Altered subjective fear response in Huntington's disease

Patients with Huntington's disease (HD) have been shown to exhibit impairment in the recognition of facial expressions such as disgust, as well as deficits in disgust responses to olfactory and gustatory stimuli. The present study investigated whether HD is associated with changes in emotional responses to a variety of visual and verbal stimuli selected to elicit core disgust, moral disgust, fear and happiness. Thirteen patients with HD and twelve controls provided emotional ratings after both reading emotion eliciting scenarios and viewing pictures from the International Affective Picture System database. Patients with HD exhibited executive dysfunction. In comparison to controls, they gave similar ratings for happy stimuli and did not differ significantly in response to core disgust or moral disgust stimuli. However, they did exhibit lower fear ratings in response to both sets of fear stimuli (pictures and scenarios), and higher anger ratings than controls in response to fear pictures. These differences in fear response could reflect dysfunction within frontostriatal pathways involving the amygdala. Changes to fear responses in HD may impair decision making and lead to increased risk-taking behaviour with significant personal or social consequences.