Time dependent subthalamic local field potential changes after DBS surgery in Parkinson's disease

Area of Science:

• Neuroscience
• Biomedical Engineering
• Neurology

Background:

• Local field potentials (LFPs) offer physiological insights into the human basal ganglia via electrodes used in deep brain stimulation (DBS) for Parkinson's disease (PD).
• LFPs are typically recorded days after electrode implantation, a period termed "acute," potentially missing post-surgical tissue changes relevant to signal interpretation.

Purpose of the Study:

• To investigate how electrode impedance and LFP patterns change over time, from immediately after surgery to one month post-implantation.
• To determine if acute LFP recordings are representative of chronic LFP recordings in PD patients undergoing DBS.

Main Methods:

• LFPs and electrode impedances were recorded from 11 PD patients at four time points: immediately after surgery (T-0h), 2 hours after (T-2h), 2 days after (T-48h), and 1 month after (T-30d).
• Statistical analyses were performed to compare impedance and LFP power in different frequency bands across these time points.

Main Results:

• Electrode impedances were significantly higher at T-0h compared to all later time points.
• A decrease in the 2-7 Hz frequency band correlated with impedance changes.
• The 8-20 Hz and 21-35 Hz beta bands increased over time, stabilizing between T-48h and T-30d.

Conclusions:

• DBS electrode impedance and LFP patterns are time-dependent, influenced by the interval between implantation and recording.
• Changes in impedance and low-frequency bands may relate to the electrode/tissue interface, while beta band modulations suggest neural circuit adaptation.
• LFP analysis in the acute post-operative period is comparable to the chronic condition, supporting the use of LFPs in closed-loop DBS systems.