Objective: To determine the reliability and stability of programming directional deep brain stimulation (d-DBS) systems.

Background: Conventional omni-directional deep brain stimulation (o-DBS) of the subthalamic nucleus is a proven therapy used to reduce symptoms of Parkinson’s disease (PD). The efficacy of o-DBS can be limited by side effects such as dysarthria and gait imbalance because of current spread to adjacent structures. Recently, d-DBS systems have emerged to overcome some of the limitations associated with o-DBS. D-DBS leads have the same four cylindrical electrode levels as in o-DBS systems, but the middle two electrodes are split into three individual segments that can be independently activated. This allows for “steering” of electrical current towards the intended target and away from neighboring structures offering improved clinical efficacy. The higher number of electrodes in d-DBS systems has led to a 1680-fold increase in electrode permutations, increasing programming complexity. To the best of our knowledge the stability and reliability of d-DBS electrode segment selection has not been determined. This is important because d-DBS will only be valuable if clinicians can reliably identify optimal stimulation parameters clinically.

Method: A prospective, observational, single-center clinical investigation to evaluate the reliability and stability of programming d-DBS is underway. Each patient will undergo a mono-polar survey 4 times at 2 time points (1 and 6 month) by 2 separate raters. The primary endpoint will be the inter-rater agreement of electrode selection at 1 month. Secondary endpoints will be inter-rater agreement of electrode selection at 6 months, intra-rater segment stability between 1 and 6 months, total electrical energy delivered calculations for best segment and ring, and ratio of ring versus segment selection. Up to 32 patients (n=32 brain hemispheres) will be enrolled. Cohen’s Kappa will be used to measure inter-rater agreement between best electrode (segment/ring) selection at 1 and 6 months. Fleiss’ generalized Kappa will be calculated to evaluate intra-rater reliability between 1 and 6 months. A p-value of < 0.05 will be considered statistically significant.

Results: Thirteen patients (26 brain hemispheres) have been recruited, and 12 (24 brain hemispheres) have completed their 1 month visits.

Conclusion: Final analysis (n=32) of the primary endpoint will be presented.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/reliability-and-stability-of-programming-directional-deep-brain-stimulation/