P047 Using disruptions in sleep architecture to distinguish children with excessive daytime sleepiness

Abstract Background Diagnosing narcolepsy and idiopathic hypersomnolence (IH) requires an overnight polysomnographic (PSG) followed by a daytime multiple sleep latency test (MSLT). We aimed to identify markers in sleep macro-architecture on PSG which could distinguish between children with these conditions and those with subjective sleepiness but a negative MSLT and controls. Methods All children referred for a MSLT between May 2010 to December 2023 were eligible. Each child was matched for age and sex to a control. Wake stability was defined as the maintenance of a continuous series of wake epochs before transitioning to sleep and sleep stability as the maintenance of a particular sleep stage before waking or transitioning to another sleep state. The number and duration of epochs of each sleep stage was recorded. Results 28 children with narcolepsy, 11 with IH and 26 with subjective sleepiness were included. Children with narcolepsy exhibited higher levels of sleep stability as indicated by more sleep state changes and wake after sleep onset compared to their controls and to the subjectively sleepy group (p<0.001 for both). The number of REM epochs was greater in the narcolepsy group compared to their controls (p<0.001), the IH group (p<0.05) and subjectively sleepy group (p<0.05), while the average duration of REM epochs was shorter in the narcolepsy group compared to both the IH (p<0.05) and subjectively sleepy groups (p<0.05). Conclusions Our study suggests children with narcolepsy exhibit abnormalities in the stability of REM sleep which distinguishes them from those with IH and subjective sleepiness children.