Dissociable face processing impairments after brain injury.

Matched populations of head-injured patients and normal control subjects completed three "forced-choice" face processing tasks designed to test facial expression recognition, familiar face recognition, and unfamiliar face matching. We hypothesised a significant difference in the performance of the patients and controls on the three tasks, and hoped to observe individual differences in the patients' performance across tasks. As predicted the head-injured patients made significantly more errors than the controls on the forced-choice tasks. Four cases of dissociable impairments affecting only one of the face processing tasks are reported; patient JP impaired only on facial expression recognition, patients AB and HI impaired only on familiar face recognition, and patient VS impaired only on unfamiliar face matching. These dissociable impairments provide further evidence for independent cognitive processing of specific face properties.