Brain Anterior Nucleus of the Thalamus Signal as a Biomarker of Upper Voluntary Repetitive Movements in Epilepsy Patients

The Deep Brain Stimulation of the Anterior Nucleus of the Thalamus (ANT-DBS) is an effective treatment for refractory epilepsy. In order to assess the involvement of the ANT during voluntary hand repetitive movements similar to some seizure-induced ones, we simultaneously collected videoelectroencephalogram (vEEG) and ANT-Local Field Potential (LFPs) signals from two epilepsy patients implanted with the PerceptTM PC neurostimulator, who stayed at an Epilepsy Monitoring Unit (EMU) for a 5 day period. For this purpose, a repetitive voluntary movement execution protocol was designed and an event-related desynchronisation/synchronisation (ERD/ERS) analysis was performed. We found a power increase in alpha and theta frequency bands during movement execution for both patients. The same pattern was not found when patients were at rest. Furthermore, a similar increase of relative power was found in LFPs from other neighboring basal ganglia. This suggests that the ERS pattern may be associated to upper limb automatisms, indicating that the ANT and other basal ganglia may be involved in the execution of these repetitive movements. These findings may open a new window for the study of seizure-induced movements (semiology) as biomarkers of the beginning of seizures, which can be helpful for the future of adaptive DBS techniques for better control of epileptic seizures of these patients.