Diurnal modulation of subthalamic beta oscillatory power in Parkinson's disease patients during deep brain stimulation.
The brains of people with Parkinson's often show exaggerated electrical activity called beta rhythms, which are linked to slow movement. Here, we studied 24-hour recordings of deep brain activity over weeks, using devices implanted to treat symptoms with electrical stimulation. We show that the strength of beta rhythms is reliably reduced at night. This discovery could be used to improve stimulation-based treatments.
Beta-band activity in the subthalamic local field potential (LFP) is correlated with Parkinson's disease (PD) symptom severity and is the therapeutic target of deep brain stimulation (DBS). While beta fluctuations in PD patients are well characterized on shorter timescales, it is not known how beta activity evolves around the diurnal cycle, outside a clinical setting. Here, we obtained chronic recordings (34 ± 13 days) of subthalamic beta power in PD patients implanted with the Percept DBS device during high-frequency DBS and analysed their diurnal properties as well as sensitivity to artifacts. Time of day explained 41 ± 9% of the variance in beta power (p < 0.001 in all patients), with increased beta during the day and reduced beta at night. Certain movements affected LFP quality, which may have contributed to diurnal patterns in some patients. Future DBS algorithms may benefit from taking such diurnal and artifactual fluctuations in beta power into account.