Brain mechanisms for recognition of faces, facial expression, and gestures: neuropsychological and electroencephalographic studies in normals, brain-lesioned patients, and schizophrenics.

Abstract

The perception and recognition of faces and nonface stimuli were investigated by means of EP techniques in normal subjects. Neuropsychological studies on recognition of faces, facial expression, and gestures were performed in normal subjects, brain-lesioned patients, and schizophrenic patients. 1. Two neuropsychological tests investigating recognition of faces, mimic expression, and gestures were applied in normals and brain-lesioned patients. In the first test, the recognition of faces and vases was tested 1 hr and 1 week after an inspection series. It was found that the size rather than the location of the lesion (excluding occipital lobe lesions) was an important determinant of the error score. No significant differences were found between patients suffering from RH and LH lesions. In general the same observation was true when recognition of faces, expression, and gestures was studied by means of a movie test consisting of 12 10-sec movie scenes and 10 multiple-choice tests following inspection of each scene. A slight tendency to higher error scores appeared in patients suffering from right temporo-occipital lesions compared with other RH lesions. 2. Impairment in the perception and recognition of faces, facial expression, and gestures was also found in schizophrenic patients. Their error score, especially in the movie tests, was on the average higher than in brain-lesioned patients, indicating a major perceptual or cognitive deficit in this disease. This observation is consistent with some clinical symptoms of schizophrenia. It is remarkable that in the slide test, schizophrenic patients had a significantly higher error score in the easy tasks (recognition of upright faces) than normals, whereas in the difficult tasks (involving upside-down faces) their performance was not significantly different from that of an age- and socially matched group. 3. The degree of schizophrenic defect and acute psychotic symptoms had some effect on the impairment in schizophrenics performing these tests. When the error scores of adolescent and middle-aged schizophrenics were compared to corresponding control group error scores, the relative impairment of adolescent schizophrenic patients was found to be somewhat stronger than that of adult schizophrenics. This supports the hypothesis that the impairment in face and mimic recognition found in schizophrenic patients is caused by the disease and not by other factors such as duration of illness or hospitalization. It is conjectured that a component very specific to schizophrenia leads to the dramatic cognitive defect found in our tests in these patients.(ABSTRACT TRUNCATED AT 400 WORDS)