Dynamic emotion processing in Parkinson's disease as a function of channel availability

Abstract

Parkinson's disease (PD) is linked to impairments for recognizing emotional expressions, although the extent and nature of these communication deficits are uncertain. Here, we compared how adults with and without PD recognize dynamic expressions of emotion in three channels, involving lexical–semantic, prosody, and/or facial cues (each channel was investigated individually and in combination). Results indicated that while emotion recognition increased with channel availability in the PD group, patients performed significantly worse than healthy participants in all conditions. Difficulties processing dynamic emotional stimuli in PD could be linked to striatal dysfunction, which reduces efficient binding of sequential information in the disease.

Keywords:

• Visual
• Auditory
• Emotion
• Parkinson's disease
• Basal ganglia
• Audiovisual speech

The authors wish to thank Alla Sorokin for help with data acquisition, Stephen Hopkins for help with stimulus preparation, and Catherine Knowles for help with preparing figures and tables. This research was financed by a grant from the Canadian Institutes of Health Research, Institute of Aging (to M.D.P.). The support of the German Academic Exchange Service (DAAD) to the first author and the Fonds de la Recherche en Santé du Québec to the second author is gratefully acknowledged.

Notes

¹As our validation study showed no difference in the recognition of emotions from silent, unimodal face stimuli when actors were producing lexical versus pseudosentences, lexical sentences are presented here whenever possible because they are more ecologically valid.

²The modified alpha value is obtained by the following formula: alpha multiplied by the degrees of freedom associated with the conditions tested, divided by the number of comparisons (Keppel, 1991). For significant effects involving the emotion factor, with alpha set at .05, there were 15 contrasts with a corrected p = .017. Elaboration of significant effects involving the channel variable included 6 contrasts resulting in a corrected p = .05.

³To confirm the advantage of multimodal stimuli over uni- and bimodal stimuli, we carried out a second ANOVA with condition (uni, bi, or multimodal stimuli) as a repeated measurement factor. This analysis yielded a significant condition main effect, F(2, 40) = 42.81, p < .0001. Planned comparisons confirmed that recognition of both bimodal, F(1, 20) = 22.78, p < .0001, and multimodal, F(1, 20) = 83.53, p < .0001, stimuli exceeded unimodal stimuli and also that multimodal stimuli were recognized significantly better than bimodal stimuli, F(1, 20) = 20.69, p < .001.

⁴In fact, one may argue that the input system would be activated more strongly when bimodal or multimodal stimuli are encountered than when the stimuli are unimodal, explaining the advantage for multimodal emotion recognition (cf., e.g., Paulmann et al., 2009a).