Effects of high-definition transcranial direct current stimulation for the treatment of chronic insomnia: a randomized, double-blind, controlled trial

To evaluate effects of 10-day high-definition transcranial direct current stimulation (HD-tDCS) over the dorsal medial prefrontal cortex (DMPFC) in patients with chronic insomnia. Fifty-five chronic insomnia patients were randomized into two groups: an active tDCS group received 10 days of active anode HD-tDCS stimulation, and a sham tDCS group received sham stimulation. A anode stimulation electrode was placed in Fz (10/20 system) which intend to target the bilateral hemisphere DMPFC, and four cathodes were placed at FPz, F3, Cz, and F4 (10/20 system). We performed polysomnography (PSG) and self-reported sleep scale evaluations before and after the stimulation sessions. Compared with the sham tDCS group, the active tDCS group showed decreases in Pittsburgh Sleep Quality Index (PSQI) scores. In exploratory studies, sleep onset latency (SOL) and sleep efficiency (SE) measured by PSG improved after treatment. We did not observe any tDCS effects on sleep stage ratio after intervention. HD-tDCS on the DMPFC is effective in sleep promotion and daily sleepiness recovery in patients with chronic insomnia. These findings demonstrate that HD-tDCS is a possibly promising therapy to supplement medication and cognitive behavioral therapy for chronic insomnia that requires replication and additional safety data.