Efficacy and mechanisms of repeated closed-loop auditory exposure during slow-wave sleep for internet gaming disorder

Internet Gaming Disorder (IGD) is marked by impaired psychological and social functioning but remains without effective treatments. Cue exposure therapy (CET) is typically administered during wakefulness to help extinguish addictive memories. However, recent studies suggest that sleep may be an optimal state for memory modulation. This study aimed to assess the efficacy of repeated closed-loop exposure to game sounds during UP-state of slow-wave sleep (SWS) on IGD. 84 participants meeting DSM-5 criteria for IGD were randomly assigned to sleep intervention/control groups (SIG/SCG) or awake intervention/control groups (AIG/ACG) with two consecutive days of intervention. During SWS of two intervention nights, around 300 sounds were exposed at slow-wave UP-state. While the awake groups received similar auditory cue exposure during the awake state for two consecutive days. Cravings, playtime, and P300 amplitude in the cue reactivity task were recorded at baseline, post-intervention, and follow-up intervals (1, 2, 3, weeks, and 1 month). Results showed that the SIG significantly reduced cravings (p < 0.001), and playtime (p = 0.009) at post-intervention and follow-up, whereas awake CET showed no effect. The SIG exhibited higher low-frequency and early spindle power, along with lower late spindle power after sound exposure. Notably, the linear increase in sound-elicited late spindle power across the 20 intervention blocks over two experiment nights was positively correlated with reduced cravings post-intervention (r = 0.54, p = 0.015), especially among participants achieving a craving reduction greater than 30% after one month. Our findings suggest that closed-loop auditory exposure during SWS presents a promising, non-invasive intervention strategy for treating IGD, potentially exerting its effects by modulating late spindle power.