Beta Power Response After Levodopa Intake in Parkinson's Disease Patients With Chronic Sensing-Enabled Deep Brain Stimulation.

Objective: In Parkinson's disease (PD), the power of beta oscillations (± 13-30 hertz [Hz]) from subthalamic nucleus (STN) local field potentials (LFPs) is associated with motor symptoms. Beta power can be used for adaptive deep brain stimulation (aDBS) algorithms based upon symptom fluctuations. The time course of beta power modulations after levodopa intake at home remains to be described.

Methods: Ten-minute averages of beta peak power were recorded in 33 patients with PD treated with STN-DBS for a median duration of 134 days during the titration phase. Median beta power after scheduled medication intakes (n = 24,103) and the effects of peak frequency, stun effect, stimulation amplitude, levodopa dose, and preoperative levodopa response were analyzed using cluster-based permutation testing.

Results: Beta power was significantly reduced between 30 and 140 minutes after intake for stimulation amplitudes between 0 and 2.1 mA (p < 0.01). This response was seen in low (12.7-20.5 Hz) but not high (21.5-30.3 Hz) beta frequencies. Significant clusters were found regardless of stun effect and preoperative levodopa response, during low stimulation amplitudes (< 1 mA), and for 100 and 150 mg but not 50 mg doses. A linear mixed-effects model for the area under the curve (AUC) levodopa beta response (30-180 min) revealed a dose-response relationship, a stronger negative response in low-beta compared with high-beta frequencies, and no significant effect of stimulation amplitude.

Interpretation: STN beta power responds to levodopa during low to moderate stimulation amperages, depending on the beta peak frequency and dose, which is informative for aDBS implementation. ANN NEUROL 2025.