MANUAL PERFORMANCE IN LEUKOTOMIZED AND UNLEUKOTOMIZED INDIVIDUALS WITH SCHIZOPHRENIA

Seven leukotomized adults with schizophrenia (LS), eight unleukotomize d adults with schizophrenia (ULS), and eight healthy control (C) indiv iduals were required to reach toward and grasp a small object that was either stationary or moving. Reflective markers were placed on the su bject's index finger, thumb and wrist, and movements were videotaped. As expected the LS and ULS groups moved slower than the C group when t he target was stationary. However, when the target was moving, all thr ee groups moved faster, with the LS and C groups having the same movem ent times, and the ULS group having the fastest movement time. When th e timing of the reaching trajectory was assessed, the LS group spent l ess time decelerating and closing their hands around the object, indic ating their movements were controlled with less precision. When grasp formation was analyzed, for the stationary condition, the maximum aper tures of the LS and ULS groups were not different, and both were large r than those of the C group. For the moving target condition, aperture increased for all groups but was smallest for the C group, intermedia te for the LS group and largest for the S group. There was actually le ss within subject variability in peak aperture and maximum aperture cl osing speed for the LS and ULS groups in comparison to the C group, pe rhaps indicating a limited repertoire of potential motor responses for the patient groups. These results suggest that individuals with schiz ophrenia are able to use redundant information as well as controls, an d that leukotomized individuals with schizophrenia have greater motor control deficits than unleukotomized schizophrenics.