Hearing Loss and Cognition

by Dr. Jennifer Stinson

According to the Centers for Disease Control, hearing loss affects about 40 million Americans between the ages of 20-69. It may seem dramatic to say, but this puts hearing loss in the category of a national health crisis. In addition to that, there has been a lot of research connecting hearing loss to cognitive decline or dementia. Dementia is a general term for the cognitive deterioration that includes loss of memory and intellectual function. The exact correlation has been difficult to define and for researchers to document as well as whether hearing aid use or amplification can reverse the decline. There is a lot of speculation both in the literature and hearing aid advertisements about this correlation. You may stumble upon some mixed information, so outlined below is a quick and basic explanation so that you can make informed decisions regarding your hearing healthcare. 

In simple terms, cognition is defined as mental processes. When defining cognitive function, you must consider the mental processes of how well you obtain, organize and use knowledge. Hearing is how we often obtain information or knowledge. The connection between what we hear and what we do with what we hear is very important. There are many cognitive processes related to understanding and comprehending speech sounds. When you have hearing loss, you are often unable to hear certain speech sounds. For example, if a person has hearing loss, they may often say, “I can hear you, but I can’t understand what you are saying.” People who have milder hearing loss may communicate ‘just fine’ in quiet situations and not even realize they have a hearing loss. This is due to the brain’s ability to use knowledge of language and the content of the conversation to fill in what letters or words may be missing due to hearing loss. 

Let’s consider the same person with the mild hearing loss and put them in a room with ample background noise. The noise further degrades the speech signal, so it is even harder to use knowledge of language to fill in the missing words or sounds. In this case, the person with the mild hearing loss must work even harder to hear or process what is being said. The person with hearing loss can become frustrated and fatigued during the conversation. 

Now assume this same person, with the hearing loss, is beginning to decline in their cognitive function. The exact cognitive function that was helping to fill in speech sounds and follow a conversation is now declining. Thus, making it even more difficult to mentally process the speech mixed in with the background noise. In this scenario, the person with hearing loss and compounded by reduced cognition function may start to completely remove themselves from conversations that are difficult to hear. This also introduces the connection between hearing loss and depression or social isolation. 

Research conducted by Dr. Frank Lin from Johns Hopkins University identifies this as increased cognitive load. The hearing loss is causing more of a challenge in obtaining information or knowledge. As previously stated, there is no current research stating that wearing hearing aids will prevent further cognitive decline. What we do know is that untreated hearing loss can cause social isolation, depression, and an increased risk of falls. If you have any risk factors that may increase your chances of having a hearing loss at a younger age, you should have your hearing tested. A few common risk factors for hearing loss include a family history of hearing loss, occupational or recreational noise exposure, balance problems, diabetes, and heart disease. If this is you, have conversations with your primary care doctor regarding your hearing care.

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