Objective: Here we document the key advances and pitfalls of the Percept^TM PC (Medtronic), a commercially available device capable of recording brain local field potentials (LFP) from chronically implanted leads, wirelessly and during stimulation.

Background: The beta band (13-30Hz) power of the subthalamic nucleus (STN) is an established biomarker of Parkinson’s disease (PD) symptoms severity. A prerogative of new deep brain stimulation (DBS) devices is the capacity to record and process this biomarker to regulate and tailor the delivery of stimulation.

Method: 14 PD patients implanted in the STN received the Percept. We recorded STN LFP in different conditions of stimulation, medication and effort. Furthermore, we recorded the beta-band power of three patients for several weeks (one sample every two minutes) in their chronic at-home environment.

Results: Continuous LFP signals were reliably recorded from the implanted leads wirelessly on all patients. We performed Survey recordings in 11 patients and identified a beta peak in 19/22 STNs, at an average frequency of 22.6 (SD ±4.9Hz).

In three patients, we performed BrainSense recordings while titrating the stimulation amplitude and monitoring the upper limb rigidity. As the stimulation increased, the beta band power and rigidity decreased. Of importance, stimulation artefacts did not affect the beta band. However, in some patients, high power bands appeared in the gamma band at subharmonics (1/2, 1/4 or 3/4) of the stimulation frequency at high stimulation amplitudes.

Besides, recordings reliably captured expected beta-band power reduction with medication, stimulation, and the combination of both (one patient), and during a motor task with respect to rest (one patient).

Finally, in the three patients undergoing chronic home recordings, we observed a low level of beta power during sleep time compared to awake time.

Of note, some LFP recordings were sensitive to cardiac artefacts (in 20% of the patients), stimulation aliasing artefacts and movement artefacts.

Conclusion: The sensing capabilities of new DBS devices will help optimize the efficacy of existing therapies and foster new knowledge. They will contribute to simplifying the use of LFP sensing in everyday practice, whether to guide the selection of the optimal stimulation electrodes and amplitude, to identify novel biomarkers, or to enable closed-loop therapies.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/chronic-sensing-of-the-subthalamic-nucleus-in-parkinsons-disease-patients-preliminary-observations/