Objectives: Loss of control over online game use in gaming disorder (GD) is associated with diminished goal-directed executive control. Executive control can be measured as vagally-mediated heart rate variability (HRV) which
corresponds to variability in the in the intervals between heart beats. We hypothesized that individuals with GD would show different HRV responses during real-time gaming than those without GD, reflecting their diminished
goal-directed executive control.
Methods: Heart rate variability was assessed in 33 young males with GD and 29 controls while playing their favorite online game. Seed-based functional
connectivity (FC) was evaluated to assess unctional abnormalities in brain neural networks. A voxel-based morphometry (VBM) with diffeomorphic
anatomical registration using an exponentiated Lie algebra algorithm was conducted to assess gray matter volume (GMV). Afterwards, we tested
associations between HRV and alterations in FC and GMV.
Results: Game-related reactivity for high frequency (HF) HRV were significantly different between subjects with GD and the control group. Game related HF-HRV reactivity was correlated with the severity of GD and commission errors in continuous performance test. Compared with the control group, subjects with GD showed decreased FC between the right dorsolateral prefrontal cortex (DLPFC) and the right inferior frontal gyrus (IFG), corresponding to the central executive network. Subjects with GD showed
increased FC between the left dorsal caudal putamen and both sides of the postcentral gyrus, and also between the left dorsal rostral putamen and the left postcentral gyrus, reflecting increased FC in the sensorimotor network. Game related HF-HRV reactivity was correlated with DLPFC-IFG connectivity and dorsal caudal putamen-postcentral gyrus connectivity. Compared with control group, subjects with GD had smaller GMV in the right DLPFC.
Discussion: Young males with GD had phasic HF-HRV suppression during real-time gaming. This characteristic HRV was associated with the severity of GD, impulsivity, and FC alterations involving an imbalance between diminished FC in the central executive network and enhanced FC in the sensorimotor network. Our findings suggest that HRV measurements in young males with GD during real-time gaming reflect their habitual gaming behavior under diminished goal-directed executive control.