Chronic electrical stimulation of the VL-VPL complex and of the pallidum in the treatment of movement disorders: personal experience since 1982.

Since 1982, we have been able to control involuntary movements associated with deaf-ferentation by means of chronic electrical stimulation of the thalamic sensory nucleus through implanted programmable neuropacemakers. Since 1987, we have been using the same system with electrodes chronically implanted in the VL for treating selected cases of tremor due to Parkinson's disease, multiple sclerosis and in cases of essential tremor. In our series of 60 patients, suppression of tremor was achieved in almost all cases; however, due to dysarthria in 30% of the cases (cases after previous thalamotomy in the other side or with bilateral stimulation), the amplitude of stimulation was corrected and thus some tremor was still observed. The rigidity of parkinsonism was in all cases improved. One case of hemiballism was perfectly controlled with the same technique. Finally, 3 cases of Parkinson's disease with severe hypokinesia, speech and gait disturbances, and on-off phenomenon have been globally improved by a bilateral chronic stimulation of the pallidum.