Brain volumetry in Parkinson's disease with and without dementia: where are the differences?

Background: Cognitive dysfunction is well documented in Parkinson's disease (PD). However, association between regional brain volume change and cognitive decline of PD is uncertain.

Purpose: To compare regional brain volume difference between PD without dementia (PDND) and PD with dementia (PDD).

Material And Methods: We enrolled 16 normal controls (mean ± SD: 69.5 ± 6.31) and 32 sex-, age-matched patients with PD (16 PDND and 16 PDD patients with Hoehn & Yahr stage II or III). Cognitive function was assessed using mini-mental status examination (MMSE). Intracranial volume (ICV) and the hippocampal volumes were manually measured using magnetic resonance imaging (MRI). Regional gray/white matter volume changes were analyzed using voxel-based morphometry.

Results: Age, ICV, volume of gray matter volume (GMV), white matter, and hippocampi did not differ among the three groups. The regional GMV of PDD was significantly decreased in the areas of right middle frontal gyrus, short insular gyri, superior temporal gyri; both precuneus compared to PDND (uncorrected P < 0.001). In the partial correlation analysis (controlled for age, sex, ICV), regional GMV of PD was positively correlated with MMSE score in the areas of short insular gyri, right circular insular sulcus, right calcarine sulcus, left superior temporal gyrus (planum porale), and left inferior precentral sulcus (uncorrected P < 0.001).

Conclusion: We suggest that the volume loss of hippocampus may not be a finding in developing of PDD while variation of the regional volume of the frontal, insular cortex, superior temporal gyri, and precuneus lobes may be a phenomenon of PDD.