The actigraphic evaluation of daytime sleep in central disorders of hypersomnolence: comparison with polysomnography.

STUDY

objectivesThe role of actigraphy in central disorders of hypersomnolence (CDH) is expanding but evidence of reliability with polysomnography (PSG) is scarce and provided only during nighttime. We explored the agreement between actigraphy and continuous 24-hour PSG at CDH diagnosis.

methodsForty-four consecutive drug-naïve patients (28 narcolepsy and 16 idiopathic hypersomnia [IH]) underwent actigraphy during 24 hours of free-running PSG, during multiple sleep latency test (MSLT) and 13 of them also during maintenance of wakefulness test (MWT). Daytime and nighttime sleep features and MSLT and MWT mean sleep latencies (mSL) were estimated with the actigraphic algorithms by Cole-Kripke (CK), Sadeh (Sad), and University of California San Diego (UCSD). Agreement to corresponding PSG measures was assessed with Bland-Altman plots.

resultsNighttime-total sleep time (TST) in narcolepsy was significantly underestimated with CK (bias 27.8 minutes, 95% CI 13.7 to 41.9) and Sad (bias 56.7 minutes, 95% CI 38.8/74.5). Daytime-TST was overestimated in IH and narcolepsy with all algorithms (CK: bias -42.2, 95% CI -67/-17.4; Sad: bias -30.2 minutes, 95% CI -52.7/-7.7; UCSD bias -86.9 minutes, 95% CI -118.2/-55.6). 24-hour-TST was overestimated by CK and UCSD in IH (CK: bias -58.5 minutes, 95% CI -105.5/-11.5; UCSD: bias -118.8 minutes, 95% CI -172.5/-65), and by UCSD in narcolepsy (bias -68.8 minutes, 95% CI -109.3/-38.2). In the entire cohort, actigraphy overestimated MSLT mSL but not MWT mSL.

conclusionsConventional actigraphic algorithms overestimate 24-hour TST in IH and underestimate nighttime TST in narcolepsy. These discrepancies call for the cautious application of actigraphy in the diagnostic process of CDH and the development of new quantitative signal analysis approaches.