Recently, I saw a patient who had white matter lesions on an MRI of her brain. Neurology considered them an incidental finding, but the patient was struggling with cognitive function. Most concerning to the patient was her inability to recall names and her forgetfulness. This was all being attributed to going through menopause.
On my initial exam of the patient, she had multiple risk factors for obstructive sleep apnea (OSA). The patient had a neck circumference of sixteen inches and in a female, anything over fourteen inches is considered a risk factor for OSA. In addition, there was complete obstruction of the patient’s oropharynx by the tongue or a Class IV Malampatti scoring. An at-home sleep study confirmed that the patient had severe OSA
Health Risks Associated With Obstructive Sleep Apnea
There has been some recent research that has shown an association between obstructive sleep apnea and Alzheimer’s disease. We have known for many years that OSA is a risk factor for both cardiovascular disease and cerebrovascular disease, mostly through metabolic derangements such as diabetes mellitus and hyperlipidemia. OSA can also aggravate hypertension, another risk factor for both cardiovascular and cerebrovascular disease.
Recent studies have shown that obstructive sleep apnea can be linked to Alzheimer’s disease in several different ways. Low oxygen levels that occur during OSA impede the brain’s ability to clear amyloid plaques which is a hallmark of Alzheimer’s. In this patient, oxygen saturations fell to as low as 77%; anything under 88% is considered clinically significant.
Effects of Obstructive Sleep Apnea on Brain Health
There are other effects that OSA can have on brain health that need to be mentioned.
- Intermittent hypoxia can cause stress to brain cells.
- Poor sleep, which is triggered by obstructive sleep apnea causes oxidative stress and inflammation, both of which can damage brain tissue.
- Poor sleep slows down the glymphatic system of the brain.
The glymphatic system is a unique system of the brain that functions very much like the lymphatic system of the body. It helps eliminate waste and toxins from the brain. The most important association with Alzheimer’s is amyloid. The glymphatic system of the brain helps clear toxins such as amyloid during sleep.
Why Treating Sleep Apnea Matters for Cognitive Health as We Age
As life expectancy increases, and we find ourselves living longer with a better quality, sixty is the new forty, they say. What good is it if we don’t have the cognitive ability to enjoy it? If you feel that you’re becoming forgetful or that you can’t do simple math in your head anymore in association with waking up several times a night, please get checked out for sleep apnea, it could make the golden years more memorable.
