Higher brain function disturbance in Parkinson's disease patients: an evaluation based on electrophysiological investigation

Abstract

Background: Higher brain function disturbance such as the central executive of working memory impairment is thought to exist even in early-stage nondemented idiopathic Parkinson's disease patients (PDPs). Methods: Resting EEG, simple oddball paradigm and novel task event-related potentials (ERPs) topography were measured in early-stage nondemented PDPs (MMSE>26), and age-matched normal controls (NCs). The new modified Wisconsin Card Sorting Test (WSCT) was used to evaluate the frontal lobe function. Results and interpretation: There were no natural novelty P3s to be found in PDPs. P3b latency did not differ between PDPs and controls. In addition, increased P3b amplitude for the target stimulus was found in nondemented PDPs. Moreover, the nondemented PDPs showed increased amplitude of resting EEG. PDPs showed significant decreasing of the achieved categories and increasing of perseverative errors in WSCT. Conclusions: The results of the present study suggest that higher brain function disturbance such as the central executive of working memory impairment in nondemented PDPs may be based on the disturbance of mental set change, parallel processing and inhibition of the cortical function due to dysfunction of basal ganglia.