Manual performance in leukotomized and unleukotomized individuals with schizophrenia

Seven leukotomized adults with schizophrenia (LS), eight unleukotomized adults with schizophrenia (ULS), and eight healthy control (C) individuals were required to reach toward and grasp a small object that was either stationary or moving. Reflective markers were placed on the subject's index finger, thumb and wrist, and movements were videotaped. As expected the LS and ULS groups moved slower than the C group when the target was stationary. However, when the target was moving, all three groups moved faster, with the LS and C groups having the same movement times, and the ULS group having the fastest movement time. When the timing of the reaching trajectory was assessed, the LS group spent less time decelerating and closing their hands around the object, indicating their movements were controlled with less precision. When grasp formation was analyzed, for the stationary condition, the maximum apertures of the LS and ULS groups were not different, and both were larger than those of the C group. For the moving target condition, aperture increased for all groups but was smallest for the C group, intermediate for the LS group and largest for the S group. There was actually less within subject variability in peak aperture and maximum aperture closing speed for the LS and ULS groups in comparison to the C group, perhaps indicating a limited repertoire of potential motor responses for the patient groups. These results suggest that individuals with schizophrenia are able to use redundant information as well as controls, and that leukotomized individuals with schizophrenia have greater motor control deficits than unleukotomized schizophrenics.