2018 Volume 35 Issue 5 Pages 637-640
A 61–year–old female with advanced Parkinson disease underwent implantation of a deep brain stimulator into the subthalamic nucleus with directional lead and multiple current control technology. The patient's motor fluctuation was abolished by conventional monopolar stimulation with a cylindrical cathode ; however, she complained of dysarthria and postural instability one week after discharge. An investigation of current thresholds and adverse effects identified the responsible contacts―the anteroventral contact for dysarthria, the posteroventrolateral contact for hemibody dysesthesia, and the posteroventral contact for eyelid dullness. Using directional current steering, four different stimulation programs were tested to resolve the dysarthria by steering the current towards the dorsal and posterior directions. After several repetitive adjustments and trials, the patient finally selected the program that featured current distribution of 30% in the dorsal direction and 60% in the posterolateral direction. Based on a subjective assessment, this program was optimal, helping to resolve the dysarthria and dysesthesia, and producing minimal postural instability and best motor performance. Our findings suggest that directional current steering provides optimal therapeutic efficacy with minimal adverse effects.
