Category: Parkinson's Disease: Neurophysiology
Objective: To assess the stability of the daily distribution of peak subthalamic nucleus (STN) and globus pallidus internus (GPi) beta band power during continuous deep brain stimulation (DBS) in Parkinson’s disease (PD).
Background: STN and GPi local field potential (LFP) beta power (13-30 Hz) correlates with akinetic/rigid symptoms of PD [1-2], making it a frequently proposed feedback signal for adaptive DBS. Adaptive DBS systems typically assume the distribution of beta power remains stable over time, though this has not previously been well assessed over consecutive days. The recent availability of commercial DBS systems capable of sensing neural signals during stimulation now allows for characterization of how STN/GPi beta power may change longitudinally.
Method: Seven hemispheres (6-STN/1-GPi) from six subjects of the Medtronic-sponsored ADAPT-PD trial (NCT04547712) were studied. Hemispheres were analyzed if a 5 Hz band encompassing the peak STN/GPi beta activity at enrollment was monitored during the continuous DBS phase of the study. Beta band power was averaged every 10 minutes for 24-108 days, while medication and stimulation amplitude were held constant. Hemisphere-specific trends in daily median beta band power were assessed by linear regression. LFP signals were recorded with stimulation at 0 mA during study visits, from which the presence of electrocardiogram (ECG) artifact and its effect on beta power were assessed [3].
Results: Five of seven hemispheres had significant (p<0.05) drift in daily median beta power. The average magnitude of beta power drift per week was 5.2% ± 2.0% of the median beta power observed on the first day of analysis. Significant beta power drift was present in three hemispheres with ECG and two hemispheres without ECG artifact. In hemispheres with ECG, changes in artifact amplitude contributed to beta band power variability observed across study visits.
Conclusion: In this small cohort of patients with PD, multiple subjects/hemispheres experienced drift in the daily distribution of peak STN/GPi beta power during stable medication and continuous DBS conditions. It is unclear to what degree this drift is from physiologic variability reflecting clinical fluctuations versus artifact. Such drift has the potential to affect performance of adaptive DBS systems and prompt repeat programming / parameter optimization.
References: [1] Kühn AA, et al. Reduction in subthalamic 8-35 Hz oscillatory activity correlates with clinical improvement in Parkinson’s disease. Eur J Neurosci. 2006;23(7):1956-60.
[2] Weinberger M, et al. Oscillatory activity in the globus pallidus internus: comparison between Parkinson’s disease and dystonia. Clin Neurophysiol 2012;123:358–368.
[3] Hammer LH, et al. Artifact Characterization and a Multipurpose Template-Based Offline Removal Solution for a Sensing-Enabled Deep Brain Stimulation Device. Stereotact. Funct. Neurosurg. 2022.
To cite this abstract in AMA style:
L. Hammer, E. Yilmaz, S. Little, H. Zahed, M. Volz, S. Ravi, S. Wang, P. Starr, J. Ostrem. Stability of basal ganglia beta band power distribution during continuous deep brain stimulation in Parkinson’s disease: analysis of sub-cohort from the ADAPT-PD trial [abstract]. Mov Disord. 2023; 38 (suppl 1). https://www.mdsabstracts.org/abstract/stability-of-basal-ganglia-beta-band-power-distribution-during-continuous-deep-brain-stimulation-in-parkinsons-disease-analysis-of-sub-cohort-from-the-adapt-pd-trial/. Accessed November 23, 2024.« Back to 2023 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/stability-of-basal-ganglia-beta-band-power-distribution-during-continuous-deep-brain-stimulation-in-parkinsons-disease-analysis-of-sub-cohort-from-the-adapt-pd-trial/