0258 Posterior Spindle Density Moderates Overnight Discriminatory Attention Change in Children

Introduction Sleep spindles have been implicated in the stabilization of cognitive performance across sleep, yet their functional relevance in childhood remains poorly characterized. Because spindle topography and frequency undergo marked developmental changes - with slow spindles most prominent over posterior regions in early and middle childhood - region-specific spindle dynamics may be especially important for attention during this period. This study examined whether anterior (fast) versus posterior (slow) spindle density predicts overnight changes in attentional performance in children. Methods Forty-eight healthy children (ages 5–11) completed the Test of Variables of Attention (TOVA) in the evening (PM) and morning (AM) surrounding an overnight high-density EEG recording (256 channels). The primary outcome was TOVA d-prime from the first quarter, indexing discriminatory attention. Spindle density was quantified separately for anterior and posterior regions. Generalized Estimating Equations (GEE) tested the interaction between timepoints of TOVA performance (AM vs PM) and spindle density, controlling for age and gender. Results Overall, there was no significant change in absolute TOVA scores from PM to AM (β = –0.47, p = 0.20). However, children with higher posterior spindle density showed a more favorable overnight stabilization of attentional performance, reflected in a significant Time × Posterior Spindle interaction (β = 0.04, p = 0.04). Anterior spindle density did not moderate overnight change (β = 0.01, p = 0.20). As expected, older children showed significantly higher d-prime scores across timepoints (β ≈ 0.48, p < .01), while gender had no effect in either. Conclusion Posterior spindle density predicts the extent to which attentional discrimination is preserved across sleep in school-aged children. This regional specificity aligns with developmental neurophysiology: slow spindles are maximal over posterior cortex in childhood and may support stabilization of attention-related networks. These findings highlight the importance of region-specific sleep physiology in developmental attentional processes and motivate finer-grained analyses using spindle subtypes and additional TOVA metrics. Future research could clarify whether posterior spindle activity serves as a potential risk indicator for attentional difficulties in children. Support (if any)