Emotion-specific processing deficit in focal brain-damaged patients.

Focal brain-damaged patients (left hemisphere damage, right hemisphere damage) and hospitalized general medical patients were asked to sort test photographs into target expressions of four facial emotions, happy, sad, fear and anger. In a second task, patients were asked to match neutral photographs with these target emotion expressions in a forced-choice format. Patients were also asked to rate their mood state on a two-dimensional affect grid. Right hemisphere-damaged patients were significantly inaccurate in matching the test-target expressions of facial emotions in comparison to left hemisphere-damaged or general medical patients. Analysis of error scores indicated a bias toward negative emotions by left hemisphere-damaged patients. Congruent to their mood state, left hemisphere-damaged patients also attributed "sadness" on neutral state of expression significantly more often than in right hemisphere-damaged patients.