White matter hyperintensities and cortical acetylcholinesterase activity in parkinsonian dementia

To investigate the relationship between the severity of white matter hyperintensities (WMH) and cortical acetylcholinesterase (AChE) activity in parkinsonian dementia (PDem). PDem (n = 11) and control subjects (n = 14) underwent [C-11]methyl-4-piperidinyl propionate (C-11-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)]. Analysis demonstrated significantly lower mean cortical C-11-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). The concomitant presence of mild to moderate WMH in patients with PDem does not have a significant effect on cortical AChE activity.