ALTERED FORCE RELEASE CONTROL IN PARKINSONS-DISEASE

Isometric force tracking and force aiming modified by visual feed-back was investigated in Parkinsonian (PD) and control subjects. Productio n and maintenance of isometric force, production and release of isoton ic force, and maximum force were tested. Statistical analysis revealed that the PD patients could perform most force tasks in a similar mann er to that of control subjects. However, PD patients had difficulties in sustaining target force over a 30-s period and in performing rapid alternating movements. The major finding in PD patients was an inabili ty to precisely release a target force. Overall these data suggest tha t the release of a produced force is a sensitive motor control paramet er in Parkinson's disease.