〔Abstract〕 To investigate the effects of cranial electrotherapy stimulation (CES) with varying parameter configurations on sleep quality in patients diagnosed with chronic insomnia disorder. Methods Seventy-two partici- pants meeting diagnostic criteria for chronic insomnia disorder were randomly allocated to a four-arm parallel study design . The intervention protocol comprised : Group 1 (G1) received cranial electrotherapy stimulation (CES) at 0. 5 Hz , 300 μA; Group 2 (G2) underwent CES treatment at 1 . 5 Hz , 300 μA; Group 3 (G3) administered 100 Hz , 300 μA stimulation; and Group 4 (G4) received sham stimulation with identical device placement but no cur- rent delivery . Primary outcomes were quantified through polysomnography (PSG) recordings conducted at baseline and post-intervention , whereas secondary outcomes were assessed via standardized sleep questionnaires including the Pittsburgh sleep quality index (PSQI) and Insomnia Severity Index (ISI) . Results Following a 10-day inter- vention protocol , significant clinical improvements were observed across all active treatment groups ( G1 - G3) as evidenced by reductions in PSQI . Insomnia severity index ( ISI) scores quantitative polysomnographic analysis re- vealed that both G2 ( 1 . 5 Hz) and G3 ( 100 Hz) cohorts demonstrated statistically significant enhancements in Flinders Fatigue Scale (FFS) scores , total sleep time (TST) , and sleep efficiency (SE) , accompanied by reduced sleep onset latency ( SOL) compared to baseline measurements . However , no statistically significant differences were detected between the G2 and G3 intervention arms across all measured parameters . CES exerted no significant effect on sleep architecture . Conclusion CES can effectively improve the sleep of patients with chronic insomnia.Within a certain range , a higher frequency of CES leads to better sleep improvement effects .