Use of advance information in patients with schizophrenia

To document possible motor disturbance in schizophrenia, we examined the ab ility to use advance information (or cues) to plan movements in a sequentia l button pressing task in 12 Clozapine medicated patients. Programming of m ovements under various cues revealed that patients with schizophrenia, rela tive to controls, initiated movements slower to the right than left, provid ing possible evidence for right hemineglect (left hemisphere dysfunction). Additionally, patients with schizophrenia had difficulty in the initiation of movements in the absence of a cue, suggesting internal cue generation di fficulty for movement related to some form of fronto-striatal disturbance. Motor abnormalities were predominantly observed at the level of movement in itiation, but not execution, contrary to basal ganglia disorders such as Pa rkinson's and Huntington's disease.