Actigraphic assessment of sleep/wake behavior in central disorders of hypersomnolence

Objective: To evaluate the reliability of actigraphy to distinguish the features of estimated daytime and nighttime sleep between patients with central disorders of hypersomnolence and healthy controls. Methods: Thirty-nine drug-naïve patients with Narcolepsy Type 1, twenty-four drug-naïve patients with Idiopathic Hypersomnia, and thirty age- and sex- matched healthy controls underwent seven days of actigraphic and self-report monitoring of sleep/wake behavior. The following variables were examined: estimated time in bed (eTIB), estimated total sleep time, estimated sleep latency (eSOL), estimated sleep efficiency, estimated wake after sleep onset, number of estimated awakenings (eAwk), number of estimated awakenings longer than 5 minutes, estimated sleep motor activity (eSMA), number of estimated naps, mean duration of the longest estimated nap (eNapD), and daytime motor activity. Results: All actigraphic parameters significantly differentiated the three groups, except eTIB and eSOL. A discriminant score computed combining actigraphic parameters from nighttime (eSMA, eAwk) and daytime (eNapD) periods showed a wide area under the curve (0.935) and a good balance between positive (95%) and negative predictive (87%) values in Narcolepsy Type 1 cases. Conclusion: Actigraphy provided a reliable objective measurement of sleep quality and daytime napping behavior able to distinguish central disorders of hypersomnolence and in particular Narcolepsy Type 1. The nycthemeral profile, combined with a careful clinical evaluation, may be an ecological information, useful to track disease course.