Sex and insomnia shape NREM sleep oscillations beyond age in 222 adults
In one polysomnography night, age, chronic insomnia and sex each contributed separately to NREM sleep oscillations in 222 adults aged 18–82; insomnia mainly lowered spindle and slow-oscillation density, while sex accounted for slow-wave activity differences. [1]
Automatic summary · not editorially reviewed
The key findings
One polysomnography night was analyzed in 222 adults aged 18–82, including 119 with chronic insomnia and 103 healthy sleepers. [1]
Age, insomnia and sex each contributed uniquely to NREM oscillatory activity; insomnia primarily reduced spindle and slow oscillation density. [1]
Female participants with insomnia reported the highest insomnia severity and had lower sigma power than males with insomnia. [1]
The source at a glance
- Study type / format
- Abstract of a polysomnography study comparing adults with chronic insomnia and healthy sleepers
- Population / context
- 222 adults aged 18–82: 119 with chronic insomnia disorder and 103 healthy sleepers.
- Summary based on
- Study abstract
- Original publication
- October 1, 2026
222 adults, one night, age as covariate
After a habituation night, one night of sleep measured with polysomnography was analyzed in 222 adults aged 18–82. This included 119 people with chronic insomnia disorder (71% female) and 103 healthy sleepers (61% female). During NREM sleep, the researchers derived spindle density, slow oscillation density, relative sigma power and slow-wave activity. They examined age, group, sex and group-by-sex interactions, with age as a covariate.
Supporting source [1]
Insomnia lowered spindle and slow-oscillation density
Age, insomnia and sex each contributed uniquely to NREM oscillatory activity. Chronic insomnia primarily reduced spindle and slow oscillation density. Sex accounted for differences in slow-wave activity, which was higher in females overall; however, sex differences were not significant within the insomnia or healthy-sleeper groups. Female participants with insomnia reported the highest insomnia severity and had lower sigma power than males with insomnia. Spindle and slow oscillation density deficits also appeared in female insomnia versus female healthy sleepers, and in male insomnia versus male healthy sleepers.
Supporting source [1]
Abstract-only scope of the oscillation findings
The authors conclude that reduced sigma power in females with chronic insomnia relative to males with insomnia, plus lower spindle and slow oscillation density than female healthy sleepers, may contribute to greater insomnia severity in females. These are associations from one analyzed night, not causal proof. Only the abstract was reviewed; the full text was not reviewed, so details such as recruitment, medication and analysis choices are not assessed here.
Supporting source [1]
How to interpret this
Abstract only; the full text was not reviewed. Findings come from one analyzed night and are associations, not causal proof.
Based on the study abstract; the full paper, tables and supplementary data were not reviewed.
Source & supporting passages
Walsh NA, Perrault AA, Cross NE, Maltezos A, Phillips EM, Barbaux L, Weiner OM, Dyment C, Borgetto F, Gouin JP, Dang-Vu TT. · europepmc.org · October 1, 2026