0354 EFFECTIVENESS OF LOW-FREQUENCY ELECTRICAL STIMULATION ON PATIENTS WITH CHRONIC INSOMNIA

Although transcutaneous electrical nerve stimulation (TENS) was known as relieving neuromuscular pain, it has been rarely used to treat insomnia. The aim of this study was to investigate additional effects of low-frequency electrical stimulation on chronic insomnia. Fifty-four patients with chronic insomnia who took medications more than 6 months participated in the study, and they received TENS with low-frequency applied on trapeziums muscles (back and neck) via transcutaneous electrodes. They were required to apply the TENS for 30 minutes to an hour before taking sleep medications, more than 5 days per week, and for 4 weeks. Demographic characteristics, Pittsburgh sleep quality index (PSQI), insomnia severity index (ISI), Epworth sleepiness scale (ESS), hospital anxiety and depression scale (HADS) and quantitative EEG at wakefulness were evaluated before and after the treatment. Responders was defined when PSQI, ISI or ESS scores decreased more than 1standard deviation or dosage of medication was reduced after treatment. In 44 patients, poor sleep quality and insomnia severity at baseline decreased significantly after treatment (PSQI=12.53 ± 3.65 to 11.05 ± 3.73, p<0.001; ISI=13.48 ± 7.24 to 11.72 ± 5.98, p=0.006). Relative delta power in occipital region also decreased (15.08 ± 9.38 to 12.7 ± 10.56, p=0.038). Overall response rate was 57.5% and predictive factors of treatment response were excessive daytime sleepiness (OR=1.79, 95%CI=1.09–2.95, p=0.021), and depressive and anxious mood (OR=1.36, 95%CI=1.02–1.81, p=0.038) at baseline. A significant group-by-time interaction was observed in the relative delta power of occipital region between the two groups (responders=16.51 ± 9.69 to 14.52 ± 11.98; non-responders=13.66 ± 9.14 to 14.52 ± 11.98, F=5.806, p=0.024). Low-frequency electrical stimulation had additive positive effects on patients with chronic insomnia who were on medications. Daytime sleepiness, and depressive and anxious mood were predictors of treatment response and decreasing occipital delta power was associated with relieving insomnia symptoms. None.