EFFECT OF STIMULATION IN THE VENTRAL INTERMEDIATE NUCLEUS OF THE THALAMUS ON LIMB CENTRAL IN PARKINSONS-DISEASE - A CASE-STUDY

This study focuses on upper extremity strength and movement control in a patient with Parkinson's disease who had stimulating electrodes sur gically implanted in the ventral intermediate nucleus (VIM) of the lef t thalamus. We examined torque generation and control of movement dist ance in single degree-of-freedom elbow movements under three different stimulation conditions: (a) no stimulation, (b) high stimulation, in which tremor was minimized but there was also tingling and perceived w eakness, and (c) moderate stimulation, in which tremor was partially r educed, but there was also a subjective sense of increased strength co mpared with the high-stimulation condition. The patient's ability to g enerate both steady torque and rapid movements was poorest with no sti mulation. The patient generated the largest torques with moderate stim ulation and performed the fastest movements with high stimulation. How ever, even with tremor minimized, the patient's electromyogram (EMG) b urst patterns were not typical of those of neurologically healthy subj ects, although the movements were clearly improved.