Authors :
Presenting Author: Emma ACERBO, PhD – Emory University
Emma ACERBO, PhD – Emory University; Florian Missey, PhD – St Anne's Hospital Brno; Boris Botzanowski, PhD – Emory University; Stanislas Lagarde, MD, PhD – Aix Marseille Université; Fabrice Bartolomei, MD, PhD – Aix Marseille Université; Robert Gross, MD, PhD – Emory University; Daniel Drane, PhD – Emory University; Adam Williamson, PhD – St Anne's Hospital Brno
Rationale:
Electrical stimulation has gained increasing attention as a neuromodulation method in epilepsy treatment. Recently, Grossman et al. introduced a novel, non-invasive brain stimulation technique called temporal interference (TI). This method utilizes the application of two high-frequency electric fields ( >1KHz, f1 & f2) through external electrodes, generating a low-frequency stimulation amplitude modulation (Δf) that can target deep brain regions. A previous study that we published in mice demonstrated that TI stimulation at Δf=130Hz (f1=1300Hz, f2=1430Hz) applied to the hippocampus (HIP), where was located the epileptic focus, reduced the occurrence of fast ripples and inter-ictal spikes (IEDs). Building upon these findings, we aimed to investigate the effectiveness of this protocol in patients with temporal lobe epilepsy and compare it with a TI stimulation in the putative seizure onset zone (PSOZ). Additionally, we aimed to discern whether the therapeutic effect is attributed to the stimulation of the HIP or PSOZ.
Methods:
Patients with epilepsy underwent intracerebral multiple contact electrode insertion for stereoelectroencephalography (SEEG) exploration. SEEG signals were recorded using a digital system, with low-pass filtering, and patients were awake during the procedure. The first step was to place the stimulation electrodes (two pairs : f1=1300Hz, f2=1430Hz, Δf=130Hz) on the skin to target the HIP based on simulation-derived coordinates. Baseline recordings were conducted for 20 minutes, followed by 20 minutes of TI stimulation. The impact of TI stimulation was assessed by analyzing IEDs rates and characteristics (i.e., duration, amplitude, and area). Thus, stimulation electrodes were moved to target the PSOZ and the same protocol was applied.
Results:
During TI stimulation on the PSOZ, a significant two-fold reduction in the IED's rate was observed (Before vs. Stim and Stim vs. Post: p-value < 0.001; Before vs. Post: p-value = 0.27). Furthermore, TI decreased IEDs features, including area (Before vs. Stim: p-value < 0.001, Before vs. Post: p-value = 0.9, Stim vs. Post: p-value = 0.05), amplitude (Before vs. Stim: p-value = 0.006, Before vs. Post: p-value = 0.2, Stim vs. Post: p-value = 0.02), and duration (Before vs. Stim and Stim vs. Post: p-value < 0.001, Before vs. Post: p-value = 0.54). When the stimulation is performed in the HIP, outside of the PSOZ, we could not find any significant difference in the IED's rate.