Trigeminal Nerve Stimulation for Drug Resistant Epilepsy

Wednesday, March 6, 2013

In the journal Neurology articles ahead of print, Doctors DeGiorgio and colleagues from the Departments of Neurology, University of California Los Angeles and University of Southern California in Los Angeles, present a trial of trigeminal nerve stimulation for drug resistant epilepsy. Trigeminal nerve stimulation is a new stimulation technique designed for patients with epilepsy that have failed to respond to medications. This stimulation tool is a nonsurgical, noninvasive stimulator that has potential benefit for reducing seizures without a patient having to undergo surgery. This study tested the safety and effectiveness of trigeminal nerve stimulation device in patients with drug resistant epilepsy utilizing a randomized, double-blind design to test the suitability of treatment and assess side effects in preparation for a much larger study of the device. Of note, this device is already approved by the European Union and therefore this study is important for potential FDA approval in the United States.

The investigators enrolled 50 subjects with two or more partial onset seizures per month that were either complex partial or tonic-clonic, and measured over a six-week baseline period, then evaluated at 6, 12, and 18 weeks during an acute treatment period with the stimulator. Subjects were randomized to treatment to 120 Hz of the trigeminal nerve stimulation or a control parameter, which is essentially the device delivering almost no signal.

The individuals who were enrolled had highly drug resistant epilepsy with 8.7 seizures per month vs. a control group of 4.8 seizures per month. On average, subjects had failed more than three drugs prior to enrollment with a duration of epilepsy of 21.5 years in the treatment group and 23.7 years in the control group. Trigeminal nerve stimulation was well tolerated. Side effects included anxiety, headache, and skin irritation. The responder rate, defined as more than 50% reduction of seizure frequency, was 30.2% for the treatment group vs. 21.1% for the active control group for the 18-week treatment period, which was not found to be significant. The treatment group experienced a significant within group improvements in response rate over the 18-week treatment period. Subjects in the treatment group were more likely to respond than patients randomized to control. The trigeminal nerve stimulator was associated with reductions in seizure frequency, as measured by response ratio and improvements in mood based on a questionnaire known as the Beck Depression Inventory.

The authors concluded that there is preliminary evidence that trigeminal nerve stimulation is safe and may be effective in subjects with drug resistant epilepsy. Side effects were limited to anxiety, headache, and skin irritation and this information will help to form a basis for a larger multi-center Phase 3 clinical trial.

Trigeminal nerve stimulation, which has been supported partly by Epilepsy Therapy Project, is an interesting new noninvasive approach to seizure treatment. One important question remains to be settled which is can the device and its controls be set at a way that delivers the best seizure outcomes possible for individuals with drug resistant epilepsy. Clearly, much more needs to be addressed with regards to what happens with this device, but this is a positive, hopeful sign of a potentially new approach for treatment of epilepsy utilizing an externally based stimulator.

Authored by: Joseph I. Sirven MD on 3/2013
Learn more about the TNS from the June 15, 2009 Hallway Conversation

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