Page 99 - The autoimmune hypothesis of narcolepsy and its unexplored clinical features M.S. Schinkelshoek

Introduction
Sleep state misperception (or paradoxical insomnia) is common in chronic insomnia with a prevalence ranging between 9 and 50% (Bastien et al., 2014, Moon et al., 2015). The International Classification of Sleep Disorders, Second Edition (ICSD-2) defined sleep state misperception as a ‘consistent marked mismatch between objective findings from polysomnography (PSG) or actigraphy and subjective self-report or sleep diary’, but this concrete phrasing as a mismatch between objective and subjective measures has not returned in the ICSD-3 (ICSD, 2005, ICSD, 2014). Sleep state misperception has also been reported in other sleep disorders, such as obstructive sleep apnea (OSA), and in the general population (Castillo et al., 2014, Choi et al., 2016, Trajanovic et al., 2007). Most performed studies depend on nocturnal polysomnography for identifying sleep state misperception and finding patient-related predictors. Additionally, the focus is mainly on the situation in which subjective sleep time is lower than objective sleep time (classical sleep state misperception), while reverse sleep state misperception is not reported. Interestingly, sleep state misperception during daytime naps has not been well-studied.
Except for one study in OSA (Bishop et al., 1998), studies on sleep state misperception in sleep disorders with excessive daytime sleepiness (EDS) are absent, even though knowledge about sleep state perception seems highly relevant in the assessment of daily functioning for both the patient and the physician. Information about daytime sleep state perception could be an important addition to parameters such as subjective and objective sleepiness for the evaluation of disease severity, treatment decisions and fitness to drive (Liu et al., 2018).
Dreaming is another phenomenon which has not been extensively assessed during daytime naps. Emotions associated with dream perception are thought to be more intense in people with narcolepsy compared to healthy controls. This effect is even more pronounced during daytime naps and is associated with sleep-onset REM periods (SOREMPs (Fosse et al., 2002)).
We hypothesize that sleep state misperception is common in sleep disorders with EDS. Since we consider sleep state misperception in these disorders to be clinically most important during the day, we assessed sleep state perception and factors influencing it, including the occurrence of REM sleep, during the
Daytime sleep state misperception
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