TMS timed to interictal epileptiform discharges.

Area of Science:

• Neuroscience
• Epileptology
• Biomedical Engineering

Background:

• Interictal epileptiform discharges (IEDs) are unpredictable brain activity bursts between seizures in epilepsy patients.
• Targeting stimulation to IED onset is challenging but could offer insights into epileptic networks and improve neurostimulation therapies.

Purpose of the Study:

• To assess the feasibility of triggering transcranial magnetic stimulation (TMS) by IEDs in children with self-limited epilepsy with centrotemporal spikes (SeLECTS).
• To investigate the impact of IEDs on TMS-evoked potentials (TEPs) when stimulating the motor cortex.

Main Methods:

• A convolutional neural network (CNN) was trained on electroencephalography (EEG) data to detect IEDs in real time.
• An EEG-processing pipeline integrated the CNN to trigger TMS pulses during IED or non-IED periods.
• TMS was applied to the IED-generating motor cortex and the contralateral motor cortex in two pediatric participants.

Main Results:

• The study demonstrated the feasibility of timing TMS to IEDs.
• A site-specific increase in TEP amplitude was observed when stimulation occurred during IEDs.
• Successful IED-triggered TMS delivery rates were 39% and 19% for the two participants.

Conclusions:

• IED-triggered TMS is feasible in pediatric epilepsy, providing a foundation for brain-state-dependent stimulation.
• This approach holds promise for advancing epilepsy research and optimizing neurostimulation treatments.
• Methodological challenges were identified, with proposed solutions for future research in brain-state-dependent TMS for epilepsy.