Objectives: Determine the long-term efficacy of thalamic deep brain stimulation (DBS) for treatment of tremor among individuals with tremor-predominant Parkinson's disease (PD).Design. Longitudinal, unblinded assessment of tremor and activities of daily living (ADL) at baseline (pre-surgical), and post-operative intervals of 1, 3, and 12 months, and annually thereafter up to 3 years.
Methods: A clinical series of 19 individuals undergoing placement of a DBS system for treatment of PD-related tremor. A battery of subjective and objective measures of tremor was completed at planned pre- and post-operative intervals.
Results: Stimulation was associated with significant improvement on subjective and objective measures of ADL performance, midline tremor, and contralateral upper and lower extremity tremor, including parkinsonian resting and action tremors, over the follow-up period. Ipsilateral tremor showed little or no effect of stimulation after the first 3 months. Antiparkinsonian medication use and stimulation parameters showed little or no change over the course of follow-up. About half (53%) of all individuals reported at least one side effect, generally mild, during the follow-up period, with paresthesias and dysarthria being the most common. A total of two leads required replacement due to (1) infection, and (2) adverse side effects (i.e. burning and tingling with stimulation).
Conclusion: DBS is associated with stable tremor control in PD. Side-effects are typically easily managed with stimulation adjustments, although in some cases lead replacement may be required.