Assessing sleep-wake survival dynamics in relation to sleep quality in a placebo-controlled pharmacological intervention study with people with insomnia and healthy controls

Lieke W A Hermans*, Marta Regis, Pedro Fonseca, Sebastiaan Overeem, Tim R M Leufkens, Annemiek Vermeeren, Merel M van Gilst

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


RATIONALE: The mechanisms underlying impaired sleep quality in insomnia are not fully known, but an important role for sleep fragmentation has been proposed.

OBJECTIVES: The aim of this study is to explore potential mechanisms of sleep fragmentation influencing alterations of perceived sleep quality.

METHODS: We analyzed polysomnography (PSG) recordings from a double-blind crossover study with zopiclone 7.5 mg and placebo, in elderly participants with insomnia complaints and age-matched healthy controls. We compared survival dynamics of sleep and wake across group and treatment. Subsequently, we used a previously proposed model to estimate the amount of sleep onset latency (SOL) misperception from PSG-defined sleep fragmentation. Self-reported and model-estimated amount of SOL misperception were compared across group and treatment, as well as model prediction errors.

RESULTS: In the zopiclone night, the average segment length of NREM sleep was increased (group F = 1.16, p = 0.32; treatment F = 8.89, p < 0.01; group x treatment F = 0.44, p = 0.65), while the segment length of wake was decreased (group F = 1.48, p = 0.23; treatment F = 11.49, p < 0.01; group x treatment F = 0.36, p = 0.70). The self-reported and model-estimated amount of SOL misperception were lower during the zopiclone night (self-reported group F = 6.08, p < 0.01, treatment F = 10.8, p < 0.01, group x treatment F = 2.49, p = 0.09; model-estimated F = 1.70, p = 0.19, treatment F = 16.1, p < 0.001, group x treatment F = 0.60, p = 0.55). The prediction error was not altered (group F = 1.62, p = 0.20; treatment F = 0.20, p = 0.65; group x treatment F = 1.01, p = 0.37).

CONCLUSIONS: Impaired subjective sleep quality is associated with decreased NREM stability, together with increased stability of wake. Furthermore, we conclude that zopiclone-induced changes in SOL misperception can be largely attributed to predictable changes of sleep architecture.

Original languageEnglish
Pages (from-to)83-94
Number of pages12
Issue number1
Early online date17 Sept 2020
Publication statusPublished - Jan 2021


  • Insomnia
  • Sleep state misperception
  • Sleep onset latency
  • Sleep fragmentation
  • Zopiclone
  • EEG
  • NREM

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