Abstracts

Rationale: Epilepsy is a neurological disorder that affects approximately one percent of the world population of which 75% are from developing countries. Anti-epileptic drugs are ineffective in 25-30% of the epileptic patients. Electrical stimulation to control seizures may be an additive therapy which has shown promise in ongoing research. Methods: Ten Sprague-Dawley rats were used in the current study. Three custom designed tri-polar concentric ring electrodes were placed on the scalp with conductive paste and adhered using dental acrylic cement. Seizures were induced with pentylenetetrazole (PTZ) and EEG signals were recorded. Three animals were used as controls with the other seven receiving noninvasive transcutaneous electrical stimulation (TcES). The seizure synchronous activity was measured by coherence in the EEG recorded between electrodes. Results: The controls showed a significantly increased beta-gamma activity synchrony after PTZ injection and gradually increased even further with time compared to baseline beta-gamma activity. This beta- gamma activity synchrony during seizures was significantly reduced similar to the baseline recordings after treating the rats with TcES. The noninvasive TcES was able to significantly reduce (p<0.01) seizure activity synchrony. Conclusions: The beta/gamma electrographic activity can be detected on the scalp surface of seizing rats with tripolar concentric ring electrodes. Our data shows that TcES reduces pathologically increased synchrony at beta/gamma frequencies and this may contribute to the TcES ability to reduce or eliminate seizures caused by PTZ as well as other convulsants, as we have demonstrated previously.