Sleep Apnea and Cognitive Impairment

Convincing a patient to undergo a sleep analysis for obstructive sleep apnea is a difficult task. During our history taking session, we ask about excessive snoring, periods of not breathing while asleep, daytime sleepiness and we look at the patient’s body habitus, weight and height. Often, the patient’s spouse or partner has complained about their snoring keeping them up. Most of the time, when I ask about this the response is, “Why go for an evaluation if I am not going to wear that mask anyway?  I have a friend who has a CPAP mask and I am just not going to do that.”

Obstructive sleep apnea and periods of apnea (not breathing) results in the lung blood vessel blood pressure rising.  We call it pulmonary hypertension.  It is different from systemic arterial essential hypertension in that traditional blood pressure medicines do not lower the pulmonary pressures.

If you examine our heart and lung anatomy you realize that the very non-muscular right side of the heart, primarily the right ventricle, pumps blood a short distance to the lungs to exchange gases and removing wasteful gases in exchange for oxygen. That oxygen rich blood returns to the left side of the heart where the very muscular left ventricle pumps it out to the body.

When the body’s systemic blood pressure rises the left side of the heart has to work harder. The muscular left ventricle is much more suited for that task than the right ventricle is suited to pump against pulmonary vessel hypertension.  The result is the right heart fails much sooner than the left side and the treatment options and medications are far less successful.  This explanation to patients is often received, digested and dismissed as hypothetical and down the road.

This week the American Academy of Neurology received a presentation by a group at the Mayo Clinic in Rochester that showed that patients with untreated sleep apnea produced an increased amount of tau protein deposition in the brain. Tau protein deposition is associated with Alzheimer’s disease.  The researchers, led by Diego Z. Carvalho, MD, are not sure if more Tau protein accumulates in brains of people with untreated sleep apnea or if Tau protein accumulation actually leads to sleep apnea?  That research is ongoing.

The lesson is that sleep apnea is something that needs to be diagnosed and treated. I am a fan of referring patients’ to sleep evaluation centers where that is the primary disease state reviewed.

While sleep apnea is one of the abnormalities evaluated, there are many other disorders of sleep that can be recognized and treated to improve patient sleep. At home sleep monitors are available as well but may be limited in diagnosing sleep apnea alone.

If you are determined to have obstructive sleep apnea then treatment choices include weight loss, laser treatment of the uvula, dental appliances to open up your airways, adjustments to your sleep position and many types of facial and nasal CPAP devices.

Most of my patients who try a CPAP mask require 8-12 weeks to adjust to it. Once adjusted to it, their quality of sleep is so good that I rarely have to convince them to keep using it.

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Electrical Stimulation May Improve Sleep Apnea

Sleep Apnea v2Patrick Strollo Jr., MD of the University of Pittsburgh Medical Center presented preliminary data on the use of a surgically implanted neurostimulator to improve sleep apnea symptoms. The device was implanted to stimulate the hypoglossal nerve. The participants in the study were 124 patients who could not tolerate the CPAP mask treatment or who were never before treated. After implantation they were treated and followed for one year. The participants were mostly men (83%) in their mid-fifties (mean age 54.5 years old), Caucasian and overweight (mean BMI 28.4 kg/m2). Thirty eight percent of the participants had hypertension, 9% were diabetic, and 5% had COPD. Interestingly, 18% had undergone previous surgery on the uvula called uvulopalatopharyngoplasty which was felt to be an effective alternative to wearing a CPAP mask for sleep.

At 12 months all the parameters to assess the effects of sleep apnea had improved dramatically. Interestingly enough, some of the study participants were allowed to continue treatment while others were randomized to stop the neurostimulation. Those who stopped the treatment were followed and their scores regressed.

Like all treatments there were some adverse effects such as tongue pain and mild to moderate infection in 1%.

This is very preliminary data. The study must be presented to a peer review journal, evaluated and published before this treatment becomes acceptable. We recognize sleep apnea as a dangerous disease that leads to pulmonary hypertension and right heart failure if not treated. CPAP masks work well but are cumbersome, awkward and difficult to travel with. The epidemic of sleep apnea is being fueled by a worldwide epidemic of obesity. The current preliminary work at the University of Pittsburgh holds out hope for a future solution that may be easier to live with.