Deep brain stimulation of the ventral intermediate nucleus of the thalamus in medically refractory orthostatic tremor: preliminary observations.

Orthostatic tremor (OT) is a disabling movement disorder associated with postural and gait impairment in the elderly. Medical therapy often yields insufficient benefit. We report the clinical and electrophysiological data on two patients with medication-refractory OT treated with deep brain stimulation of the ventral intermediate thalamic nucleus (Vim DBS). Patient 1 underwent bilateral deep brain stimulation (DBS) and Patient 2 unilateral Vim DBS following 28 and 30 years of disease duration, respectively. Both patients showed increased latency to symptom onset after rising from a seated position, improved tolerance for prolonged standing, and slower crescendo of tremor severity when remaining upright. Postoperative evaluation demonstrated decreased amplitude of electromyographic activity with persistence of well-defined oscillatory behavior showing strong coherence at 15 Hz between all muscles tested in the upper and lower limbs. Postural sway was unchanged. Clinical benefits have been sustained for over 18 months in Patient 1, and receded after 3 months in Patient 2. These findings support the consideration of bilateral Vim DBS implantation as a therapeutic option in patients with medically refractory OT. Further efficacy studies on chronic stimulation to disrupt the abnormal oscillatory activity in this disorder are warranted.

Lower-body parkinsonism: reconsidering the threshold for external lumbar drainage.

BACKGROUND: An 80-year-old man with a 60 pack-year smoking habit, hypertension, and hypercholesterolemia presented to a movement disorders clinic with a 30-month history of step-wise progression of gait, balance, and memory impairment. He had experienced multiple falls and two hospitalizations for sudden-onset freezing of gait. INVESTIGATIONS: Neurological examination, brain MRI, neuropsychological evaluation, gait analysis, continuous external lumbar drainage of cerebrospinal fluid, and post-mortem neuropathological studies. DIAGNOSIS: Vascular parkinsonism was diagnosed on the basis of the patient's history and imaging findings; however, post-mortem neuropathology was consistent with a diagnosis of normal pressure hydrocephalus and did not support that of vascular parkinsonism. TREATMENT: Ventriculoperitoneal shunt placement superseded tighter control of vascular risk factors, as judged by the patient's response to continuous lumbar drainage.