[Visuo-postural control of schizophrenics--variations of sway area during horizontal eye movement]

In the present study, we investigated the neurological mechanism of commonly known specific or unnatural postures in schizophrenic patients. Using a gravimeter, body sway studied in 26 chronic schizophrenic patients, 10 schizoaffective disorder patients and 21 normal subjects. During eye fixation at a target while keeping an upright posture, schizophrenic patients presented a larger gravimetric area than the normal subjects and the patients with schizoaffective disorder. There was a negative correlation (r = -0.509) between the standard deviation of the sway gravimetric area during fixation and the dose of neuroleptics in schizophrenic patients, but no correlation was found in patients with schizoaffective disorder (r = -0.01), although they took neuroleptics in a similar regimen to that for the schizophrenics. There was no correlation between the standard deviation of the sway gravimetric area during fixation and the duration of illness. There was also no correlation between the former and the amplitude ratio of saccades during smooth pursuit eye movements. When horizontal eye movements pursuing the target were loaded in this experiment, both the normal subjects and the patients with schizoaffective disorder showed a decrease in a loaded gravimetric area and a tendency towards postural stabilization. However, schizophrenic patients having higher SANS scores (Andreasen) presented an increase in gravimetric area. This suggests that schizophrenic patients with higher SANS score may have organic cerebellar changes related to impairment of the mechanism of visual and postural coordinations.