A quantitative measure of postural sway deficits in schizophrenia

Clinicians rely on observational methods to assess obvious signs of postural abnormalities in schizophrenia, yet subtle signs of postural deficits may go unnoticed. Posture is controlled, in large part, by the cerebellum, which has been implicated in numerous reports of structural and functional deficits in schizophrenia. Given the possibility of an underlying disruption of cerebellar function in schizophrenia, this study used an objective, quantitative measure to assess the magnitude of postural stability in this disorder. A total of 36 schizophrenia patients and 36 non-psychiatric age-matched controls stood on a pressure-sensitive platform that recorded shifts in weight (body sway) through pressure points in the feet. Patients demonstrated more postural sway than did healthy controls (p<0.01). When patients with noticeable signs of tardive dyskinesia were removed from analyses, group differences remained (p<0.01). There was no significant correlation between neuroleptic medication level and degree of postural sway (r=0.16, p=0.37). These results indicate that patients with schizophrenia have subtle, yet quantifiable, disturbances in the control of posture and balance. Quantitative measures of postural sway may provide a more sensitive means of detecting disturbances of movement than do standard clinical observations alone.