Comprehension of Emotion in Neurodegenerative Disorders A Thesis

Comprehension of Emotion in Neurodegenerative Disorders Kelly L. Davis Prof. Douglas L. Chute While the dysprosody associated with Parkinson’s disease (PD) has been well described, findings from investigations on the comprehension of emotional intonation have been mixed. A hypothetical model of the requisite skills for comprehension of affective prosody is described and argues for the role of perceptual skills, executive functioning, and affective competence in the interpretation of emotional intonation. To evaluate this model, the comprehension of emotional and non-emotional prosody was examined among individuals with PD (n=11), neurologically healthy age and education-matched elders (EC, n=16), and college-age adults (YC, n=16). Stimuli included auditory recordings of professional actors rendering utterances of minimal semantic content (i.e., dates, numbers) using emotional (tentative to dominant) and nonemotional attitudes (speaker close to intended listener, at a conversational distance, and far apart). Participants were instructed to rate 90 auditory stimuli of emotional attitudes and an additional 90 non-emotional stimuli using 5-point Likert-type scales. Between group comparisons showed that the PD and EC subjects do not differ in their judgments of affective or non-affective prosody stimuli, yet the performance of the PD group was different from the YC group on both affective and non-affective tasks. Within-group comparisons revealed an age-related effect on performance for affective prosody judgments. The YC xi group did not differ in judgments of emotional and non-emotional prosody. There was no difference between groups in judgments of fundamental perceptual elements of prosody (pitch, duration, volume). A statistically significant correlation between emotional prosody comprehension and working memory was observed for all participants. Similarly, a significant correlation was revealed for the emotional prosody comprehension and performance on emotional facial recognition tasks. Findings support the hypothetical model that argues that working memory capacity is related to the comprehension of emotional cues expressed by others. Contrary to expectations, the PD and EC groups interpreted emotional cues differently than younger adults. These results suggest that other populations with decreased working memory capacity may interpret emotional cues from others differently than healthy younger adults. Furthermore, recommendations for future research include careful evaluation of task demands and aspects of executive control between affective and nonaffective comprehension tasks. [Multi-media CD-ROM accompanies the manuscript.]