Characterizing disrupted nighttime sleep and associated functional outcomes in youth with narcolepsy type 1.

Study objectives: Disrupted nighttime sleep (DNS) and sleep instability are common in children and adolescents with Narcolepsy Type 1 (NT1), but optimal objective sleep measures have not been determined. We compared self-reported and objective sleep measures between young people with NT1 and healthy controls (HC) and test the hypotheses that the Wake/N1 Index is the best objective measure of perceived nocturnal wakings vs. other DNS measures reported in the literature and is associated with daytime functional problems.

Methods: N=26 HC and N=27 NT1 participants ages 8-21 years completed a 15-item habitual sleep quality survey and an in-lab polysomnogram. We compared group survey responses and performed stepwise regression of sleep quality and instability measures with a survey question ("During the night, I wake more than once"). Last, we used logistic regression to identify associations between the Wake/N1 Index with daytime functional concerns across groups.

Results: Compared to HC, NT1 participants reported more frequent restless sleep, nighttime moaning/groaning/talking, tossing and turning, and nocturnal wakings (all p's < 0.01), but no greater difficulties in falling asleep or returning back to sleep. Across groups, self-reported waking from sleep was associated with increased Wake/N1 Index and SSRI/SNRI use. The Wake/N1 Index was associated with daytime fatigue but no other behavioral or cognitive concerns.

Conclusions: DNS is a multi-factorial complaint that differs from insomnia. We believe the Wake/N1 Index is a useful sleep instability measure that should be helpful in research and as a treatment target in clinical practice, especially for fatigue concerns.