Sleep architecture and rapid eye movement sleep without atonia in post-COVID-19 insomnia

Classical PSG profile of post-COVID-19 insomnia does not differ from non-COVID-related chronic insomnia. However, subtle differences in RWA and sleep integrity suggest that post-COVID-19 insomnia is driven not merely by pandemic-related stress factors but by additional physiological alterations linked to viral central nervous system involvement. Statement of Significance Insomnia is a major symptom in long-COVID, yet objective studies examining its electrophysiological underpinnings are scarce. We present the largest video-polysomnographic investigation comparing post-COVID-19 insomnia with chronic insomnia unrelated to COVID-19. While classical sleep architecture metrics did not significantly differ between post-COVID-19 insomnia and matched pre-pandemic and pandemic-era non-COVID-insomnia patients, our findings reveal subtle but important distinctions. Patients with post-COVID-19 insomnia exhibited significantly increased REM RWA, alongside trends toward altered sleep continuity, including shorter N3 sleep bouts, longer onset to stable REM sleep, and higher nocturnal heart rates. These findings suggest specific central nervous system alterations post-infection that go beyond stress-related pandemic effects and are likely linked to viral central nervous system effects. This highlights the unique neurobiological impact of COVID-19 on sleep regulation, meriting further investigation, even as established insomnia treatments remain applicable.