The neurophysiologic landscape of the sleep onset: a systematic review

Nazanin Aghajan Biabani, Adam Birdseye, Sean Higgins, Alessio Delogu, Jan Rosenzweig, Zoran Cvetkovic, Alexander Nesbitt, Panagis Drakatos, Joerg Steier, Veena Kumari, David O’Regan, Ivana Rosenzweig

Research output: Contribution to journalReview articlepeer-review


Background: The sleep onset process is an ill-defined complex process of transition from wakefulness to sleep, characterized by progressive modifications at the subjective, behavioural, cognitive, and physiological levels. To this date, there is no international consensus which could aid a principled characterisation of this process for clinical research purposes. The current review aims to systemise the current knowledge about the underlying mechanisms of the natural heterogeneity of this process.
Methods: In this systematic review, studies investigating the process of the sleep onset from 1970 to 2022 were identified using electronic database searches of PsychINFO, MEDLINE, and Embase.
Results: A total of 139 studies were included; 110 studies in healthy participants and 29 studies in participants with sleep disorders. Overall, there is a limited consensus across a body of research about what distinct biomarkers of the sleep onset constitute. Only sparse data exists on the physiology, neurophysiology
and behavioural mechanisms of the sleep onset, with majority of studies concentrating on the non-rapid eye movement stage 2 (NREM 2) as a potentially better defined and a more reliable time point that separates
sleep from the wake, on the sleep wake continuum.
Conclusions: The neurophysiologic landscape of sleep onset bears a complex pattern associated with a multitude of behavioural and physiological markers and remains poorly understood. The methodological variation and a heterogenous definition of the wake-sleep transition in various studies to
date is understandable, given that sleep onset is a process that has fluctuating and ill-defined boundaries. Nonetheless, the principled characterisation of the sleep onset process is needed which will allow for a greater conceptualisation of the mechanisms underlying this process, further influencing the efficacy of
current treatments for sleep disorders
Original languageEnglish
Pages (from-to)4530-4543
Number of pages14
JournalJournal of Thoracic Disease
Issue number8
Early online date14 Aug 2023
Publication statusPublished - 31 Aug 2023


Dive into the research topics of 'The neurophysiologic landscape of the sleep onset: a systematic review'. Together they form a unique fingerprint.

Cite this