Obstructive Sleep Apnea, CPAP Devices and Hearing Loss

 

by Neil Bauman, Ph.D.

February 11, 2017

 

A man wrote,

I have sleep apnea and I use a CPAP machine every night. When I searched the Internet using Google to find out whether there is any link between sleep apnea and sensorineural hearing loss, I found many articles suggesting a link. I would like to hear your opinion on sleep apnea and hearing loss. What’s the recovery chance if lack of blood flow has caused the sensorineural hearing loss in my case. (That’s the case for many sleep apnea patients.)

Obstructive sleep apnea (OSA) is a growing problem, affecting millions of people in the United States. Some form of obstructive sleep apnea affects approximately 17% of the adult population. Throughout the years, this number has been increasing in tandem with the increasing prevalence of obesity. (1) If you have obstructive sleep apnea, chances are, you’re likely to have some sort of an ear problem whether it arises directly from your ears or not. (2)

So far, studies have shown there is an association between sleep apnea and hearing loss. However, since these studies only collected data at a single point in time, it has been impossible to know which came first—the sleep apnea or the hearing loss. (3) Thus, it’s hard to say for sure whether sleep apnea causes hearing loss or whether both arise from the same underlying cause.

For example, obesity and snoring are two common factors causing sleep apnea. Both of these factors could also cause hearing loss by themselves whether you had sleep apnea or not. You could also wonder whether your hearing loss is due mostly to blood vessel damage from arteriosclerosis, or whether it is due to vibratory damage due to snoring, or even something else (3) such as using a CPAP machine to treat your sleep apnea? In this latter case, is it the sleep apnea itself, or is it your CPAP device that resulted in your hearing loss?

As you can see, there are a number of factors that may be involved in any resulting hearing loss.

Here is a quick review of obstructive sleep apnea to refresh your memory. If you have obstructive sleep apnea, when you sleep your breathing tends to be very slow and shallow (hypopnea), you snore and from time to time you stop breathing (apnea).

You get obstructive sleep apnea when part of your airway closes off while you are trying to inhale during your sleep. This more often occurs if your airway is slightly narrower than normal, or if you are obese.

Note: studies have revealed that hearing loss is more severe in people that have higher body mass indices. (4) Therefore, losing weight is one of the best ways to help get your sleep apnea under control.

If you are overweight, and if you have a lot of excess fat in your neck, this extra fatty tissue tends to narrow your airway as well. This results in a higher risk of developing obstructive sleep apnea. (5)

When you begin to inhale, your lungs expand. This lowers the air pressure inside your airway and air rushes in to fill this partial vacuum. However, if the muscles that keep your airway open are not working hard enough, your airway may narrow or may collapse. This stops any air flowing into your lungs. (5)

The reason obstructive sleep apnea occurs while you are sleeping is because the muscles in your neck that keep your airway open are not as active then. (5)

Furthermore, congestion in your nose and sinuses can make an airway collapse even more likely because the extra effort you need to put forth to inhale will lower the pressure in your airway even more—thus sucking your airway shut. (5)

You can make things worse for yourself if you drink alcohol or take tranquilizers in the evening because these cause your neck muscles to relax even more than normally. (5)

Note that such drugs also lower the “respiratory drive” in your nervous system. (5) The result is that your breathing becomes slower and more shallow (hypopnea).

People with obstructive sleep apnea almost always are heavy snorers. This is because the same narrowing of the airway that causes snoring can also cause obstructive sleep apnea. In fact, snoring may actually be a factor n obstructive sleep apnea. This is because the vibration of your throat tissues can cause them to swell” (5) and this partially closes your airway.

Since sleep apnea is characterized by your airway closing while you sleep, the result is that your blood oxygen levels drop each time this happens, In extreme cases, this may occur as many as 400 to 500 times a night.

Most of the complications associated with sleep apnea, which include high blood pressure, heart problems, strokes and diabetes, are thought to result from these frequent oxygen fluctuations during the night. (6)

Obstructive sleep apnea is often treated with a mask and breathing device, called a continuous positive airway pressure (CPAP) device. Even so, one of the most effective treatments is simply to lose weight. (6)

Did you notice that the above references did not even mention hearing loss and other ear problems? This shows how much importance the medical community gives to our ears. Thus, few people realize that obstructive sleep apnea can permanently damage their precious hearing. As a result, they (and their doctors) don’t take the steps necessary to help prevent this from occurring.

Now, let’s look at how obstructive sleep apnea can affect your ears.

Conductive Hearing Loss

Both obstructive sleep apnea and the use of CPAP devices can cause inflammation in your air passages. Thus, if you have any degree of inflammation in your nose, then additional swelling may prevent proper equalization of the air pressure between your middle ears and the outside air. (2) If the pressure is higher in your middle ear, your eardrum will bulge out. This reduces the contact it has with the malleus (hammer bone) in your middle ear. Your ear will feel “full” and speech will sound muffled. The result will be some degree of a temporary conductive hearing loss until the air pressure equalizes and your hearing returns to normal again.

If you have sleep apnea, due to the additional inflammation that’s created, a simple ear or sinus infection can linger for weeks, and sometimes even months. Any such additional inflammation in your nose or throat causes swelling which can aggravate your condition. (2) As long as this inflammation persists, you may have pressure differential problems and the consequent conductive hearing loss.

Sensorineural Hearing Loss

There are several ways that obstructive sleep apnea can damage your ears and result in sensorineural hearing loss.

Reduced Blood Flow

Obstructive sleep apnea can narrow your blood vessels. This is because sleep apnea increases your body’s levels of inflammatory proteins (3) that results in your arteries becoming inflamed and increases the build-up of plaque on your artery walls. (6). In short, this inflammation increases your risk of arteriosclerosis. (3) One result of narrowed arteries is reduced blood flow to your inner ears. In turn, reduced blood-flow results in reduced levels of oxygen getting to your inner ears.

Furthermore, obstructive sleep apnea reduces the amount of oxygen in your blood because your lungs don’t receive oxygen when your airway is blocked. This just compounds the lack of oxygen to your ears due to the narrowing of your arteries.

The result of this reduced blood flow from narrowed arteries and low blood oxygen levels is that your hair cells (and other structures) in your inner ears can’t function properly. This can result in a temporary sensorineural hearing loss. As long as the hair cells are “sick” you have hope that your hearing will recover once your ears get adequate supplies of oxygen. However, if some of your hair cells ultimately die, that temporary loss turns into a permanent hearing loss.

What are the chances of getting a permanent hearing loss from your sleep apnea?  There is no way to know on an individual basis, but on the average, having sleep apnea increases your chances of a permanent hearing loss by about 38%. (See the final section for more information.)

Sudden Hearing Loss

Sudden hearing loss seems to be associated with obstructive sleep apnea. For example, researchers found that people who had suffered sudden deafness were slightly more likely to have a previous diagnosis of sleep apnea than a comparison group without hearing loss. The absolute difference was small, but significant, at 0.5%. (6)

“When the researchers took into account health and lifestyle factors that may be related to both sleep problems and hearing loss—such as obesity and heart disease—they found that men with sudden deafness were 48% more likely to have a previous sleep apnea diagnosis than men without hearing loss.” (6)

It is likely that if you are obese, you have clogged arteries. Thus you would be more likely to have a mini-stroke in one of your ears. This is where a small piece of plaque breaks off from a partially clogged artery and blocks one of the tiny arteries carrying blood (and oxygen) to your inner ear. The result? Sudden hearing loss as a result of little or no oxygen reaching the hair cells in that inner ear. This can result in temporary hearing loss if the blockage clears and blood flow returns to normal before the hair cells die, or it may result in permanent hearing loss if any hair cells die.

Snoring

“Snoring occurs when the soft palate, uvula, tongue, tonsils, and/or muscles in the back of the throat rub against each other and generate a vibrating sound during sleep.” (7)

In a number of cases, snoring is a symptom of obstructive sleep apnea. If you have obstructive sleep apnea, you almost certainly are a heavy snorer. This is because the same narrowing of the airway that causes snoring can also cause obstructive sleep apnea. In addition, snoring may actually contribute to obstructive sleep apnea because the vibration of your throat tissues, which occurs when you are snoring, can cause the tissues to swell and thus further constrict your airway. (7)

Since snoring is closely associated with obstructive sleep apnea, it stands to reason that loud snoring might also contribute to permanent sensorineural hearing loss in people with sleep apnea.

The question is, “Can hearing loss result from the trauma caused by loud snoring? (4) The answer is a qualified yes. One study revealed that the noise from snoring could be another factor in hearing loss in people with sleep apnea.

Average levels of snoring are around 40 dB—about the same level of noise as you would hear in a library (think constant whispering and quiet chattering). (2) This is softer than a person normally talks—around 55 – 60 dB—so that is nothing to worry about in terms of damaging your hearing. Some people snore louder—70 dB and higher.

Any sounds up to 70 dB are considered to be safe, no matter how long your ears are exposed to them. Therefore, if you, or your spouse, snore at levels up to 70 dB, there should not be any damage to your hearing, although you may be annoyed by the racket.

It’s in those people whose snoring sound levels are above 70 dB, that you have to begin to take notice. The Occupational Health and Safety Administration (OHSA) in the USA has regulations for the level of noise exposure in the workplace. These regulations begin at 85 dB and limit noise exposure at that level to a maximum of 8 hours. Above that level, you are required either to wear ear protectors or reduce the time you expose your ears to these louder sounds. Here’s how it works. For every 3 dB increase above 85 dB, you need to cut in half the length of time you expose your ears to that level of sound.

Thus, for a sound at 88 dB you’d shorten your maximum exposure time from 8 hours to 4 hours; for a level of 91 dB, you’d only expose your ears for a maximum or 2 hours, and so on.

This means that if you are a loud snorer like Melvyn—recorded snoring at a whopping 92 dB, the safe time exposure for both yourself and your spouse would be just 1½ hours without ear protection according to the OHSA regulations (which don’t apply to private homes, but would apply if you fell asleep at work)!

And if you are like Jenny Chapman, who snores at an ear-shattering 111.6 dB—that’s louder than a jackhammer or a low-flying jet (8)—your safe exposure time would be a minuscule 1 minute without ear protection.

Obviously higher levels of snoring exceed the OSHA safety standards and thus can cause hearing loss to both you and your spouse. Some spouses of noisy snorers have been shown to have a substantial hearing loss in the ear that faces their snoring, partner. (9)

It is likely that snoring precedes obstructive sleep apnea and is one sign that you may be developing obstructive sleep apnea. Treating the fundamental cause of the snoring may head off the impending obstructive sleep apnea. So also would treating obstructive sleep apnea with a CPAP machine that is correctly set to stop your snoring.

CPAP Devices

Because the incidence of obstructive sleep apnea has been steadily increasing, there has been a corresponding ever-increasing rise in the use of continuous positive airway pressure (CPAP) devices. (1)

CPAP devices prevent the collapse of your upper airway by providing continuous positive pressure to the back of your mouth, nose and throat areas. The pressure required varies from person to person. Doctors carefully determine the minimum pressure you need (the fancy medical term is “titration”) to prevent snoring, very slow breathing, and episodes of stopping breathing. (1)

The minimum starting CPAP pressure should be 4 cm H2O in adults and should be set to the lowest possible pressure at which sleep apnea and associated events are eliminated. The maximum pressure should not exceed 20 cm of H2O. (1)

When set properly, CPAP devices help you breathe better so more oxygenated blood flows to your head, and thus your inner ears get more oxygen and function better. That’s the good news.

However, there are a couple of adverse effects from using CPAP devices of which you should be aware.

First, the constant flow of air in your mouth and nose can dry out your mouth and nose and also cause congestion. (1) When congestion occurs, your airway is partially blocked and thus you have to work harder to breathe. Even worse, as we saw previously, when you breathe harder, the air moves faster as you inhale. This lowers the pressure in your airway even more, thus sucking your airway shut. (5)

Second, if you adjust the airflow on your CPAP machine yourself to increase the air flow so you can breathe easier, you may cause barotrauma to your ears. Barotrauma is when you get damaging levels of air pressure in your middle ears. When this occurs, bad things can happen. (1)

Barotrauma in your ears results from too great a pressure differential between the air pressure in your middle ears and the outside air pressure. While middle ear barotrauma can cause enough inflammation within the middle ear to result in conductive hearing loss, it may also be transmitted to the inner ear, causing a sensorineural hearing loss.

This inner-ear barotrauma may result when your Eustachian tubes open and air rushes in. This brisk inward movement of air pushes on the oval window just like a very loud sound would and with the same results. It may be so violent that it ruptures the thin oval-window membrane and permits an inner ear fluid (perilymph) to leak out (what doctors call a perilymph fistula). This results in a sudden sensorineural hearing loss. (1)

This can and does happen. Here’s one such story. A middle-aged, obese man went to his doctor for help with his sleep apnea. His doctor determined that the correct CPAP pressure to prevent snoring and sleep apnea episodes was 15 cm H2O.

This man went home and as the weeks passed, his weight increased. To compensate for his weight gain, he kept turning the pressure up on his CPAP machine a bit at a time. Some weeks later this man came back to his doctor complaining of sudden hearing loss and a feeling of fullness in his ear. He also had pain in his right ear and had heard a popping sound. This had begun suddenly after he had turned up the pressure on his CPAP machine to maximum.

Upon examining him, his doctor discovered that his right middle ear was filled with fluid. His audiogram revealed he had a significant mixed hearing loss in his right ear. The conductive component was caused by the fluid in his middle ear. The sensorineural component was the result of a perilymph fistula. (1) Essentially, this man had “blown out” his inner ear with excessive pressure from his CPAP machine.

Note: when you are using a CPAP device, typically there is an increase in middle-ear pressure. This occurs when you swallow and momentarily open your Eustachian tubes. Rather than equalizing the air pressure in your middle ear with the outside air pressure, when using a CPAP machine, this results in increased middle ear pressure. This increase in pressure is directly proportional to the pressure delivered by your CPAP machine. (1) Sometimes this can lead to problems.

For example, a man ruptured both of his eardrums from the CPAP pressure. In his case, his doctor figured that he had coughed against the CPAP. This cough, with its own high pressure and his opened Eustachian tubes allowed both the cough pressure and the high pressure of the CPAP machine to rush into his middle ears. In his case, it blew out his middle ears causing him to have a conductive hearing loss! (1)

This is why you always want to use the lowest CPAP pressure that will control your obstructive sleep apnea.

How Bad Is the Risk of Hearing Loss from Sleep Apnea?

Obstructive sleep apnea affects a lot of people; so does hearing loss. Some form of obstructive sleep apnea affects approximately 17% of the adult population. (1) Hearing loss affects around 25% of the population in the USA. Thus is should be no surprise that a lot of people have both sleep apnea and hearing loss.

Unfortunately, people with sleep apnea have a higher incidence of hearing loss than is warranted by their numbers. This seems to indicate that sleep apnea causes hearing loss in numbers of people.

For example, in one study, based on 13,967 subjects of which 53% were women and the average age was 41, about 10% of the study volunteers had moderate sleep apnea, while 29% had some form of hearing loss. (10) Note: moderate sleep apnea was defined as an apnea/hypopnea index greater than 15—i.e. 15 or more such events per hour.

In this study, there was evidence for a dose-response relationship between the increasing apnea/hypopnea index and any hearing impairment. (3) Findings showed that “sleep apnea was independently associated with a 31% increase in high-frequency hearing impairment, a 90% increase in low-frequency hearing impairment and a 38% increase in both.” (4)

People with moderate sleep apnea had a 22% increased risk of hearing impairment, while severe sleep apnea was associated with a 46% increased risk. The association between sleep apnea and hearing loss was significant and independent of symptoms such as snoring, exposure to external noise and conductive hearing loss. (3)

The bottom line is simply this—if you want to avoid hearing loss from obstructive sleep apnea, you need to get your weight down to a normal level, and do all the things that can help you get your obstructive sleep apnea under control. Better yet, do these right things now—and hopefully you’ll not have to worry about even getting obstructive sleep apnea!

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(1) McCormick, Justin, et. al. Otic Barotrauma Resulting from Continuous Positive Airway Pressure: Case Report and Literature Review.

(2) The Biggest Ear Problems for Sleep Apnea Sufferers. 2017.

(3) Hanson, Mark. 2016. Sleep Apnea and Hearing Loss.

(4) Big New Study Shows Sleep Apnea Tied to Hearing Loss. 2014.

(5) Sleep Apnea. 2017. The Free Medical Dictionary.

(6) Pittman, Genevra. 2012. Study Links Sleep Apnea and Sudden Deafness.

(7) Snoring. 2017. The Free Medical Dictionary.

(8) Meet the Grandmother Who Snores at 111 Decibels…Louder Than a Jet Plane. 2009.

(9) McCaffrey, Lindsey. 2015. 5 Things You Should Know if Your Partner Snores Like a Jackhammer or Has Sleep Apnea, Because a Didgeridoo May Be the Answer to All Your Bedtime Problems.

(10) Vasta, Chris. 2014. Is Sleep Apnea Linked to Hearing Loss?