Abstracts

Rationale: There is biofeedback therapy utilizing electrodermal activity (EDA), which can reduce epileptic seizures. In this method, EDA is used as a sympathetic function and a subject is encouraged to increase his/her EDA. There has been no report about resting EDA in patients with epilepsy and we think that it would bring us the better method to execute biofeedback therapy. Then, we investigated and compared resting EDA from patients with epilepsy and normal controls. Methods: This research was cross-sectional observational study. Subjects were patient with epilepsy in the Department of Psychiatry and Neurology, Hokkaido University Hospital, Japan, and normal controls. For the measurement, wristband type EDA measuring instrument (E4 wristband®; empatica) was used. We measured resting EDA of both wrists in the dark and quiet room with a room temperature of 23°C, and a humidity of 60%, at 14 to 15 o’clock for 10 minutes. Statistical analysis was performed using logarithmically transformed EDA data. Results: We obtained data from 22 patients with epilepsy and 24 normal controls. There was no significant difference in age and sex. In the epilepsy group, there were 21 patients with focal epilepsy (14 patients with temporal lobe epilepsy), the number of seizures was 8.4 ± 23.5 times/month, the disease duration was 22.5 ± 21.5 years, and the number of drugs was 2.27 ± 1.87. In comparison between the epilepsy group and the control group, resting EDA tended to be lower in the epilepsy group (P = 0.12). When compared 18 patients except for 4 seizure-free patients from the epilepsy group with the control group, the resting EDA was significantly lower (P = 0.036). In the epilepsy group, the seizure frequency was significantly inversely correlated with the resting EDA (r = - 0.50, P = 0.016), while there was no significant correlation in disease duration and the number of drugs. Conclusions: In the epilepsy group resting EDA tended to be lower than the control group, and decreased as the number of seizures increased. This indicates lower sympathetic function at rest in patients with epilepsy. As a mechanism, repeated seizures may cause dysfunction in the limbic system - hypothalamus, which is responsible for sympathetic function. Funding: This work was supported by JSPS KAKENHI Grant Number 18K15505.