The Effect of Variable Deep Brain Stmiulation Frequencies on Balance and Gait in Patients with Either Subthalamic Nucleus(STN)or Globus Pallidus Internus (GPi)Deep Brain Stimulator: A Quantitative Analysis

OBJECTIVE: To study the effect of variable deep brain stimulation frequencies on balance and gait in patients with either bilateral Subthalamic nucleus(STN)or Globus pallidus internus (GPi)deep brain stimulator: A quantitative analysis.BACKGROUND:Gait and balance abnormalities are major contributor to falls in Parkinson Disease(PD)patients. Recent study indicates that low-frequency stimulation of STN or GPi improve gait in PD. In this study we quantitatively studied the effect of Low (LF-30Hz), intermediate (IF-80 HZ) and high frequency ( HF- clinically determined)DBS of STN and GPiMETHODS: We tested 10 patients (5 STN and 5 GPi). Subjects were first tested in their usual HF DBS settings. They were reevaluated twice at IF, and LF conditions in off-medications state after random selection of the sequence. Minimum of 30-minute wait period was allowed before evaluation after changing stimulation frequency.Quantitative gait parameters were obtained using Mobilty Lab portable gait syatem sensors. Motor impairements were tested using Unified Parkinson9s Disease Rating scale (UPDRS). Gait measure include stride length, speed, cadence, step duration, double support. Arm swing velocity, number of steps and turning duration.Result:Stride length improved in 5 patients on IF, 4 patients on HF and 1 patient on LF. Double support duration improved in 4 patients on IF, 3 patients on HF and 3 patients on LF. Cadence improved in 4 patients on IF, 3 patients on HF and 3 patients in LF stimulation. Gait stride velocity improved in 4 patients on IF and 4 patients on HF and 2patients on LF stimulation.CONCLUSIONS:The motor performance including gait and Balance deteriorated when the frequency of stimulation was changed from high-frequency to Intermediate(80Hz)or low frequency (30HZ). This clearly indicated by increase in UPDRS motor score. With respect to gait measures, in general, the lower frequency (30Hz) stimulation worsened gait and turning easures more than intermediate frequency Disclosure: Dr. Deep has nothing to disclose. Dr. Lieberman has nothing to disclose. Dr. Dhall has received personal compensation for activities with Impax, Merz Pharma, Acadia, Medtronic, and IO Therapeutics as a consultant and for activities with Impax, UCB Pharma, Teva Neuroscience as a speaker. Dr. Shafer has nothing to disclose. Dr. Tateuchi has nothing to disclose. Dr. Simpson has nothing to disclose. Dr. Frames has nothing to disclose.