Grey matter abnormalities in methcathinone abusers with a parkinsonian syndrome

Background: A permanent parkinsonian syndrome occurs in intravenous abusers of the designer psychostimulant methcathinone (ephedrone). It is attributed to deposition of contaminant manganese, as reflected by characteristic globus pallidus hyperintensity on T1-weighted MRI. Methods: We have investigated brain structure and function in methcathinone abusers (n=12) compared to matched control subjects (n=12) using T1-weighted structural and resting state functional MRI. Results: Segmentation analysis revealed significant (p<0.05) subcortical grey matter atrophy in methcathinone abusers within putamen and thalamus bilaterally, and the left caudate nucleus. The volume of the caudate nuclei correlated inversely with duration of methcathinone abuse. Voxel-based morphometry showed patients to have significant grey matter loss (p<0.05) bilaterally in the putamina and caudate nucleus. Surface-based analysis demonstrated nine clusters of cerebral cortical thinning in methcathinone abusers, with relative sparing of prefrontal, parieto-occipital and temporal regions. Resting state functional MRI analysis showed increased functional connectivity within the motor network of patients (p