Selection of optimal programming contacts based on local field potential recordings from subthalamic nucleus in patients with Parkinson's disease

Abstract

Background: In the United States, the most commonly used surgical treatment for patients with Parkinson's disease is the implantation of deep brain stimulation (DBS) electrodes within the subthalamic nucleus. However, DBS device programming remains difficult and is a possible source of decreased efficacy.

Objective: We investigated the relationship between local field potential (LFP) activities in the subthalamic nucleus and the therapeutic response to programming.

Methods: We recorded LFPs with macroelectrodes placed unilaterally for DBS in 4 PD patients, 3 weeks after implantation, before the start of log-term DBS. Power-frequency spectra were calculated for each of 7 possible electrode contacts or contact pairs, over multiple 5- to 10-minute quiet waking epochs and over 30-second epochs during hand movements. Subsequently, DBS devices were programmed, with testing to determine which electrode contacts or contact pairs demonstrated optimal therapeutic efficacy.

Results: For each patient, the contact pair found to provide optimal efficacy was associated with the highest energy in the beta (13-32 Hz) and gamma (48-220 Hz) bands during postoperative LFP recordings at rest and during hand movements. Activities in other frequency bands did not show significant correlations between LFP power and optimal electrode contacts.

Conclusion: Postoperative subband analysis of LFP recordings in beta and gamma frequency ranges may be used to select optimal electrode contacts. These results indicate that LFP recordings from implanted DBS electrodes can provide important clues to guide the optimization of DBS therapy in individual patients.

Figures

FIGURE 1

Overview of experimental design. All subjects underwent local field potential (LFP) recording 3 weeks after electrode implantation, followed by implantable pulse generator (IPG) implantation surgery. All patients underwent testing in the on and off medication states. DBS, deep brain stimulation.

FIGURE 2

A, representative raw postoperative local field potential (LFP) data from a single subject. The vertical lines represent 1-second time intervals. Reconstruction of the location of contact E1 indicated that it was located within the borders of the subthalamic nucleus. Arrows indicate phase reversals between E0E1 and E1E2, suggesting that the oscillatory activity is locally generated. B, LFP spectra, from the same subject as in A, from 3 bipolar derivations (postoperative recordings), estimated over a 5-minute period during rest. The spectrum of each contact is normalized to the average energy of all contacts. Note that the bipolar derivation demonstrating peak β-band activity (E0E1; solid blue line) corresponds to the electrode contact pair associated with optimal benefit during programming (contact pair 0 and 1).

FIGURE 3

Box-and-whisker plots of the normalized β-band (13–32 Hz) power in decibel scale estimated from 4 monopolar (E0, E1, E2, and E3) and 3 bipolar (E0E1, E1E2, and E2E3) derivations, all simultaneously recorded under resting conditions in the off medication state. In each case, the montage with the highest β-band activity corresponded to the clinically most efficacious contacts (E0E1 in patients 1 to 3, E1E2 in patient 5).