The Interplay Between Sleep Disturbance, Glymphatic Dysfunction and Altered Brain Networks in Internet Gaming Disorder: A Multimodal Neuroimaging Study

Sleep disturbances are common in individuals with Internet gaming disorder (IGD), yet the neurobiological links between poor sleep quality and addictive symptoms remain unclear. The glymphatic system contributes to cerebrospinal fluid-interstitial fluid exchange and metabolic waste clearance, processes that are closely related to sleep physiology. Diffusion tensor image analysis along the perivascular space (DTI-ALPS) provides a non-invasive MRI-based marker related to glymphatic system function. In parallel, middle frontal gyrus (MFG)-centred functional connectivity may reflect prefrontal network alterations associated with cognitive control and addiction severity in IGD. The study included 30 individuals with IGD and 37 demographically matched healthy controls (HCs). All participants underwent diffusion tensor imaging and resting-state functional MRI. DTI-ALPS was used to assess glymphatic system-related function. Resting-state functional connectivity analysis was performed using the MFG as the seed region. Group differences in ALPS indices were tested while controlling for age, education years and mean framewise displacement. Within the IGD group, correlation analyses were conducted to examine associations among ALPS indices, PSQI scores, MFG-centred functional connectivity and IAT scores. Individuals with IGD showed significantly lower mean and left ALPS indices than HCs. The right ALPS index showed a non-significant trend towards reduction. Within the IGD group, higher PSQI scores were associated with lower mean, left and right ALPS indices, suggesting that poorer subjective sleep quality was related to reduced glymphatic system-related function. MFG-centred functional connectivity analysis showed increased connectivity mainly involving medial and superior frontal regions and decreased connectivity involving subcortical regions. Stronger MFG-centred functional connectivity was positively correlated with IAT scores, indicating an association with greater addiction severity. This study integrates DTI-ALPS and MFG-centred resting-state functional connectivity to examine sleep-related glymphatic alterations and prefrontal network changes in IGD. Lower ALPS indices were associated with poorer sleep quality, whereas stronger MFG-centred connectivity was associated with greater addiction severity. These findings support a potential sleep-glymphatic-prefrontal network framework for understanding IGD. Longitudinal and interventional studies are needed to clarify the directionality of these associations.