There have been many reports on the effects of ablation of subcortical areas on Parkinson tremor but little on the effects of stimulation alone. The present investigation was an attempt to observe the tremor of parkinsonism during stimulation in the diencephalon. To more adequately evaluate the effects of diencephalic stimulation, patients who had unilateral clinical tremor were selected for extensive tremor recordings during stereotaxic surgery. The tremograms were scanned for frequency characteristics, amplitude, wave form, and laterality of the tremor. Particular attention was given to effects on the side presenting no clinical evidence of tremor.
Subjects.—This study was done on a group of 24 patients chosen because of displaying unilateral clinical tremor. However, all of the patients showed some degree of generalized Parkinson involvement such as diminished arm flinging, gait changes, slowness in generalized and specific movements, decrement in rapid opening and closing of the eyes and