Transkutane Vagusnervstimulation

Background

Approximately 20-40?% of epilepsy patients show drug resistance and a large number of patients under antiepileptic therapy suffer from side effects including cognitive disorders and depression. Transcutaneous vagus nerve stimulation (t-VNS) can be used for these patients as a supplementary treatment to resection epilepsy surgery.

Aim

The main aims of this investigation were to test the safety, tolerability and practicality of t-VNS in epilepsy patients.

Material and methods

For the proof of concept trial ten patients with pharmacoresistant epilepsy (eight with focal and two with generalized epilepsy) were recruited. For admission to the study a minimum frequency of four seizures per month was necessary. The medication dosage was kept constant in the baseline and in the total treatment phase. The auricular branch of the vagus nerve (ABVN) of the left ear was stimulated. The stimulation pulses were biphasic with a frequency of 10/s and a pulse width of 300 µs. After an initial training period the stimulation was carried out in the morning, midday and evening for 1 h each over a period of 9 months. The subjectively experienced frequency of seizures, continuous video EEG (electroencephalogram) long-term conduction carried out 4 times for 1 week each and cognitive and functional alterations were considered to be end point parameters.

Results

The total treatment period of 9 months was completed by seven patients. Of these seven patients five showed a reduction in the frequency of seizures during the 9-month treatment period and two reported an increase in seizures. In two patients the seizure frequency was reduced by 45 % and 48 % in a comparison between baseline and end of treatment. In two further patients contradictions arose between the subjective report on seizure frequency and the objectively quantified frequency in the video EEG. For one patient the interictal epileptic EEG activity was continually reduced during the course of the 9-month period.

Conclusion

The t-VNS procedure represents a procedure which is well tolerated and practical for long-term treatment.