Deep Brain Stimulation Target Selection in an Advanced Parkinson’s Disease Patient with Significant Tremor and Comorbid Depression

CLINICAL VIGNETTE A 67-year-old female with advanced Parkinson's disease (PD), medically refractory tremor, and a history of significant depression presented for evaluation of deep brain stimulation (DBS) candidacy. CLINICAL DILEMMA Traditionally, the subthalamic nucleus (STN) has been preferred over the globus pallidus interna (GPi) as a DBS target for PD patients with levodopa-responsive fluctuations in rigidity and akinesia, for whom tremor is also a significant source of impairment. However, STN stimulation is avoided in patients with a significant pre-surgical history of mood disorder. CLINICAL SOLUTION Bilateral DBS of the GPi led to significant short-term improvement in PD motor symptoms, including significant tremor reduction. GAP IN KNOWLEDGE There is insufficient evidence to support or refute clinicians' traditional preference for STN stimulation in treating refractory PD tremor. Similarly, the available evidence for risk of worsening depression and/or suicidality after STN DBS is mixed. Both questions require further clarification to guide patient and clinician decision-making.