New research has discovered that older women who suffer from both sleep apnoea and insomnia have significantly lower verbal memory than men with the same symptoms, raising new worries about the hidden impact of disrupted sleep on women's cognitive health. The study identifies an underappreciated danger for ageing women and proposes that early detection and therapy may help safeguard long-term brain function. 

Sleep apnoea is a condition in which breathing repeatedly stops and starts during sleep because the airway gets obstructed. In contrast, insomnia is defined as continuous trouble sleeping or staying asleep. Researchers refer to the combination of these two circumstances as COMISA. Doctors are already aware that either problem can disrupt sleep, but this new study suggests that the combo may disproportionately affect women's capacity to remember words and language-based knowledge. 

The study found that older persons with COMISA scored worse on verbal memory tests than those with sleep apnoea alone. This effect persisted even after controlling for age, body weight, education level, and the severity of their sleep apnoea. However, when the results were examined by gender, only women demonstrated substantial memory difficulties associated with COMISA. 

"We expected insomnia and sleep apnoea to impair memory in everyone, but only older women demonstrated this sensitivity. That was surprising, especially since women typically outperform men on verbal memory tasks," said main author Breanna Holloway, a postdoctoral researcher at the UC San Diego School of Medicine. "The fact that COMISA appeared to offset that advantage suggests a hidden sleep-related pathway to cognitive decline in women." Previous research has found that women with untreated sleep apnoea had a higher risk of developing Alzheimer's disease." 

The study, published in the most recent issue of the Journal of Clinical Sleep Medicine, included 110 adults aged 65 to 83 who had been diagnosed with obstructive sleep apnoea. Participants completed an overnight sleep study, cognitive tests, and conventional measures of insomnia and verbal memory. COMISA was discovered in 37% of the cohort, indicating that the two sleep disorders overlap relatively frequently. 

To determine why women were more affected, the researchers looked at disparities in sleep patterns. They discovered that women with COMISA had less rapid eye movement (REM) sleep and more slow-wave sleep than men. REM sleep is associated with dreaming and memory processing, whereas slow-wave sleep is the deepest stage of sleep. Losing REM sleep may consequently impair the brain's ability to store new knowledge, explaining the steeper loss found in women. 

"These results point to an overlooked risk in women with both insomnia and sleep apnoea," Holloway told the audience. "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." 

Dr Atul Malhotra, the primary investigator and senior pulmonologist at UC San Diego Health, stated that the findings support sex-specific screening and treatment approaches. He observed that clinicians frequently overlook sleep apnoea in women since their symptoms differ from those in men, resulting in diagnostic delays. 

The study emphasises the importance for healthcare practitioners to pay more attention to sleep issues in older women, especially when amnesia or daytime exhaustion occurs. As the population ages and dementia rates grow, addressing hidden concerns like COMISA could be crucial to enhancing long-term cognitive health.