Prognostic factors of subthalamic stimulation in Parkinson's disease: a comparative study between short- and long-term effects.

BACKGROUND/AIMS: Bilateral subthalamic nucleus deep brain stimulation (STN-DBS) has been shown to have long-term benefits in Parkinson's disease (PD). Through analyzing different variables, this study identified prognostic factors for the short- and long-term effects of STN-DBS.

METHODS: Thirty-six PD patients underwent bilateral STN-DBS. Clinical evaluations were performed 1 month before and 3 months after surgery, with additional follow-up examinations for a mean of 31.3 months.

RESULTS: There was a trend for long-term STN-DBS-induced improvements in the Unified Parkinson's Disease Rating Scale (UPDRS) part II and part III measures to be greater in younger patients. Preoperative levodopa responsiveness only led to consistent UPDRS part III improvement from STN-DBS at 3 months, and this predictive value did not exist in the long term. The preoperative levodopa response of tremor and axial symptoms in motor disability predicted long-term DBS effect only. Preoperative cognitive function positively correlated with postoperative improvement from DBS in UPDRS part III during long-term follow-up only.

CONCLUSIONS: The prognostic factors for STN-DBS benefit were different for short- and long-term follow-ups. Good prognostic factors for long-term STN-DBS for PD patients were good cognitive function and tremor dominance. Poor prognostic factors were related to older age and non-dopaminergic-responsive axial disability.