Long-term recordings of local field potentials from implanted deep brain stimulation electrodes

Area of Science:

• Neuroscience
• Biomedical Engineering
• Neurology

Background:

• Deep brain stimulation (DBS) of the subthalamic nucleus is a key Parkinson disease treatment.
• Current DBS lacks responsiveness to individual disease state fluctuations.
• Local field potentials (LFPs) are explored as biomarkers for Parkinson disease state.

Purpose of the Study:

• Investigate LFP amplitude and movement response differences in acutely versus chronically implanted DBS electrodes.
• Assess changes in LFP activity over the long-term (2-7 years) following subthalamic nucleus DBS implantation.

Main Methods:

• Recorded LFPs at DBS surgery, 3 weeks post-implantation, and 2-7 years later during generator replacement.
• Calculated LFP power-frequency spectra from electrode derivations during rest and movement epochs.
• Analyzed monopolar impedance trends over time to assess electrode health.

Main Results:

• No significant difference in β-band LFP amplitude between acute implantation and 3-week post-implantation.
• β-band LFP amplitude was significantly lower at long-term follow-up compared to acute recordings.
• Impedance measurements showed a declining trend over the implant lifetime.

Conclusions:

• Long-term LFP recordings are feasible years after DBS implantation.
• LFPs retain similar movement response profiles over time, despite amplitude decrease.
• Findings support the development of closed-loop, responsive DBS systems utilizing LFPs.