Longitudinal evaluation of cerebral morphological changes in Parkinson's disease with and without dementia

To investigate the pattern of brain atrophy across time in a sample of Parkinson's disease (PD) patients with and without dementia using voxelbased morphometry (VBM) analysis. The initial sample comprised thirteen non-demented PD patients and sixteen demented patients. Longitudinal cognitive assessment and structural MRI were performed. The mean follow-up period was 25 months (SD=5.2). From this initial group, eight PD patients with dementia (5 men and 3 women) and eleven PD patients without dementia (7 men and 4 women) were reevaluated. MRI 3D structural images were acquired and analyzed by means of the optimized VBM procedure with Statistical Parametric Mapping (SPM2). VBM analysis showed a progressive grey matter volume decrease in patients with PD without dementia in limbic, paralimbic and neocortical associative temporooccipital regions. In patients with dementia the loss mainly involved neocortical regions. VBM revealed a significant loss of grey matter volume in PD patients with and without dementia with disease progression. The decrease in limbic and paralimbic regions is widespread in non-demented patients. Neocortical volume reduction is the most relevant finding in patients with dementia. This suggests that the neocortex is a substrate for dementia in Parkinson disease.