The impact of thalamic stimulation on activities of daily living for essential tremor

BACKGROUND Deep Brain Stimulation (DBS) of the ventro-intermedius nucleus of the thalamus is the treatment of choice for drug-refractory essential tremor (ET). This study evaluated the effectiveness of thalamic stimulation in improving the patient's quality of life through activities of daily living. METHODS Sixteen ET patients completed a health questionnaire, the "Tremor Activities of Daily Living Scale" (TADLS) measured by the patient, a 10-item subset of the TADLS measured by the clinician, and the Fahn-Tolosa-Marin tremor rating scale (TRS). Each patient was evaluated with the stimulator on and off with the average evaluation occurring 13 months after surgery. Additionally, improvements on the TADLS were compared to electrode positioning on the axial plane and stimulation parameters. RESULTS There was a 44.0% improvement in the patient-rated TADLS, a 45.2% improvement in the clinician-rated TADLS, and a 33.9% improvement in the TRS. The average electrode location was 5.65 mm anterior to the posterior commissure (AC-PC), 13.4 mm lateral from the midline, and 2.0 mm below the AC-PC line. The average stimulation parameters were 2.74 Volts, 160 Hertz, and 119 musec. There was no correlation. between improvements on the TADLS, electrode location, and stimulation parameters. Of the 16 patients, 10 patients would repeat the surgery, two were unsure, and four would not repeat the surgery. CONCLUSIONS. Tremor is significantly controlled with DBS and activities of daily living are highly correlated with patient satisfaction. The degree of improvement in the four patients who would not repeat the surgery was outweighed by the negative factors associated with the surgery. (C) 2003 Elsevier Inc. All rights reserved.