Objective: Investigate cerebellar local field potentials (LFPs) associated with movement using DBS leads in patients with spinocerebellar ataxia.

Background: The Bereitschaftspotential (BP) detectable via EEG over cortical motor areas during voluntary movement is well-described,[1] but its generative source is not established, and has been hypothesized to involve widespread cortical and subcortical generators.[2] Corresponding movement-related potentials have been recorded using DBS in deep brain structures including the subthalamic nucleus [3] and thalamic ventrolateral nucleus.[4] Cerebellar DBS is currently being explored as a treatment for spinocerebellar ataxia (SCA) and other movement disorders, presenting an opportunity to analyze cerebellar LFPs associated with voluntary movement.

Method: 2 patients with SCA were implanted with bilateral DBS leads targeting the dentate nuclei. Prior to internalization and stimulation, patients underwent recording of LFPs from bilateral externalized leads as well as scalp EEG over Cz, C3, C4, Pz, Fz, Fp1, Fp2, and surface EMG over the extensor carpi radialis (ECR) muscles. Recording included self-paced voluntary wrist extension every 5-10 seconds for 10 minutes, one side at a time. Back-averaging of ECR surface EMG bursts with EEG and LFP data was performed.

Results: BP was present in the central scalp EEG leads in both patients. Externalized DBS lead recording from patient 1 was limited by artifact causing frequent upward drift in both cerebellar DBS leads, limiting the number of voluntary movements acceptable for back-averaging. Monopolar montage revealed a slowly rising potential in both cerebellar DBS leads in both patients, starting around 1-1.5 seconds before the voluntary wrist movement in patient 2, timing of onset was unclear in patient 1. Bipolar montage showed phase reversal in the right cerebellum in patient 2, this was less certain in patient 1 which may be due to the drift artifact.

Conclusion: Recordings from these first 2 patients suggest that movement-related potentials corresponding to the BP can be recorded using cerebellar DBS electrodes, similar to those seen in other deep brain structures. We anticipate recording from additional patients in the near future, expanding our analysis to include event-related synchronization and desynchronization, and investigating LFPs associated with more complex movements including motion capture measures of gait.

References: [1] 1. Hallett M, DelRosso LM, Elble R, et al. Evaluation of movement and brain activity. Clin Neurophysiol. 2021;132(10):2608-2638. doi:10.1016/j.clinph.2021.04.023
[2] 1. Rektor I. Scalp-recorded Bereitschaftspotential is the result of the activity of cortical and subcortical generators – a hypothesis. Clin Neurophysiol. 2002;113(12):1998-2005. doi:10.1016/s1388-2457(02)00286-9
[3] Paradiso G, Saint-Cyr JA, Lozano AM, Lang AE, Chen R. Involvement of the human subthalamic nucleus in movement preparation. Neurology. 2003;61(11):1538-1545. doi:10.1212/01.wnl.0000096021.28967.57
[4] Paradiso G, Cunic D, Saint-Cyr JA, et al. Involvement of human thalamus in the preparation of self-paced movement. Brain. 2004;127(12):2717-2731. doi:10.1093/brain/awh288

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MDS Abstracts - https://www.mdsabstracts.org/abstract/movement-related-potentials-recorded-using-cerebellar-deep-brain-stimulation-leads/