Abstracts

Trigeminal nerve stimulation (TNS) is a novel, potential alternative to vagus nerve stimulation for refractory epilepsy, presumably based on similar brainstem mechanisms. TNS has the advantage that a therapeutic trial can be undertaken noninvasively by transcutaneous stimulation, improving candidacy selection for an implantable device. This pilot study examines the effect of TNS on interictal spiking (effect on seizures has been reported separately [ndash] [italic]Neurology[/italic], in press).
Patient 1 had refractory complex partial seizures from head trauma. Interictal EEG revealed several epileptogenic foci, with a total average spike frequency of 3 per minute. A 2-hour EEG was recorded, with additional electrodes to monitor TNS over right and left maxillary nerves. Stimulation periods of 10-15 minutes alternated with control periods of similar length. Spikes were detected and amplitudes calculated by cross-correlation with normalized average spikes of each characteristic type.
Both mean and standard deviation of spike amplitudes showed a trend toward reduction during stimulation and return to baseline during control periods. TNS had no apparent effect on spike frequency.
TNS may exert a desynchronizing effect on neurons in an epileptic focus. We are in the process of replicating these findings in Patient 1 and extending the study to other patients.
[Supported by: Investigator-initiated grant, Advanced Bionics Corp.]