Causes and Consequences of ARHL
Causes of ARHL
In general, ARHL is caused by changes in the inner ear as we age, but genetics, noise exposure, certain medications, smoking, and chronic diseases such as diabetes, kidney disease, and cardiovascular disease can contribute to the progression of ARHL.
Tiny hair cells lining the cochlea (a sensory organ inside the inner ear) pick up sound waves and transform them into nerve signals that the brain interprets as sound. ARHL typically occurs when hair cells become damaged over time or die, a condition leading to permanent hearing loss.
The following figure shows the path sound waves travel through the ear drum to the Cochlea, where the hair cells live, work, and play. Here is a video of the hearing process.
The next figure illustrates the relationship between the hair cells lining the Cochlea and sound frequency detection. The hair cells lining the cochlea have varying sensitivity for detecting sounds of different frequencies. Hair cells located at the base of the Cochlea detect higher frequency sounds. Middle frequencies are detected by hair cells at the center of the winding Cochlea, and hair cells at the apex of the Cochlea detect lower tones. ARHL usually begins with high frequency hearing loss (degeneration of the hair cells lining the bottom of the Cochlea) and later affects the lower frequencies at the apex of the Cochlea.
Hair Cell Degeneration Due to Aging
The left half of the next figure shows banks of healthy hair cells lining the Cochlea. The right half of the figure shows hair cell damage from a research study by Dr. Li-Korotky… Age-Related Degeneration of the Organ of Corti in Two Genotypes of Mice… using a mouse model to gain insights into human hair cell degeneration due to aging.
This particular research examined hair cell degeneration in mice with different gene structures, leading to different hearing loss results as the mice aged. A scanning electron microscope reveals hair cell damage (hair cells bent over and damaged) due to aging.
Consequences of Untreated ARHL
Untreated hearing loss can lead to or enhance the effects of serious cognitive disorders and emotional conditions such as dementia, Alzheimer’s disease, and depression, according to a recent study from the National Institute of Aging. The risk for these disorders increases with increasing levels of hearing loss; for every 10 decibels of hearing loss, the chance of developing severe cognitive disorders increases by 20 percent.
Another recent study ( Hearing Loss and Incident Dementia) by the Johns Hopkins School of medicine found a strong link between untreated hearing loss and the development of dementia. A study by Johns Hopkins experts, found that older adults with hearing loss are more likely than peers with normal hearing to require hospitalization and suffer from periods of inactivity and depression. These and other studies indicate that hearing deficits can lead to social isolation, resulting in physical and mental declines.
Untreated hearing loss also leads to serious negative lifestyle changes, which often effect family, friends, and others. These changes include threats to personal safety; irritability; pessimism; anger; fatigue; tension; stress; isolation; withdrawal; and diminished health.
Mounting evidence of serious consequences resulting from untreated hearing loss underscore why hearing loss should not be considered merely an annoying part of aging, but an important issue for public health.
Here’s the good news…
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Hearing loss increases with age. Approximately one third of Americans between 65 and 74 and nearly half of those over 75 have hearing and communication problems. Learn more, here
Simply put, the louder the sound, the shorter the time before damage occurs… there are no treatments…not medicine, not surgery, not hearing aids…that can restore your hearing once it is damaged by noise. Learn more, here