Browsing by Author "Fouche J.-P."
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- ItemA diffusion tensor imaging and neurocognitive study of HIV-positive children who are HAART-naïve "slow progressors"(2012) Hoare J.; Fouche J.-P.; Spottiswoode B.; Donald K.; Philipps N.; Bezuidenhout H.; Mulligan C.; Webster V.; Oduro C.; Schrieff L.; Paul R.; Zar H.; Thomas K.; Stein D.There are few neuropsychological or neuroimaging studies of HIV-positive children with "slow progression". "Slow progressors" are typically defined as children or adolescents who were vertically infected with HIV, but who received no or minimal antiretroviral therapy. We compared 12 asymptomatic HIV-positive children (8 to 12 years) with matched controls on a neuropsychological battery as well as diffusion tensor imaging in a masked region of interest analysis focusing on the corpus callosum, internal capsule and superior longitudinal fasciculus. The "slow progressor" group performed significantly worse than controls on the Wechsler Abbreviated Scale of Intelligence Verbal and Performance IQ scales, and on standardised tests of visuospatial processing, visual memory and executive functioning. "Slow progressors" had lower fractional anisotropy (FA), higher mean diffusivity (MD) and radial diffusivity (RD) in the corpus callosum (p0<0.05), and increased MD in the superior longitudinal fasciculus, compared to controls. A correlation was found between poor performance on a test of executive function and a test of attention with corpus callosum FA, and a test of executive function with lowered FA in the superior longitudinal fasiculus. These data suggest that demyelination as reflected by the increase in RD may be a prominent disease process in paediatric HIV infection. © Journal of NeuroVirology, Inc. 2012.
- ItemDiffusion tensor imaging in anxiety disorders(2012) Ayling E.; Aghajani M.; Fouche J.-P.; Van Der Wee N.Diffusion tensor imaging (DTI) can be used to examine the structural integrity of regional white matter and to map white matter tracts. DTI studies have been performed in several psychiatric disorders, especially in those for which a developmental or a neuropsychiatric component was postulated. Thus far, the use of DTI has been very limited in panic disorder, social anxiety disorder, and generalized anxiety disorder, and somewhat more extensive in post-traumatic stress disorder and obsessive-compulsive disorder. In most anxiety disorders, the results of DTI studies are in line with other structural and functional MRI findings and can be interpreted within the frameworks of existing models for the neurocircuitry of the various disorders. DTI findings could further enrich neurobiological models for anxiety disorders, although replication is often warranted, and studies in pediatric populations are lagging behind remarkably. © Springer Science+Business Media, LLC 2012.
- ItemEvidence for fractional anisotropy and mean diffusivity white matter abnormalities in the internal capsule and cingulum in patients with obsessive-compulsive disorder(2012) Lochner C.; Fouche J.-P.; du Plessis S.; Spottiswoode B.; Seedat S.; Fineberg N.; Chamberlain S.R.; Stein D.J.Background: There is evidence to suggest that obsessive-compulsive disorder (OCD) is associated with structural abnormalities in cortico-striato-thalamic circuits, yet the extent of white matter abnormalities is not well established. In this study, we used diffusion tensor imaging (DTI) to examine white matter integrity in specific regions of interest (ROIs) in patients with OCD. Methods: Patients with OCD and sex-, age- and IQ-matched healthy controls underwent DTI. The primary objective was to explore whether patients with OCD had white matter abnormalities in the anterior limb of the internal capsule (ALIC), the uncinate fasciculus, the genu of the corpus callo-sum and the cingulum. The secondary objective was to evaluate the relation between fractional anisotropy and mean diffusivity in these ROIs and other clinical variables (including age at onset of OCD, OCD severity and levels of depressive and anxiety symptomatology) in patients with OCD. Results: There were 15 patients and 17 controls enrolled in our study. Compared with healthy controls, patients with OCD showed increased fractional anisotropy in bilateral regions of the ALIC adjacent to the body of the caudate, as well as decreased fractional anisotropy in the right anterior limb near the head of the caudate. Patients also had decreased mean diffusivity in the body of the right cingulum and the left anterior cingulum compared with controls. Correlational analyses revealed significant associations of fractional anisotropy and mean diffusivity in select circuits with OCD, depression and anxiety severity scores. Limitations: Inclusion of patients with OCD receiving pharmacotherapy may have been a limitation. In addition, the patients were heterogeneous in terms of their obsessive-compulsive symptom profiles; we did not distinguish between different obsessive-compulsive symptom dimensions. Conclusion: The study results provide further evidence for OCD-related white matter abnormalities in the ALIC and cingulum, consistent with a cortico striatal model of OCD. © 2012 Canadian Medical Association.
- ItemGrey matter abnormalities in social anxiety disorder: A pilot study(2012) Syal S.; Hattingh C.J.; Fouche J.-P.; Spottiswoode B.; Carey P.D.; Lochner C.; Stein D.J.While a number of studies have explored the functional neuroanatomy of social anxiety disorder (SAD), data on grey matter integrity are lacking. We conducted structural MRI scans to examine the cortical thickness of grey matter in individuals with SAD. 13 unmedicated adult patients with a primary diagnosis of generalized social anxiety disorder and 13 demographically (age, gender and education) matched healthy controls underwent 3T structural magnetic resonance imaging. Cortical thickness and subcortical volumes were estimated using an automated algorithm (Freesurfer Version 4.5). Compared to controls, social anxiety disorder patients showed significant bilateral cortical thinning in the fusiform and post central regions. Additionally, right hemisphere specific thinning was found in the frontal, temporal, parietal and insular cortices of individuals with social anxiety disorder. Although uncorrected cortical grey matter volumes were significantly lower in individuals with SAD, we did not detect volumetric differences in corrected amygdala, hippocampal or cortical grey matter volumes across study groups. Structural differences in grey matter thickness between SAD patients and controls highlight the diffuse neuroanatomical networks involved in both social anxiety and social behavior. Additional work is needed to investigate the causal mechanisms involved in such structural abnormalities in SAD. © Springer Science+Business Media, LLC 2012.
- ItemWhite-matter damage in clade C HIV-positive subjects: A diffusion tensor imaging study(2011) Hoare J.; Fouche J.-P.; Spottiswoode B.; Sorsdahl K.; Combrinck M.; Stein D.J.; Paul R.H.; Joska J.A.