Postdoctoral Scholar University of California San Francisco
Disclosure(s):
Hamid Fekri Azgomi, PhD: No financial relationships to disclose
Introduction: Gait abnormalities are common among individuals with Parkinson’s disease (PD) and are challenging to treat, given their variable response to medication and deep brain stimulation (DBS) therapy. Identifying effective stimulation parameters to improve gait functions can be particularly difficult, given the range of parameters that can be adjusted (stimulation frequency, amplitude, and pulse width). In addition, how different stimulation parameters affect the basal ganglia thalamocortical network during gait is unknown. In this research, we investigate the effects of changes in stimulation parameters on neural network activities involved with gait functions.
Methods: Here, we record local field potentials (LFPs) from the globus pallidus (GP) and premotor and motor cortex of 3 subjects with PD implanted with a bidirectional, investigational device (Summit RC+S, Medtronic). Patients perform over-the-ground walking while wearing wearable devices that can capture gait kinematic measurements under different stimulation conditions. We first aligned the neural data with the measurements from wearable devices and performed continuous wavelet transform on LFP recordings. We then utilized a Kruskal-Wallis test to analyze the effects of DBS stimulation parameters on gait-related measurements and LFP activities.
Results: We found that low-frequency stimulation (i.e., 60 Hz) results in improvements in different gait kinematics such as enhancing gait symmetry (p < 0.001) within similar gait cadence. These improvements are correlated with alteration in LFP signals which include a 34% increase in the theta band power of the motor cortex during double support time and a 21% increase in beta power during the swing phase. Analysis of premotor cortex activation also reveals a 45% increase in alpha power during the stance phase.
Conclusion : Our results support the hypothesis that different stimulation parameters alter pallidal-motor circuit activities which are associated with changes in gait kinematics. Future efforts to model LFP changes under different stimulation parameters may improve DBS programming for gait disorders in PD.
