Distinct behavioral and electrophysiological correlates of sleep disturbance during verbal and spatial working memory tasks.

Associations between sleep disturbance and working memory (WM) vary across tasks and outcome measures. This study examined behavioral and electrophysiological correlates of subjective sleep disturbance during verbal working memory (VWM) and spatial working memory (SWM) in university students. Sixty-one participants were classified using Pittsburgh Sleep Quality Index (PSQI) scores into a sleep disturbance group (n = 28) and a normal sleep group (n = 33) and completed separate verbal and spatial 2-back tasks with event-related potential (ERP) recording. After adjustment for depression, anxiety, and stress, the sleep disturbance group showed lower VWM accuracy (ACC) (mean difference = -3.89 percentage points, 95% CI [-6.83, -0.96]) and discrimination sensitivity (d'). VWM false alarm rates (FAR) were also higher, although the absolute difference was small. Higher PSQI scores were associated with lower VWM ACC and d' and higher FAR. The sleep disturbance group showed lower VWM P3 amplitude averaged across the analyzed electrode sites and longer P3 peak latency at Oz. No significant group-related effects were detected for VWM median reaction time or N2 measures, or for SWM behavioral and ERP measures. These findings link subjective sleep disturbance to lower ACC and discrimination during verbal updating, accompanied by differences in later task-related electrophysiological processing. Future longitudinal and intervention studies with matched tasks and objective sleep measures could clarify the temporal and causal relationships underlying these associations.