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Long-term Recordings of Local Field Potentials From Implanted Deep Brain Stimulation Electrodes

Abosch, Aviva MD, PhD*; Lanctin, David BS*,‡; Onaran, Ibrahim MS, MA*,§; Eberly, Lynn PhD; Spaniol, Maggie MS*; Ince, Nuri Firat PhD*,§

doi: 10.1227/NEU.0b013e3182676b91
Research-Human-Clinical Studies

BACKGROUND: Deep brain stimulation (DBS) of the subthalamic nucleus is an effective treatment for Parkinson disease. However, DBS is not responsive to an individual's disease state, and programming parameters, once established, do not change to reflect disease state. Local field potentials (LFPs) recorded from DBS electrodes are being investigated as potential biomarkers for the Parkinson disease state. However, no patient data exist about what happens to LFPs over the lifetime of the implant.

OBJECTIVE: We investigated whether LFP amplitude and response to limb movement differed between patients implanted acutely with subthalamic nucleus DBS electrodes and patients implanted 2 to 7 years previously.

METHODS: We recorded LFPs at DBS surgery time (9 subjects), 3 weeks after initial placement (9 subjects), and 2 to 7 years (median: 3.5) later during implanted programmable generator replacement (11 sides). LFP power-frequency spectra for each of 3 bipolar electrode derivations of adjacent contacts were calculated over 5-minute resting and 30-second movement epochs. Monopolar impedance data were used to evaluate trends over time.

RESULTS: There was no significant difference in β-band LFP amplitude between initial electrode implantation (OR) and 3-week post-OR times (P = .94). However, β-band amplitude was lower at implanted programmable generator replacement times than in OR (P = .008) and post-OR recordings (P = .039). Impedance measurements declined over time (P < .001).

CONCLUSION: Postoperative LFP activity can be recorded years after DBS implantation and demonstrates a similar profile in response to movement as during acute recordings, although amplitude may decrease. These results support the feasibility of constructing a closed-loop, patient-responsive DBS device based on LFP activity.

ABBREVIATIONS: DBS, deep brain stimulation

IPG, implanted programmable generator

LFP, local field potential

MAC, monitored anesthesia care

mUPDRS, Unified Parkinson's Disease Rating Scale

OR, initial electrode implantation

PD, Parkinson disease

PostOR, initial generator implantation (3-4 weeks after initial electrode implant)

RMS, root mean square

STN, subthalamic nucleus

*Department of Neurosurgery, University of Minnesota, Minneapolis, Minnesota

Division of Epidemiology, School of Public Health, University of Minnesota, Minneapolis, Minnesota

§Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota

Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, Minnesota

Correspondence: Aviva Abosch, MD, PhD, Department of Neurosurgery, University of Minnesota, D429 Mayo Memorial Building, 420 Delaware St SE, Minneapolis, MN 55414. E-mail: aabosch@umn.edu

Received January 23, 2012

Accepted June 12, 2012

Copyright © by the Congress of Neurological Surgeons