Recognition of facial expressions: Selective impairment of specific emotions in Huntington's disease

Recognition of facial expressions of basic emotions was investigated in HL and UJ, two people with Huntington's disease who showed little evidence of general cognitive deterioration. No impairments were found in tests of the perception of age, sex, familiar face identity, unfamiliar face identity, and gaze direction, indicating adequate processing of the face as a physical stimulus. Computer-interpolated ("morphed") images of facial expressions of basic emotions were used to demonstrate deficits in the recognition of disgust and fear for UJ. HL also showed a deficit in the recognition of disgust, and was not very adept (but not significantly impaired) at recognising fear. Other basic emotions (happiness, surprise, sadness, anger) were recognised at normal levels of performance by HL and UJ. These results show that impairments of emotion recognition can be circumscribed; affecting some emotions more than others, and occurring in people who do not show pronounced perceptual or intellectual deterioration. Questionnaires examining self-assessed emotion indicated normal experience of anger by HL and UJ, but possible abnormalities for disgust and fear. The processes involved in recognising other people's emotions may therefore be linked to those involved in experiencing emotion, and the basic emotions of fear and disgust may have separable neural substrates.