assess microstructural NAWM changes. In order to evaluate the relationship between specific fiber tract involvement and clinical picture, diffusion alterations were correlated with clinical features.Results: Compared to PD patients and controls, significantly reduced fractional anisotropy (FA) and increased mean diffusivity (MD) and radial diffusivity (RD) in NAWM of corpus callosum, internal and external capsule, and corona radiata were present in VP. By contrast, DTI metrics were normal in NAWM-PD and controls. A significant correlation was found between FA and MD of anterior third of corpus callosum and clinical variables (postural instability, freezing-of-gait and symmetry of parkinsonism).Conclusions: This study improves the knowledge on WM pathology in VP, as our results demonstrate that NAWM damage occurs in VP, but not in PD nor in controls. NAWM damage might relate to clinical picture and suggest that non-clearly-visible WM alterations may contribute to the physiopathology of this vascular disease. [ABSTRACT FROM AUTHOR]

Introduction: We investigated the imaging counterpart of two functional domains (ocular motor dysfunction and postural instability) in progressive supranuclear palsy (PSP) patients classified according to the new clinical diagnostic criteria.Methods: Forty-eight patients with probable PSP-Richardson's syndrome (PSP-RS), 30 with probable PSP-parkinsonism (PSP-P), 37 with Parkinson's disease (PD), and 38 controls were enrolled. For each functional domain, PSP patients were stratified by two certainty levels: vertical supranuclear gaze palsy (O1) and slowness of vertical saccades (O2) for ocular motor dysfunction; early unprovoked falls and tendency to fall on the pull-test for postural instability. Voxel-based morphometry (VBM), whole-brain fractional anisotropy (FA) and MR planimetric measurements were analysed and compared across patient groups.Results: O1 was present in 64%, and O2 in 36% of all PSP patients. All PSP-RS patients showed early unprovoked falls. TBSS whole-brain analysis revealed that superior cerebellar peduncles (SCPs) were the only structures with significantly lower FA values in PSP-RS compared with PSP-P patients. PSP/O1 patients had lower FA values in midbrain than PSP/O2 patients. By contrast, VBM revealed no differences in grey matter volume between PSP patient groups. MR Planimetric measurements confirmed atrophy of midbrain and SCPs, in line with DTI findings.Conclusions: Our study demonstrates that SCPs were significantly more damaged in patients with PSP-RS in comparison with PSP-P patients, thus suggesting the role of SCPs in developing postural instability. Midbrain damage was less severe in O2 than in O1 patients, suggesting that the degree of vertical ocular dysfunction reflects the severity of midbrain atrophy. [ABSTRACT FROM AUTHOR]

Introduction: Several structural and functional neuroimaging studies have shown that the Supplementary Motor Area (SMA) is affected by tau pathology in patients with Progressive Supranuclear Palsy (PSP). The aim of the study was to investigate the biochemical profile of SMA in PSP patients, using proton magnetic resonance spectroscopy (1H-MRS).Methods: Sixteen PSP patients and 18 healthy controls participated in this study. 1H-MRS was performed by using a Point RESolving Spectroscopy (PRESS) single-voxel sequence implemented on a 3-T scanner. A voxel of 25 × 25 × 15 mm involving the right and left SMA was acquired in all subjects. Peak areas of N-acetyl-aspartate + N-acetyl-aspartyl-glutamate (NAA), creatine with phosphocreatine (Cr), glycerophosphocholine + phosphocholine (Cho), glutamate + glutamine (Glx), glutathione (GSH), myo-Inositol (mI) and Scyllo-Inositol (Scyllo) were calculated using a version 6.3-1K of the fitting program LCModel. Comparative analysis was performed on both absolute concentrations and ratio values relative to Cr.Results: PSP patients showed a significant decrease in Scyllo concentration and Scyllo/Cr ratio values in SMA, compared to controls, whereas no difference between groups was found for the other ratio values. Of note, the attention and working memory functions were positively related to Scyllo and Scyllo/Cr values in PSP patients.Conclusions: Our study demonstrates that Scyllo and Scyllo/Cr were significantly reduced in the SMA of PSP patients. Because Scyllo seems to be able to protect against formation of toxic fibrils of amyloid-beta fragments and tau oligomers deposition, these preliminary findings may open new perspectives to investigate Scyllo as a new potential disease-modifying therapy for PSP. [ABSTRACT FROM AUTHOR]

Background: Huntington's disease is a rare, neurodegenerative disease caused by an expanded CAG repeat mutation in the huntingtin gene. Compared with adult-onset Huntington's disease, juvenile Huntington's disease (onset ≤20 years) is even rarer and has not been studied extensively. We aimed to further characterise juvenile Huntington's disease by examining the effect of CAG repeat size on disease presentation, progression, and survival.Methods: We did a retrospective analysis of patients with juvenile Huntington's disease aged 20 years or younger, according to the length of their CAG repeat and who had disabling psychiatric symptoms (with motor symptoms) or motor symptoms alone, and of patients with adult-onset Huntington's disease manifesting aged 30-60 years with 40 or more CAG repeats, from the REGISTRY and ENROLL-HD platforms and from two institutional databases (Lega Italiana Ricerca Huntington Foundation and the Instituto Neurociencias de Buenos Aires and the Sanatorio de la Trinidad Mitre). Patients with psychiatric but no motor symptoms were excluded. We compared symptoms at onset and longitudinally in patients with juvenile Huntington's disease with highly expanded (HE subgroup) or low expansion (LE subgroup) mutations, grouped by hierarchical clustering analysis. We also compared disease progression (longitudinal change in Unified Huntington's Disease Rating Scale-Total Motor Score) and survival of patients with juvenile and adult-onset Huntington's disease.Findings: We extracted medical records from 580 patients entered into the studies or databases between June 23, 2004, and March 31, 2018, of whom 36 patients met our definition of juvenile Huntington's disease and 197 for adult-onset Huntington's disease. According to caregiver reports, gait disturbance was more often a first presenting symptom in the HE subgroup (eight [80%] of 10 patients) than in the LE subgroup (seven [27%] of 26 patients; p=0·0071), whereas loss of hand dexterity was more common in the LE subgroup (11 [42%] of 26 patients) than in the HE subgroup (0 [0%] of 10 patients; p=0·0160). Compared with the LE subgroup, development delay (0 [0%] in the LE subgroup vs nine [90%] in the HE subgroup; p<0·0001), severe gait impairment (nine [35%] in the LE subgroup vs nine [90%] in the HE subgroup; p=0·0072), and seizures (three [11%] in the LE subgroup vs eight [80%] in the HE subgroup; p<0·0001) prevailed over time in the HE subgroup. Disease progression was more rapid in juvenile Huntington's disease (n=14) than in adult-onset Huntington's disease (n=52; generalised estimating equation model, p=0·0003). Of 121 deceased patients, median survival was shorter in the juvenile Huntington's disease (n=17) cohort than in adult-onset Huntington's disease (n=104) cohort (hazard ratio 2·18 [95% CI 1·08-4·40]; p=0·002).Interpretation: Patients with HE juvenile Huntington's disease differ clinically from patients with LE juvenile Huntington's disease or adult-onset Huntington's disease, suggesting reclassification of this particularly aggressive form of Huntington's disease might be required.Funding: Lega Italiana Ricerca Huntington Foundation and IRCCS Ospedale Casa Sollievo della Sofferenza. [ABSTRACT FROM AUTHOR]

Introduction: Differentiating clinically progressive supranuclear palsy-parkinsonism (PSP-P) from Parkinson's disease (PD) may be challenging, especially in the absence of vertical supranuclear gaze palsy (VSGP). The Magnetic Resonance Parkinsonism Index (MRPI) has been reported to accurately distinguish between PSP and PD, yet few data exist on the usefulness of this biomarker for the differentiation of PSP-P from PD.Methods: Thirty-four patients with PSP-P, 46 with PSP-Richardson's syndrome (PSP-RS), 53 with PD, and 53 controls were enrolled. New consensus criteria for the clinical diagnosis of PSP were used as the reference standard. The MRPI, and a new index termed MRPI 2.0 including the measurement of the third ventricle width (MRPI multiplied by third ventricle width/frontal horns width ratio), were calculated on T1-weighted MR images.Results: The MRPI differentiated patients with PSP-P from those with PD with sensitivity and specificity of 73.5% and 98.1%, respectively, while the MRPI 2.0 showed higher sensitivity (100%) and similar specificity (94.3%) in differentiating between these two groups. Both biomarkers showed excellent performance in differentiating PSP-P patients with VSGP from those with PD, but the MRPI 2.0 was much more accurate (95.8%) than MRPI in differentiating PSP-P patients with slowness of vertical saccades from PD patients.Conclusion: The MRPI 2.0 accurately differentiated PSP-P patients from those with PD. This new index was more powerful than MRPI in differentiating PSP patients in the early stage of the disease with slowness of vertical saccades from patients with PD, thus helping clinicians to consolidate the diagnosis based on clinical features, in vivo. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to investigate the thalamic biochemical profile in patients with essential tremor (ET), using proton magnetic resonance spectroscopy (1H-MRS), and to explore the correlations between clinical and biochemical data.Methods: Sixteen patients with ET and 14 healthy controls participated in this study. After conventional MR imaging, single-voxel 1H-MRS (TR = 2000 ms; TE = 28 ms) was performed by using a PROBE-SV system implemented on a 3-T scanner. A voxel of 10 × 10 × 15 mm involving the ventrointermediate (Vim) nucleus was acquired in each thalamus of all subjects. Peak areas of N-acetyl-aspartate + N-acetyl-aspartyl-glutamate (NAA), creatine + phosphocreatine (Cr), glycerophosphocholine + phosphocholine (Cho), and glutamate + glutamine (Glx) were calculated using a version 6.3-1 K of the fitting program LCModel for each voxel. Comparative and correlation analyses were performed on the NAA, Cr, Cho, and Glx concentrations, as well as on the values of the NAA/Cr, a neural density marker, Cho/Cr, a membrane marker, and Glx/Cr, an intracellular neurotransmitter marker.Results: Patients with ET showed a significant increase in Glx concentration and Glx/Cr ratio values in both thalami, compared to healthy controls, whereas no difference inter-group was found for the other metabolites and NAA/Cr and Cho/Cr ratio values. Of note, the tremor severity was positively related to increased Glx concentrations and Glx/Cr ratio values in ET group.Conclusions: Our study shows that 1H-MRS can highlight in vivo metabolic abnormalities in the thalami of ET patients, supporting the evidence that the increase of thalamic glutamatergic transmission can play a role in developing of tremor in ET. [ABSTRACT FROM AUTHOR]

Introduction: The objective of this study was to investigate the thalamic biochemical changes in tremor-dominant Parkinson's disease (tPD) patients in comparison with essential tremor with resting tremor (rET) patients, by using proton MR spectroscopy (1H-MRS).Methods: Fourteen tPD patients, 12 rET patients and 10 controls participated in this study. All patients underwent dopamine transporter single-photon emission computed tomography (DAT-SPECT) with 123I-ioflupane, and a short-echo single-voxel 1H-MRS on a 3T scanner. A voxel of 10 × 15 × 10 mm involving the Vim nucleus was acquired in both thalami of all subjects. Peak areas of N-acetyl-aspartate (NAA), creatine (Cr), glycerophosphocholine (Cho), and glutamate (Glu) were measured for each voxel using LCModel. The NAA/Cr, Cho/Cr, and Glu/Cr ratios were then calculated.Results: DAT-SPECT was abnormal in tPD patients, whereas it was normal in rET patients. Patients with tPD showed a significant reduction of NAA/Cr and Cho/Cr in the thalami compared to rET and healthy controls; whereas there were no significant differences between rET patients and controls. The combination of thalamic NAA/Cr and Cho/Cr ratios showed a 100% accuracy in distinguishing tPD patients from rET patients and controls.Conclusions: This study provides preliminary evidence that thalamic neurometabolic abnormalities occur in tremor-dominant phenotype of PD, and suggests that 1H-MRS can help differentiate patients with tPD from those with rET. [ABSTRACT FROM AUTHOR]

Ongoing signals from one׳s own body (interoception) allow experience of self-feeling. In early studies interoception strictly referred to the awareness of visceral sensation but recent theories have expanded this concept to denote the ongoing status of the body. Here we asked left and right focal brain-damaged patients to answer questions about their interoceptive feelings, and correlated their responses to a quantitative measure of their lesions (voxel-based symptom-lesion mapping). By these means we could reveal that three key structures contribute to building up the feeling of self, namely insula (interoceptive modulator), amygdala (emotional modulator) and putamen (motor modulator). This brain network may be necessary for the integrity of self-feeling. A dysfunction of this network might impair perception of the inner body state, and also account for psychological disturbances, such as the somatic symptom disorders, in which individuals experience subjective symptoms suggesting physical illness or injury despite medical test results which are normal, and clinical examination do not disclose relevant medical conditions. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Bone mineral density (BMD) result has a low predictive value on patients' risk for future fractures. Thus, new approaches for examining patients at risk for developing osteoporosis would be desirable. Magnetic resonance (MR) investigations in cancellous bone have been shown to yield useful quantitative information on both trabecular-bone microstructure and bone marrow composition. This work was undertaken to address the hypothesis that the effective internal magnetic field gradient (IMFG), a new MR parameter, discriminates between healthy, osteopenic and osteoporotic postmenopausal women, classified on the basis of bone mineral density (BMD) criteria. The work builds on preliminary results indicating that IMFG, measured in trabecular-bone pores and quantified by spin-echo decay and water diffusion MR near the bone–bone marrow interface depends on both the bone marrow water rate of diffusion and the magnetic susceptibility difference (ΔX) between water and bone. Materials and methods: MR relaxometry, MR spectroscopy and diffusion-weighted MR imaging of the heel was performed in fifty-five women (mean age, 62.9±6.6years) at 3T. Moreover, in order to study the reproducibility of IMFG measurement, five young women (mean age 31.0±3.2years; age range, 28–36years) were scanned and rescanned. The study protocol was approved by the local Ethics Committee. Quantitative Computer Tomography (QCT) of the L1–L3 vertebral segments was performed to classify the postmenopausal women into three groups according to QCT BMD: healthy (n=8); osteopenic (n=25); and osteoporotic (n=22). In all subjects, BMD T-scores, marrow fat content (Mfc), T2*, apparent diffusion coefficient (ADC) and IMFG (estimated from the additional spin-echo decay due to diffusion of water in local magnetic field gradients), were assessed in the whole calcaneus as well as in three calcaneal subregions: subtalar, tuber calcaneus, and cavum calcaneus. Between-group comparisons to assess group differences and Pearson correlation analysis were performed. Short and long-term coefficients of variation (CVS and CVL, respectively) were evaluated in young subjects. Results: Reproducibility of the IMFG measurement was satisfactory. No significant difference was found in the IMFG measurement performed in both calcaneus and subtalar calcaneal region between the two separate sessions comprised of five young women. Mfc did not significantly differ between groups. The IMFG in the subtalar region was significantly different between all three groups (P <0.01), being greatest in healthy women, intermediate in those with osteopenia, and lowest in osteoporotic subjects. Conversely neither T2* nor ADC is able to discriminate healthy subjects from those with osteopenia and osteoporosis. Increased inter-trabecular space, as it typically occurs in patients with osteoporosis, modifies water diffusion, conferring higher ADC values, thereby lowering the IMFG. Conclusion: The IMFG measured in the calcaneal subtalar region shows a high ability in identifying healthy subjects. The new quantitative MR method based on measurement of the IMFG may provide a new means for assessing patients with osteoporosis. [Copyright &y& Elsevier]

Abstract: Emotion or stress can jeopardize decision-making relevance and cognitive functioning. In this paper we examine plan continuation error (PCE), an erroneous behavior defined as a “failure to revise a flight plan despite emerging evidence that suggests it is no longer safe” (Orasanu et al., 2001). Our hypothesis is that negative emotional consequences attached to the go-around decision provoke a temporary impairment of the decision-making process and favor PCE. We investigated this hypothesis with a simplified landing task in which two possible contributors to those emotions, namely the uncertainty of a decision outcome and the reward/punishment, associated to the outcome were manipulated. A behavioral experiment (n =12) and a second one (n =6) using functional magnetic resonance imaging (fMRI) were conducted. Behavioral results of both studies showed the effectiveness of the financial incentive to bias decision making toward a more risky and less rational behavior from a safety point of view. Neuroimaging data showed that the PCE behavior was underpinned by the contribution of brain circuitry of emotion and reward during the decision-making process. Taken together, behavioral and fMRI result support the hypothesis that PCE can be provoked by a temporary impairment of rational decision-making due to the negative emotional consequences attached with the go-around. [Copyright &y& Elsevier]

Abstract: In previous studies, we investigated a group of subjects who had suffered from a severe non missile traumatic brain injury (nmTBI) without macroscopic focal lesions and we found brain atrophy involving the hippocampus, fornix, corpus callosum, optic chiasm, and optic radiations. Memory test scores correlated mainly with fornix volumes . In the present study, we re-examined 11 of these nmTBI subjects approximately 8yr later. High-spatial resolution T1 weighted magnetic resonance images of the brain (1mm3) and standardised memory tests were performed once more in order to compare brain morphology and memory performance originally assessed 3–13 months after head injury (first study) and after 8–10yr (present study). An overall improvement of memory test performance was demonstrated in the latest assessment, indicating that cognitive recovery in severe nmTBI subjects had not been completed within 3–13 months post-injury. It is notable that the volumes of the fornix and the hippocampus were reduced significantly from normal controls, but these volumes do not differ appreciatively between nmTBI subjects at first (after ∼1yr) and at second (after ∼8yr) scans. On the contrary, a clear reduction in the volume of the corpus callosus can be observed after ∼1yr and a further significant reduction is evident after ∼8yr, indicating that the neural degeneration in severe nmTBI continues long after the head trauma and relates to specific structures and not to the overall brain. [Copyright &y& Elsevier]

Abstract: The subventricular zone (SVZ) is a region that lies immediately beneath the ependymal layer on the lateral wall of the lateral ventricles, and is separated from the caudate nucleus by a layer of myelin. It contains multipotent neural stem cells. The aim of this study was to investigate the tissue around the SVZ, with the hypothesis that multimodal MRI is able to highlight the progressive disruption of tissue caused by the neurodegenerative disease in this area. We combined volumetric and diffusion tensor (DTI) imaging using a 3T imager in a cross-sectional study including 30 patients with amnestic-mild cognitive impairment (a-MCI), 30 patients with Alzheimer''s disease (AD) and 30 age- and gender-matched healthy controls (HC). Our data indicate that mean diffusivity (MD) values increase continuously from HC through a-MCI to AD in the bilateral SVZ, where most of the proliferating stem cells in the adult brain are located. This result was specific for the SVZ and could not be observed in other periventricular areas. Multimodal MRI, being able to highlight structural changes of microscopic tissue in humans in vivo, could represent a precious tool to complement histological studies of neurogenesis. [Copyright &y& Elsevier]

Abstract: We used fMRI to investigate the neurofunctional basis of externally and internally timed movements in Parkinson''s disease (PD) patients. Ten PD patients whose medication had been withheld for at least 18h and 11 age- and sex-matched healthy controls were scanned while performing continuation paradigm with a visual metronome. Compared with the controls, PD patients displayed an intact capability to store and reproduce movement frequencies but with a significantly increased movement latencies. No differences in BOLD response were found in both groups when comparing the continuation with the preceding synchronization phase and viceversa, except for activity in visually related regions. Relative to healthy controls during the synchronization phase, PD patients exhibited an overall signal increase in the cerebellum and frontostriatal circuit (putamen, SMA and thalamus) activity together with specific brain areas (right inferior frontal gyrus and insula cortex) that are also implicated in primary timekeeper processes. By contrast, in the continuation phase the only neural network involved to a greater extent by the PD group was the cerebello-thalamic pathway. The lack of neurofunctional differences between the two timing phases suggests that rhythmic externally and internally guided movements engage similar neural networks in PD and matched healthy controls. Moreover, between-group comparison indicates that PD patients OFF medication may compensate for their basal ganglia–cortical loop''s dysfunction using different motor pathways involving cerebellum and basal ganglia relays during the two phases of rhythmic movement. [Copyright &y& Elsevier]

Abstract: A well-known issue in functional neuroimaging studies, regarding motor synchronization, is to design suitable control tasks able to discriminate between the brain structures involved in primary time-keeper functions and those related to other processes such as attentional effort. The aim of this work was to investigate how the predictability of stimulus onsets in the baseline condition modulates the activity in brain structures related to processes involved in time-keeper functions during the performance of a visually cued motor synchronization task (VM). The rational behind this choice derives from the notion that using different stimulus predictability can vary the subject''s attention and the consequently neural activity. For this purpose, baseline levels of BOLD activity were obtained from 12 subjects during a conventional-baseline condition: maintained fixation of the visual rhythmic stimuli presented in the VM task, and a random-baseline condition: maintained fixation of visual stimuli occurring randomly. fMRI analysis demonstrated that while brain areas with a documented role in basic time processing are detected independent of the baseline condition (right cerebellum, bilateral putamen, left thalamus, left superior temporal gyrus, left sensorimotor cortex, left dorsal premotor cortex and supplementary motor area), the ventral premotor cortex, caudate nucleus, insula and inferior frontal gyrus exhibited a baseline-dependent activation. We conclude that maintained fixation of unpredictable visual stimuli can be employed in order to reduce or eliminate neural activity related to attentional components present in the synchronization task. [Copyright &y& Elsevier]