Abstracts

Rationale: Suppression of cortical excitability or Long Term Depression (LTD) can be achieved with slow (1 Hz or 0.5 Hz) electrical pulses applied to the cortex.  We used noninvasive electrical pulses with a dense (256-channel) sensor array with the GTEN technology, targeted to the patient’s presumed epileptic focus as identified from electrical source localization of interictal discharges (spikes).  Methods: In four patients with drug-resistant epilepsy, treatment was applied with slow (0.5 Hz) pulses (100 ms; limited to 2 mA), with head surface source-sink electrode patterns chosen to optimize the cortical-surface-cathodal current delivery at the cortical site of the patient’s spikes.  For each of 5 successive days, the treatment protocol started with a baseline dEEG recording, three 17-minute trains of 500 pulses each, with trains separated by a 10 minute rest interval.  Continued dEEG recording allowed the assessment of the post-treatment spike rate, and it assured there was no worsening of epileptiform activity before the patient was sent home.  Results: For the first four patients reported here, spikes were suppressed on 9 of the 10 total days of treatment.  With spike rate as the dependent variable and days as the observations, a paired comparison one-tailed t-test showed the effect to be significant for Patient 1 (p < .001), Patient 2 (p < .02)  Patient 3 (p < .04), and Patient 4 (p < .02). Conclusions: Transcranial electrical neuromodulation with slow 2 mA pulses was found to be safe and well tolerated in the first four patients we have examined, as confirmed by dense array EEG (dEEG) review during and after treatment.  Acute suppression of spike rate was statistically significant for each patient.  Follow up for spike and seizure suppression over six months is ongoing. Funding: Funded by EGI.