Microsleep versus Sleep Onset Latency during Maintenance Wakefulness Tests: Which One Is the Best Marker of Sleepiness?

Abstract

The interpretation of the Maintenance Wakefulness Test (MWT) relies on sleep onset detection. However, microsleeps (MSs), i.e., brief periods of sleep intrusion during wakefulness, may occur before sleep onset. We assessed the prevalence of MSs during the MWT and their contribution to the diagnosis of residual sleepiness in patients treated for obstructive sleep apnea (OSA) or hypersomnia. The MWT of 98 patients (89 OSA, 82.6% male) were analyzed for MS scoring. Polysomnography parameters and clinical data were collected. The diagnostic value for detecting sleepiness (Epworth Sleepiness Scale > 10) of sleep onset latency (SOL) and of the first MS latency (MSL) was assessed by the area under the receiver operating characteristic (ROC) curve (AUC, 95% CI). At least one MS was observed in 62.2% of patients. MSL was positively correlated with SOL (r = 0.72, p < 0.0001) but not with subjective scales, clinical variables, or polysomnography parameters. The use of SOL or MSL did not influence the diagnostic performance of the MWT for subjective sleepiness assessment (AUC = 0.66 95% CI (0.56, 0.77) versus 0.63 95% CI (0.51, 0.74)). MSs are frequent during MWTs performed in patients treated for sleep disorders, even in the absence of subjective sleepiness, and may represent physiological markers of the wake-to-sleep transition.

Sleepiness should be reinvestigated through the lens of clinical neurophysiology: A mixed expertal and big-data Natural Language Processing approach

“…In this way, pioneering works explored the genetic link to narcolepsy [34] and the role of orexin in narcolepsy [40]. Moreover, the link between sleepiness and circadian rhythms [13] and homeostatic pressure [1,66], have provided experimental evidence to the Borbélys' model of interplay between homeostatic processes and circadian rhythm that was theorized as early as 1982 [10] [30], the microstate analysis during MWT [5,16], or the study of stage transitions [17,35] represent metrics closely related to neurophysiology that can be extracted from electrophysiological signals already measured in sleep clinics, in order to investigate brain mechanisms related to sleepiness.…”

Revisiting the maintenance of wakefulness test: from intra‐/inter‐scorer agreement to normative values in patients treated for obstructive sleep apnea

“…It was also shown that the MWT was better correlated with performance on driving simulator than the Multiple Sleep Latency Test (MSLT) (Pizza et al, 2009) and that driving simulator performance had a good correlation with real driving performance although not perfect (Philip et al, 2005). However, several questions remain unsolved, such as the prevalence, normative latencies, and meaning of microsleep episodes often recorded during the MWT and the dynamics of sleepiness over time (and thus the recommended periodicity of sleepiness assessment) (Boyle et al, 2008; Des Champs de Boishebert et al, 2021; Hertig‐Godeschalk et al, 2020; Morrone et al, 2020). Interestingly, we observed that an ESS score of ≥11 but not an AHI of ≥15 events/h was associated with lower MSL, which is in line with previous finding about association subjective sleepiness, impaired driving performance, and history of car crash (Budhiraja et al, 2017; Pizza et al, 2009).…”

Interest of the BLAST paradigm and salivary markers for the evaluation of sleepiness in drivers

“…The present study has some limitations. First, the social desirability bias may have influenced the assessment of subjective sleepiness (Des Champs de Boishebert et al, 2021 ) and the strong association between chronic and acute sleepiness precludes distinguishing the effect of each independently on neurocognitive and biological markers. Then, drivers' sleepiness could have been influenced by non-controlled confounding factors such as undiagnosed or unreported sleep or mood disorders (e.g., sleep-disordered breathing, depression).…”

“…Although subjective techniques, such as scales and questionnaires, are attractive due to their ease of use and low cost, they are sensitive to inter- and intra-individual variability. They also do not represent reliable diagnostic tools as it has been shown that it is particularly difficult to correctly perceive and self-report sleepiness (Van Dongen et al, 2004 ; Schreier et al, 2015 ; Dauvilliers et al, 2017 ; Peter-Derex et al, 2020 ; Des Champs de Boishebert et al, 2021 ). Conversely, objective techniques such as the Multiple Sleep Latency Test (MSLT) or Maintenance of Wakefulness Test (MWT), which can only be performed in few sleep laboratories, are time-consuming, far from real-life conditions, and do not correlate with subjective measures (Wise, 2006 ; Peter-Derex et al, 2020 ).…”

“…Conversely, objective techniques such as the Multiple Sleep Latency Test (MSLT) or Maintenance of Wakefulness Test (MWT), which can only be performed in few sleep laboratories, are time-consuming, far from real-life conditions, and do not correlate with subjective measures (Wise, 2006 ; Peter-Derex et al, 2020 ). Moreover, while these different measures are sensitive to sleep propensity, they do not detect the rapid physiological changes (micro or local sleeps) associated with sleepiness and which can lead to brief attentional lapses under certain conditions, increasing performance instability (Doran et al, 2001 ; Peiris et al, 2006 ; Lim and Dinges, 2008 ; Andrillon et al, 2019 , 2021 ; Des Champs de Boishebert et al, 2021 ). Other measures, such as the Psychomotor Vigilance Test (PVT), can assess the quality of vigilance and are sensitive to microsleeps (Lim and Dinges, 2008 ) but only provide an overall estimate of attentional performance, falling to capture the moment-to-moment attentional state (Petton et al, 2019 ; Thieux et al, 2019 ).…”