Investigation of macro and micro sleep structures of first night effect in school-aged children.

This study aimed to investigate the occurrence and age-related changes of the first night effect (FNE) in school-age children using both macro (sleep architecture) and micro (frequency analysis) structures to polysomnography (PSG) data. PSG data from two consecutive nights were obtained from 38 healthy children aged 6-15 years. Sleep variables and power spectral analysis were compared between the two nights. The relationship between age and the difference in sleep variables and power values between the two nights was examined using correlation analysis. The first night showed significant reductions in total sleep time, sleep efficiency, N1, N2, and REM sleep, as well as significant increases in sleep onset latency and wake after sleep onset. The decrease in N3 and the increase in N2 due to FNE were positively and negatively correlated with age, respectively. Spectral analysis showed no effect of FNE for most variables, but there was a trend toward an increase in the convergence value of the δ band with age. FNE occurs in school-age children, and its manifestation changes with age. The decrease in N3 and increase in N2 become more pronounced with age, while the enhancement of low-frequency power is consistent across ages. These findings highlight the importance of considering age and specific sleep indicators when interpreting pediatric PSG results and underscore the need for a multi-level approach to understanding sleep changes across development.