Obstructive sleep apnoea linked to cognitive decline, raises need for targeted treatment options

Australia: Findings from a recent study published in Sleep Health support the value of sleep spindles as useful cognitive function markers in obstructive sleep apnea (OSA).

The researchers showed that specific sleep spindle metrics were associated with cognitive function, and the severity of obstructive sleep apnea moderated these associations.

Flinders University experts are working on better solutions for sleep apnoea to ward off various health risks, including cognitive decline. Improved solutions for obstructive sleep apnoea (OSA), insomnia and other sleep disorders are being developed by the Flinders Sleep Health experts to reduce the associated negative health effects such as cardiovascular harm, diabetes, anxiety and depression and even long-term cognitive decline.

This study focuses on the heightened risk of cognitive function decline from undiagnosed OSA- particularly in middle-aged men living in the community.

The study recorded the sleep patterns of more than 470 men aged 41-87 years along with their daytime cognitive function for processing speed, visual attention, episodic memory recollection and other markers.

Measuring distinct features of brain electrical activity during non-REM sleep, called ‘sleep spindles’, the study aimed to explore if these features can serve as markers of cognitive function.

“Non-REM sleep includes light stage 1 and 2 sleep, as well as deeper stage 3 sleep which is thought to play an important role in learning and memory,” says Flinders University sleep researcher Dr Jesse Parker.

“Our study found cross-sectional associations between various domains of next-day cognitive function and several sleep spindle metrics during stage 2 and stage 3 of their sleep cycle.

“The presence and severity of OSA was an important factor in this relationship.”

While standard clinical tests for OSA may detect and help to improve this common sleep-related breathing disorder with interventions such as continuous positive airway pressure (CPAP) or specific dental devices, the condition does vary between people depending on gender, age and other factors.

Based on this latest Florey Adelaide Male Ageing Study results, the Flinders Health and Medical Research Institute Sleep Health researchers recommend long-term investigations into sleep spindle phases and OSA to improve future treatments-and to determine whether OSA interventions such as CPAP do improve sleep quality and cognitive function.

Sleep apnoea affects more than 1 billion people globally and if untreated or severe may increase the risk of dementia and Parkinson’s disease, hypertension, cardiovascular disease, anxiety and depression, reduced quality of life, traffic accidents and all-cause mortality, previous research has found. In Australia alone, the economic cost associated with poor sleep including sleep disorders has been estimated at $66 billion a year.

“Poor sleep as a result of OSA, as well as delayed sleep and body clock disruption, may lead to chronic health conditions, including cognitive impairment, poor mental health and cardiovascular disease,” says Associate Professor Andrew Vakulin, senior author on the publication and Flinders Health and Medical Research Institute (FHMRI) Sleep Health researcher.

“Highlighting the need for better treatments, our latest studies not only make more links between sleep disorders and poor health outcomes but also the need for tailored specific treatments for individual cases, including co-occurring conditions such as insomnia and sleep apnoea.

"Along with uncontrolled hypertension, this latest study also clearly links cognitive function to sleep in adult males, possibly made worse by undiagnosed moderate to severe OSA,” says Associate Professor Vakulin.

Reference:

Jesse L. Parker, Sarah L. Appleton, Robert J. Adams, Yohannes Adama Melaku, Angela L. D'Rozario, Gary A. Wittert, Sean A. Martin, Peter G. Catcheside, Bastien Lechat, Alison J. Teare, Barbara Toson, Andrew Vakulin, The association between sleep spindles and cognitive function in middle-aged and older men from a community-based cohort study, Sleep Health, 2023, https://doi.org/10.1016/j.sleh.2023.03.007.