Production of spontaneous and posed facial expressions in patients with Huntington's disease: Impaired communication of disgust

Several studies have reported impairment in the recognition of facial expressions of disgust in patients with Huntington's disease (HD) and preclinical carriers of the HD gene. The aim of this study was to establish whether impairment for disgust in HD patients extended to include the ability to express the emotion on their own faces. Eleven patients with HD, and 11 age and education matched healthy controls participated in three tasks concerned with the expression of emotions. One task assessed the spontaneous production of disgust-like facial expressions during the smelling of offensive odorants. A second assessed the production of posed facial expressions during deliberate attempts to communicate emotion. The third task evaluated HD patients' ability to imitate the specific facial configurations associated with each emotion. Foul odours induced fewer disgust-like facial reactions in HD patients than in controls, and patients' posed facial expressions of disgust were less accurate than the posed disgust expressions of controls. The effect was selective to disgust; patients had no difficulty posing expressions of other emotions. These impairments were not explained by compromised muscle control: HD patients had no difficulty imitating the facial movements required to display disgust. Viewed together with evidence of difficulty in other aspects of disgust in HD, the findings suggest that a common substrate might participate in both the processing and the expression of this emotion.