White matter hyperintensities and cortical acetylcholinesterase activity in parkinsonian dementia.

Objective: To investigate the relationship between the severity of white matter hyperintensities (WMH) and cortical acetylcholinesterase (AChE) activity in parkinsonian dementia (PDem).

Methods: PDem (n = 11) and control subjects (n = 14) underwent [11C]methyl-4-piperidinyl propionate (11C-PMP) AChE brain positron emission tomography and magnetic resonance (MR) imaging. Presence of WMH on proton density and T2 MR images was scored using a modified version of the semi-quantitative rating scale by Scheltens et al. [J Neurol Sci114 (1993)].

Results: Analysis demonstrated significantly lower mean cortical (11)C-PMP k3 hydrolysis rates in PDem (-19.9%) when compared with control subjects (P < 0.0001). PDem subjects had higher mean severity of WMH (+20.1%) when compared with control subjects (P < 0.05). When WMH severity was entered into the analysis of variance model, there was no significant co-variate effect on cortical AChE activity (F = 0.24, ns).

Conclusions: The concomitant presence of mild to moderate WMH in patients with PDem does not have a significant effect on cortical AChE activity.