Sleep apnea, responsible for cognitive disorders - A la une

2023-05-03 14:36:55

03 May 2023

According to a recent study, obstructive sleep apnea-hypopnea syndrome (OSAS) causes cognitive disorders such as reduced alertness and immediate visual memory.

We knew that sleep apnea could be a cardiovascular risk factor. According to a recent study published in the journal Frontiers in Sleep, sleep apnea or obstructive sleep apnea-hypopnea syndrome (OSAS) can also be the cause of a premature decline in cognitive abilities. As a reminder, “sleep apnea syndrome is manifested by the repeated closure of the airway at the level of the pharynx, for 10 to 30 seconds or sometimes more, at a rate of at least five events per hour of sleep”explains Inserm.

A study conducted on patients without comorbidity

The British, Australian and German researchers studied a group of 27 men, aged 35 to 70, affected by moderate to severe sleep apnea. None of these men suffered from any comorbidity or addiction to alcohol or tobacco.

Results ? Decreased alertness, executive functioning, visual short-term memory, emotion recognition, and social cognition were observed in participants. The same capacities were impacted whether the sleep apnea was moderate or severe. However, the more severe the OSAHS, the more pronounced the cognitive disorders.

These disorders were previously associated with the most common comorbidities of OSAS – hypertension, cardiovascular and metabolic diseases and type 2 diabetes. According to the study authors, sleep apnea without comorbidity may thus be solely responsible for disorders cognition in patients.

A difficult mechanism to explain

Without being able to precisely explain the mechanism, the researchers believe that these manifestations are due to the decrease in oxygen and the increase in carbon dioxide in the blood, intermittently. Changes in blood flow to the brain, fragmented sleep and neuroinflammation found in people with sleep apnea could also be to blame. “This complex interaction is still poorly understood, but it is likely to lead to widespread neuroanatomical and structural changes in the brain and associated cognitive and emotional functional deficits”explains Dr. Ivana Rosenzweig, neuropsychiatrist at the Center for Sleep and the Brain of the King’s Collegein London.

The study recalls that sleep apnea is largely under-diagnosed. 15 to 30% of men and 10 to 15% of women suffer from it worldwide. With nearly a billion people affected, 80% of them would be affected without knowing it. In France, according to Inserm, 7.9% of people aged 20 to 44, 19.7% of people aged 45-64 and 30.5% of people over 65 are affected. Figures, specifies the Institute, which would be below reality.

Source : Frontiers in sleep, Inserm
Written by : Dorothée Duchemin – Edited by Emmanuel Ducreuzet