Health Impacts of Untreated Hearing Loss

Hearing and Cognition, how are the two related?

A common complaint for people who have hearing loss is that they feel they can hear, but there is the perception that everyone is ‘mumbling’ or people are not speaking clearly. The reason for this is that when there is a loss of hearing, high frequencies are typically more impacted than low frequencies. High frequencies provide speech with a lot of its meaning, so when those high frequency sounds are missing, there is a loss in the clarity of speech. The job of a hearing aid is to help increase the frequencies of speech that are more difficult to hear due to hearing loss. Hearing aids in the past did not enhance high frequencies as well as current technology, and noise management technology has also dramatically improved which is increasing patients perceived benefit with over 80% of users expressing satisfaction with their hearing aids(12) The question on how hearing loss and cognitive decline are associated still remains.

Normal Hearing: The cow jumped over the moon.

Hearing Loss: _ _e _ow _um_ _ _ over _ _e moon.

Listen to hearing loss

There is an abundance of research which links accelerated cognitive decline and untreated hearing loss. Studies have shown that individuals with a mild, moderate and severe untreated hearing loss are twice, three times and five times as likely to develop dementia or exhibit accelerated cognitive decline as compared to their normal hearing peers, and that untreated hearing loss is linked to mild cognitive impairments not exhibited in those with hearing loss who opted treatment with hearing aids(2,8). Untreated hearing loss has also been linked to accelerated reduction in brain volume. Individuals with untreated hearing loss had an additional cubic centimeter of brain tissue atrophy as compared to their normal hearing counterparts when studied over a 10-year period(7) Hearing and the brain have a clear connection in that the ear functions to convert sound from the outside world into an electrical signal so the brain can interpret and process those signals into something meaningful. When an individual has hearing loss, there are gaps in the speech signal that are left open for interpretation, and this means the brain has to work harder to fill in the gaps, causing fatigue. Research has shown that individuals with untreated hearing loss show a reorganization of the brain and use of the frontal lobe which is unusual for hearing(3). The frontal lobe, amongst many other functions, is the region of the brain used for planning, executive function, problem solving, our personality and more. Researchers have theorized the frontal lobe is being accessed when there is untreated hearing loss because it is the problem-solving region of the brain, and with a hearing loss, there is an element of problem solving since the entire speech signal is not being heard, while the brain fills in the gaps. In addition to frontal lobe recruitment, studies have also shown that poorer cognition, ability to identify speech and more severe hearing loss was associated with greater cross-modal recruitment of the auditory cortex in the right hemisphere(6). This brain reorganization is possibly where the dementia link is made, although more research needs to be completed to substantiate these claims(3,4,5). Studies have shown that with a binaural hearing aid fitting, a decrease in cross-modal recruitment was identified in the auditory cortex, which corresponded with improvements in cognitive function and speech perception(6). Several studies also seem to indicate that treating hearing loss attenuates the accelerated cognitive decline exhibited in those with untreated hearing loss(1,4,6).

Increased Risk of Falls

Patients with hearing loss had an increased risk of falls, according to studies completed at John Hopkin’s University. Even those with a mild impairment were three times more likely to have increased risk of falling. The study found that each 10db increase in hearing loss increased an individual’s risk 1.4-fold as compared to those with normal hearing. The reason for this link? Researchers believe that decreased hearing also decreases an individual’s awareness of their environment, leading to more falls, likely due to the increased cognitive load imposed by untreated hearing loss(1)

Socioeconomic Impacts

Hearing loss has been associated to lower socioeconomic status, even when race, sex, age and education were accounted for. Individuals with hearing loss were 1.58 times higher risk of having lower income, and were 1.98 times more likely to be unemployed as compared to their normal hearing peers(1).

Individuals with untreated hearing loss were also shown to make $30 000 less in household income as compared to their normal hearing counterparts, depending on the degree of hearing loss. Hearing aids were shown to mitigate the disparity in income by 90-100% for those with a mild hearing loss, and 66-77% for those with a moderate or severe hearing loss(3).

While the stats might be surprising, hearing loss affects an individual’s ability to communicate effectively in a workplace, listen to directives from colleagues or management, and could even impact training for a new job. The simple act of using effective communication strategies combined with properly fit hearing aids can dramatically change daily communication in the workplace in a very positive way!

Increased Incidence of Depression and Reduced Quality of Life

When studying quality of life measure in elderly adults with untreated hearing loss, outcomes have shown that these adults have increased feelings of loneliness, isolation, dependence, frustration, anger, anxiety, embarrassment, guilt, as well as challenges with communication. They also reported feelings of confusion, difficulty focusing, distracting thoughts, decreased self-esteem, and communication disorders. A hearing impairment often means communication challenges, especially in group situations where having a conversation is more difficult. Often individuals with hearing loss withdraw socially as a result. In a large study of over 2500 participants, untreated hearing loss was associated with decreased quality of life and a decreased ability to communicate effectively. Untreated hearing loss was also linked to increased feelings of depression. Studies have shown that the use of hearing aids seems to decrease depressive symptoms and improve quality of life while increasing engagement socially.

Cardiovascular Events and Diabetes

The link between hearing loss, diabetes and cardiovascular events is likely due to the sensitivity of hair cells in the cochlea have to fluid imbalances in the endolymphatic, and perilymphatic fluids. These fluids are imperative to the health of hair cells and how they conduct sound information to the auditory nerve and higher levels of the brain. One study found that 85% of individuals diagnosed with a stroke also had a flat or a low frequency hearing loss(2).Researchers indicated that individuals with these audiometric configurations should be considered at risk for a cardiovascular event and that appropriate referrals should be made. When it comes to diabetes, individuals with diabetes were 2X as likely to have sensorineural hearing loss(1). Researchers surmise that the vascular impacts of diabetes reduce blood supply to the cochlea, and specifically, high blood glucose levels may damage vessels in the stria vascularis. The stria vascularis is responsible for maintaining homeostasis in the cochlea, and disruption of these cells impacts hair cell function, can cause hair cell death, and disrupts the biochemistry of the cochlear environment as a whole.

Contact info

Toronto Hearing Health Clinic is located in the lower level of the Magenta Health Centre next to Phipps Bakery, inside the Momentum Building

There is ample complimentary street parking and a Green P (location ID 047) on 125 Burnaby Blvd, behind the Starbucks and Summerhill Market. Please use the code ‘crosstown’ in the Green P Parking App for up to 2 hours of free parking

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