Directional Deep Brain Stimulation Programming: Is the Segment Clearly Identifiable and Stable Over Time?

Abstract

AbstractBackgroundIn our early experience programming directional deep brain stimulation (d‐DBS) in PD, we found the optimal directional segment changed over time in some patients. To determine the frequency/reasons for this we examined whether (1) different programmers would identify the same segment as “optimal”; and (2) the same programmer would select the same “optimal” segment over time. We hypothesized there would be a moderately high level of agreement on optimal electrode selection between different assessors and repeated assessments by the same evaluator.MethodsThis was a prospective, double‐blind investigation evaluating the reliability and stability of programming d‐DBS. Each patient underwent a mono‐polar survey four times (2 time points by 2 separate assessors). The primary aim was the inter‐rater agreement of selecting the optimal electrode at 1 and 6 months. The secondary aim was to determine the intra‐rater agreement of selecting the optimal electrode from 1 to 6 months.ResultsTwenty‐one patients were enrolled. There was fair inter‐rater agreement at 1 month and moderate at 6 months. There was minimal intra‐rater agreement between 1 and 6 months.DiscussionThe data refuted our hypothesis. Potential reasons for low agreement include (1) the arduous/subjective nature of identifying the optimal electrode in d‐DBS systems, especially in well‐placed electrodes; and/or (2) acute changes to the location of stimulation delivery offering temporary improvement in symptoms. Key takeaways gathered were it may, (1) behoove the programmer to explore different electrode montages after a period of time; and (2) be more efficient to review the directional electrode montage only when dictated by clinical symptoms/disease progression.