LOSS OF DISGUST - PERCEPTION OF FACES AND EMOTIONS IN HUNTINGTONS-DISEASE

Face perception and emotion recognition were investigated in a group o f people with Huntington's disease and matched controls. In convention al tasks intended to explore the perception of age, sex, unfamiliar fa ce identity (Benton test) and gaze direction from the face, the Huntin gton's disease group showed a borderline impairment of gaze direction perception and were significantly impaired on unfamiliar face matching . With a separate set of tasks using computerinterpolated ('morphed') facial images, people with Huntington's disease were markedly impaired at discriminating anger from fear but experienced less difficulty wit h continua varying from male to female, between familiar identities, a nd from happiness to sadness. In a further test of recognition of faci al expressions of basic emotions from the Ekman and Friesen (1976) ser ies, interpolated images were created for six continua that lay around the perimeter of an emotion hexagon (happiness-surprise, surprise-fea r;fear-sadness; sadness-disgust; disgust-anger; anger-happiness). In d eciding which emotion these morphed images were most like, people with Huntington's disease again showed deficits in the recognition of ange r and fear and an especially severe problem with disgust, which was re cognized only at chance level. A follow-up study with tests of faciall y and vocally expressed emotions confirmed that the recognition of dis gust was markedly poor for the Huntington's disease group, still being no better than chance level. Questionnaires were also used to examine self-assessed emotion, but did not show such striking problems. Taken together these data reveal severe impairments of emotion recognition in Huntington's disease, and show that the recognition of some emotion s is more impaired than others. The possibility that certain basic emo tions may have dedicated neural substrates needs to be seriously consi dered; among these, disgust is a prime candidate.