The thalamus was the first site that was studied, and in 1997, the FDA approved deep brain stimulation of the thalamus for the treatment of unilateral Parkinson tremor. Parkinson tremor is dramatically reduced with DBS of the thalamus. In as many as 50 percent of patients, the tremor is totally abolished. However, other parkinsonian symptoms, such as stiffness, slowness, and difficulty with ambulation, are not improved with stimulation of the thalamus. In reported cases of DBS of the thalamus, there were no serious side effects and no deaths with the procedure.
Many patients experience a tingliness of the hand when the battery was turned down.
The patients hold a handheld magnet with which they can turn the stimulator on and off. Patients are instructed to turn their stimulators off at night. Because only tremor was affected by deep brain stimulation of the thalamus, there was a search for other brain site targets. Deep brain stimulation of the globus pallidus, which was studied first, was shown to have effectiveness in reducing Parkinson tremor. In fact, the results were very similar to a widespread procedure called pallidotomy, in which an ablative or destructive lesion is placed in the GPi.