ORCID Profile
0000-0002-2339-8168
Current Organisation
KU Leuven
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Publisher: Cambridge University Press (CUP)
Date: 18-07-2014
DOI: 10.1017/S0033291713001712
Abstract: Hippoc al pathology has been proposed to underlie clinical, functional and cognitive impairments in schizophrenia. The hippoc us is a highly plastic brain region examining change in volume, or change bilaterally, over time, can advance understanding of the substrate of recovery in psychosis. Magnetic resonance imaging and outcome data were collected at baseline and 6-year follow-up in 42 first-episode psychosis subjects and 32 matched controls, to investigate whether poorer outcomes are associated with loss of global matter and hippoc al volumes. Bilateral hippoc al increase (BHI) over time, as a marker of hippoc al plasticity was hypothesized to be associated with better outcomes. Regression analyses were performed on: (i) clinical and functional outcomes with grey matter volume change and BHI as predictor variables and (ii) cognitive outcome with BHI as predictor. BHI was present in 29% of psychosis participants. There was no significant grey matter loss over time in either patient or control groups. Less severe illness course and lesser symptom severity were associated with BHI, but not with grey matter change. Employment and global function were associated with BHI and with less grey matter loss. Superior delayed verbal recall was also associated with BHI. BHI occurs in a minority of patients following their first psychotic episode and is associated with good outcome across clinical, functional and cognitive domains.
Publisher: Mary Ann Liebert Inc
Date: 03-2017
Abstract: Traumatic brain injury (TBI) often leads to impairments in gait performance. However, the underlying neurostructural pathology of these gait deficits is poorly understood. We aimed to investigate regional gray matter (GM) volume in young moderate-to-severe TBI participants (n = 19 age 13 years 11 months ±3 years 1 month), compared with typically developing (TD) participants (n = 30 14 years 10 months ±2 years 2 months), and assess whether reduced volume was related to impaired gait performance in TBI participants. Cortical and subcortical GM structures involved in the neural control of gait were selected as regions of interest (ROIs) and their volume was extracted using Freesurfer. Moreover, established spatiotemporal markers of gait impairments in TBI participants, including step length asymmetry, step length variability, and double support time, were obtained using an electronic walkway. Compared with TD participants, TBI participants showed increased double support time, step length asymmetry, and step length variability, suggesting a reduced gait control. Secondly, in TBI participants, reduced volumes were demonstrated in overall subcortical GM and in idual subcortical ROIs, including the hippoc us, cerebellar cortex, putamen, and thalamus. Moreover, in the TBI group, volume losses in subcortical ROIs were highly inter-correlated, indicating that atrophy tends to occur in combined subcortical structures. Finally, it was demonstrated, for the first time, that gait abnormalities in TBI subjects were associated with reduced volume in specific GM structures, including the hippoc us, thalamus, and the cerebellar, superior frontal, paracentral, posterior cingulate, and superior parietal cortices. The present study is an important first step in the understanding of the neurostructural pathology underlying impaired gait in TBI patients.
Publisher: Springer Science and Business Media LLC
Date: 02-03-2021
DOI: 10.1038/S41531-021-00163-0
Abstract: The onset of freezing of gait (FOG) in Parkinson’s disease (PD) is a critical milestone, marked by a higher risk of falls and reduced quality of life. FOG is associated with alterations in subcortical neural circuits, yet no study has assessed whether subcortical morphology can predict the onset of clinical FOG. In this prospective multimodal neuroimaging cohort study, we performed vertex-based analysis of grey matter morphology in fifty-seven in iduals with PD at study entry and two years later. We also explored the behavioral correlates and resting-state functional connectivity related to these local volume differences. At study entry, we found that freezers ( N = 12) and persons who developed FOG during the course of the study (converters) ( N = 9) showed local inflations in bilateral thalamus in contrast to persons who did not (non-converters) ( N = 36). Longitudinally, converters ( N = 7) also showed local inflation in the left thalamus, as compared to non-converters ( N = 36). A model including sex, daily levodopa equivalent dose, and local thalamic inflation predicted conversion with good accuracy (AUC: 0.87, sensitivity: 88.9%, specificity: 77.8%). Exploratory analyses showed that local thalamic inflations were associated with larger medial thalamic sub-nuclei volumes and better cognitive performance. Resting-state analyses further revealed that converters had stronger thalamo-cortical coupling with limbic and cognitive regions pre-conversion, with a marked reduction in coupling over the two years. Finally, validation using the PPMI cohort suggested FOG-specific non-linear evolution of thalamic local volume. These findings provide markers of, and deeper insights into conversion to FOG, which may foster earlier intervention and better mobility for persons with PD.
No related grants have been discovered for Sima Chalavi.