The maintenance of wakefulness test (MWT) is used to objectively evaluate an individual’s ability to remain awake, however microsleeps are not included in the assessment. We aimed to determine if microsleep data prior to sleep onset assisted in interpretation of ability to maintain wakefulness across a range of typical patient groups.
Forty-eight patients referred for overnight polysomnography (PSG) and subsequent MWT were included. Patients were divided into three groups (treated OSA, untreated OSA or treated Idiopathic Hypersomnia or Narcolepsy (treated IH/Narc)) based on prior medical diagnosis. Demographics, clinical characteristics, PSG and MWT variables including frequency, distribution, duration and latency of microsleeps were compared between groups.
Microsleeps were observed in MWT trials significantly more frequently in treated IH/Narc patients over the course of the day (0.34 ± 0.06 vs 0.07 ± 0.02 microsleeps/min; p < 0.001) and in untreated OSA patients toward the end of the day (0.31 ± 0.06 vs 0.05 ± 0.02 microsleeps/min; p<0.001) compared to the treated OSA group. Microsleeps were often observed in series and earlier in treated IH/Narc (10.9 ± 1.6 minutes) and untreated OSA patients (16.2 ± 2.7 minutes) compared to the treated OSA group (24.9 ± 3.0 minutes; p<0.05), and if taken into consideration would increase the proportion of patients demonstrating inability to maintain wakefulness by 33% and 22% respectively.
MWT performance varies significantly across patient groups. Microsleep analysis prior to sleep onset may be a more sensitive measure of patient daytime wakefulness than sleep latency alone, and should be considered in MWT assessment.

© 2021 American Academy of Sleep Medicine.