Tractography-guided versus clinical contact selection for deep brain stimulation in tremor - A prospective clinical trial

BACKGROUND: Imaging-guided programming strategies for deep brain stimulation (DBS) offer the potential to reduce programming time and complexity. However, evidence-based paradigms tailored to tremor remain unavailable. Converging research points to an involvement of the dentato-rubro-thalamic tract (DRTT) in tremor pathophysiology across diseases, providing a potential target for imaging-guided programming in Essential Tremor (ET) and Parkinson's Disease (PD). OBJECTIVE: To prospectively evaluate whether imaging-guided contact selection for tremor control based on individual tractography of the DRTT is non-inferior to clinical contact selection. METHODS: Tremor control was assessed in an acute challenge for each DBS contact in 16 ET and 24 PD patients with directional DBS leads in the thalamic ventral intermediate nucleus/posterior subthalamic area (ET) or subthalamic nucleus (PD). The effect of the clinically most effective contact was compared to the effect of the contact with the largest overlap of the stimulation spread with the individual DRTT. Primary outcome was the difference in relative tremor improvement between clinical and imaging-guided contact selection, assessed by an accelerometry-based tremor score, assuming a non-inferiority margin of ≤20%. RESULTS: Tremor control achieved via the imaging-based selected contact was non-inferior to tremor control via the contact chosen by clinical testing for ET (median difference best clinical vs. best imaging-based contact -8%, 95% CI -11.5% to -3.5%) and PD (median difference -10%, 95% CI -20% to -4%). CONCLUSION: This study provides class-II evidence that the overlap of the stimulation spread with the individual DRTT is a suitable marker for imaging-guided contact selection for DBS in tremor.