Insomnia combined with sleep apnea associated with worse memory in older women

Older women with both insomnia and sleep apnoea show worse verbal memory than those with sleep apnoea alone, a new study has found.

The research revealed that older adults with comorbid insomnia and sleep apnoea, often referred to as COMISA, demonstrated worse memory performance than those with sleep apnoea alone. Sleep apnoea is a condition where breathing repeatedly stops and starts during sleep.

However, when analysed by sex, the association was only significant in women, not men.

The study, conducted by researchers at UC San Diego School of Medicine, involved 110 older adults aged 65 to 83 diagnosed with obstructive sleep apnoea.

Participants completed an overnight sleep study and cognitive testing. COMISA was present in 37 per cent of participants.

Lead author Breanna Holloway, a postdoctoral researcher at UC San Diego School of Medicine, said: “We expected that having both insomnia and sleep apnoea would worsen memory for everyone, but only older women showed this vulnerability.

“That was striking, especially because women typically outperform men on verbal memory tasks.

“The fact that COMISA seemed to offset that advantage hints at a hidden sleep-related pathway to cognitive decline in women.

“Prior studies have shown increased incidence of Alzheimer’s disease in women with untreated sleep apnoea.”

The researchers suggest sex differences in sleep architecture may explain the vulnerability observed in women.

Post hoc analyses revealed that women with COMISA had reduced rapid eye movement (REM) sleep, the stage associated with dreaming and memory consolidation, and more slow wave (deep) sleep compared with men.

Holloway said: “These results point to an overlooked risk in women with both insomnia and sleep apnoea.”

“Because women are more likely to have insomnia and often go undiagnosed for sleep apnoea, recognising and treating COMISA early could help protect memory and reduce dementia risk.”

The researchers noted that the findings support sex-specific screening and treatment strategies.