A Study of Emotional Processing in Parkinson's Disease

Abstract

This study investigated three aspects of processing materials with emotional content in patients with idiopathic Parkinson's disease (PD): the ability to produce affective prosody, to discriminate affectively loaded speech, and to detect the surprise element in humorous sketches. Study aims were the characterization of an emotional processing deficit, and to test whether impaired emotional processing is mental state dependent. Forty-eight nondemented PD patients were divided according to neuropsychological criteria into a sample with intact mental functions and a sample with mild to moderate cognitive deterioration, particularly memory impairment. PD patients with intact cognitive functions were solely impaired at producing affectively loaded sentences, but otherwise displayed normal emotional processing abilities as compared to a clinical control group. PD patients with mental impairment were significantly disabled on all three tasks. The observed emo- tional processing deficit was not related to variables like age, disease duration, de- gree of functional impairment, motor disability or depression. Active and receptive emotional prosody were significantly correlated. Further strong positive correlations were found between the ability to disclose pictorial humour and tasks of visuo-conceptual knowledge, as well as between the ability to produce affectively loaded speech and years of schooling. These results were interpreted as indicating that not only the production of emotional prosody, but also its recognition and the discovery of pictorial humour are reduced in a subgroup of PD patients with mental impairment. Impaired emotional processing skills are mental state dependent findings in PD which seem to be independent from demographic or disease variables and may indicate beginning dementia.