MICROGRAPHIA IN PARKINSONS-DISEASE - THE EFFECT OF PROVIDING EXTERNALCUES

Objective-To investigate whether micrographia in patients with Parkins on's disease is lessened either by giving visual targets or by continu ally reminding them that they should write with a normal amplitude. Me thods-Eleven patients with Parkinson's disease (mean age 65.4 years) w ere compared with 14 control subjects (mean age 67.1 years). The subje cts wrote with a stylus on a graphics tablet. There were three conditi ons: free writing, writing with dots to indicate the required size, an d writing with continuous verbal reminders (''big''). Each condition w as performed twice. Results-The patients wrote with a more normal ampl itude when given either the visual cues or the auditory reminders. Thi s improvement persisted when, shortly afterwards, the patients wrote f reely without external cues. The increase in amplitude was achieved ma inly by an increase in movement time rather than in peak velocity. Con clusion-Whereas the visual cues directly specified the required amplit ude the auditory reminders did not. One effect of external cues is tha t they draw attention to the goal, and thus encourage the patients to write less automatically.