The perception of emotional chimeric faces in schizophrenia: further evidence of right hemisphere dysfunction.

OBJECTIVE

To examine lateral perceptual bias, an index of right hemisphere function, and its relation to performance on a standard facial perception test and to clinical variables in a large sample of first episode and chronic schizophrenia.

BACKGROUND

Judgments made on chimeric faces reliably elicit a perceptual bias to the left hemispace, presumed to be a result of right hemisphere dominance for spatial attention. Recent studies have suggested that this bias is reduced or absent in people with schizophrenia.

METHODS

Fifty first-episode and 50 patients with chronic schizophrenic and 50 control subjects were given a brief neuropsychologic battery that included a Happy-Sad Chimeric Face test and the Benton Facial Recognition Test. All patients were rated on the Positive and Negative Syndrome Scale of Schizophrenia after 4 weeks of neuroleptic treatment. All were right handed

RESULTS

The patients with schizophrenia showed a significantly weaker perceptual left hemispatial bias compared with controls. In fact the mean bias was in the opposite direction in the chronic group. There was no correlation between left hemispatial bias and either positive or negative symptoms, current medication dose, or mood. Results from the Benton test revealed a performance deficit among the patients with schizophrenia compared with controls but was not correlated with performance on the chimeric faces test in the patients.

CONCLUSIONS

The results confirm a specific deficit in right hemisphere attentional functions in schizophrenia, which is separate from a general impairment in facial processing. The deficit is most marked in chronic patients but further study is required to determine whether this is a consequence of prolonged illness.