Nightmare disorder shows reduced slow oscillation-dominant spindle coupling in NREM sleep
I. Papp, Zoran Cvetković, Nazanin Biabani, Jan Rosenzweig, Camilla Speicher, Alessio Delogu, Alexander D. Nesbitt, Panagis Drakatos, Ines R. Violante, Dijana Vilić, Clive Ballard, David O’Regan, Peter J. Goadsby, Ivana Rosenzweig
npj Biological Timing and Sleep June 22, 2026 DOI: 10.1038/s44323-026-00094-0 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Retrospective case-control study Peer reviewed |
|---|---|
| Sample size | 58 |
| Population | Adults with nightmare disorder and controls |
| Topics | Dreaming |
| Keywords | Polysomnography Eye movement Sleep system call Sleep stages Arousal K-complex Audiology Coupling piping Anesthesia Slow-wave sleep Sleep onset Sleep disorder Sleep spindle |
| Key findings | Nightmare disorder showed reduced frontal slow-oscillation–spindle coupling and lower K-complex density, indicating altered NREM sleep microarchitecture. |
Abstract
Abstract Nightmare disorder is historically conceptualised as a rapid eye movement (REM) sleep parasomnia, but evidence also points to altered non-rapid eye movement (NREM) sleep physiology. Here, in a retrospective case-control study, we analysed overnight polysomnography from 26 adults with nightmare disorder and 32 controls using a harmonised event-based EEG pipeline. Nightmare disorder showed reduced frontal slow-oscillation–spindle coupling, whereas delta–spindle coupling was preserved, yielding lower coupling dominance than in controls (0.137 ± 0.083 versus 0.238 ± 0.096; p = 6.8 × 10 −5 ). Stage-adjusted K-complex density across the first 6 h from sleep onset was also lower in nightmare disorder (0.463 ± 0.345 versus 0.723 ± 0.475 events per minute of available N2/N3 sleep; p = 0.019), whereas peak-timing differences were not robust. These findings suggest altered NREM sleep microarchitecture in nightmare disorder rather than a phenotype confined to REM sleep, and warrant prospective confirmation in harmonised, clinically phenotyped cohorts.
Comparable studies
Other observational and cohort studies on dreaming, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Lucid Dreaming: a State of Consciousness with Features of Both Waking and Non-Lucid Dreaming Student volunteers trained to become lucid and signal lucidity with horizontal eye... | 2009 | Observational study | n = 6 |
| Nightmare Prevalence, Nightmare Distress, and Self-Reported Psychological Disturbance Young adults with a mean age of 20 years | 2002 | Prospective observational study | n = 116 |
| Long-term effects of extreme situational stress on sleep and dreaming Survivors of traumatic events who complained of sleep disturbances, compared with... | 1987 | Case-control study | n = 11 |
| The relationship of nightmare frequency and nightmare distress to well‐being Adults who reported dreams | 2004 | Observational cohort | n = 147 |
| Dreaming in NREM Sleep: A High-Density EEG Study of Slow Waves and Spindles Healthy human subjects | 2018 | Observational cohort | n = 14 |
Citations in the library
Cites 8
- Aetiology and treatment of nightmare disorder: State of the art and future perspectives Journal of Sleep Research January 29, 2019
- Unaltered EEG spectral power and functional connectivity in REM microstates in frequent nightmare recallers: are nightmares really a REM parasomnia? Sleep Medicine November 1, 2020
- Cortical hyperarousal in NREM sleep normalizes from pre- to post- REM periods in individuals with frequent nightmares. Sleep January 13, 2020
- Sleep spindles are altered in early- but not late-onset nightmare recallers. Sleep Medicine December 1, 2018
- Sleep spindle and psychopathology characteristics of frequent nightmare recallers. Sleep Medicine October 1, 2018
and 3 more in the library