Optimally, the surgical protocol includes stereotaxic ventriculography to identify targets followed by electrical activity recordings of the structures crossed by the electrode. Finally, a minute study of the stimulation effects is performed under sterotaxic control while the patient is awake. Indications for thalamic stimulation in Parkinson's disease have given way to subthalamic stimulation which improves tremor, bradykinesia and rigidity simultaneously. This result confirms the implication of the subthalamic nucleus in the pathogenesis of Parkinson syndromes. The palladium may be stimulated in Parkinson's patients with major iatrogenic involuntary movements.
Thalamic stimulation is indicated for essential tremor.
The efficacy of chronic stimulation is currently under evaluation in other indications. Neuropsychological functioning in a patient with essential tremor with and without bilateral VIM stimulation. Electrodes were implanted bilaterally in the ventral intermediate nucleus of the thalamus during a single operation. Upon evaluation at 3 months postsurgery, bilateral stimulation was associated with a clinically significant reduction in tremor ratings and improvement in manual dexterity. At that time, a battery of neuropsychological measures was administered with and without bilateral stimulation.