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Obstructive sleep apnea common in individuals with dementia

March 1, 2021


In a new study, Sunnybrook researchers have found that a high rate of obstructive sleep apnea occurs in patients with thinking and memory problems, including dementia.

Obstructive sleep apnea happens when an individual’s breathing stops briefly and is interrupted throughout the night while sleeping. Sometimes breathing can stop for 10 seconds or longer. This reduced airflow can have lasting impacts on the brain.

Signs and symptoms of obstructive sleep apnea include, but are not limited to, loud snoring, waking up suddenly and gasping or choking, excessive daytime sleepiness, high blood pressure, and even mood changes including irritability and depression.

“This is one of the first studies to highlight the prevalence of sleep apnea and its link with severe cognitive impairment,” says Dr. Mark Boulos, the study’s principal investigator and neurologist at Sunnybrook Health Sciences Centre. “We know that sleep apnea is a risk factor for cognitive impairment and dementia, so the high prevalence of obstructive sleep apnea in patients with thinking and memory issues suggests the potential for patients to be treated and have their cognition stabilized or possibly improved.”

“Our study also demonstrated that obstructive sleep apnea severity is correlated with lower cognition and poorer sleep quality,” says David Colelli, lead author of the study, and research coordinator with the LC Campbell Cognitive Neurology Research Unit at Sunnybrook. “Participants with severe sleep apnea were more likely to have more severe thinking and memory problems.“

The study was recently highlighted by the American Academy of Neurology.

Sixty-seven patients who had cognitive impairment participated in the study. The average age was 73 years old.

“Our study investigated a broad spectrum of cognitive impairment through various tests,” says David. “Participants completed assessments and questionnaires that focused on sleep, cognition and mood. They were also given at-home devices that monitored oxygen levels and breathing patterns to determine if participants had obstructive sleep apnea. The at-home test uses a monitor to track breathing patterns and oxygen levels during sleep.”

Researchers say past studies have shown at-home sleep apnea testing devices have accuracy rates as high as 95 per cent compared to in-laboratory sleep studies.

In the study, 52 per cent of participants were found to have obstructive sleep apnea.

Those with sleep apnea were 60 per cent more likely to score lower on cognitive tests than those who did not have the sleep disorder.

“It is important for individuals with cognitive impairment to be assessed for obstructive sleep apnea and receive treatment,” says Dr. Boulos. “A continuous positive airway pressure (CPAP) machine is commonly used to treat obstructive sleep apnea. The CPAP machine helps keep a person’s airway open and keeps oxygen flowing to the brain.”

Dr. Boulos also notes consistent use of CPAP machine may be a challenge for individuals with cognitive impairment and that it is important for further investigation to determine effective methods to diagnose and more easily manage treatment for the sleep disorder.

Researchers add future research is needed to examine whether treating sleep disorders will help improve outcomes such as cognition and quality of life in patients who have thinking and memory concerns.

The study was funded by an Ontario Graduate Scholarship awarded to study author David R. Colelli and the LC Campbell Cognitive Neurology Research Unit at Sunnybrook Health Sciences Centre in Toronto, Canada. ResMed provided the at-home sleep apnea tests as in-kind support but was not involved in the design of the study.

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