Noise is one of the most common causes of hearing loss and one of the most common occupational illnesses in the United States. A single shot from a shotgun or rifle, at close range, may permanently damage your hearing in an instant. Repeated exposures to loud machinery over an extended period of time can present serious risks to hearing.

According to the National Institute on Deafness and other Communication Disorders (NIDCD), 36 million Americans have hearing loss… This includes 17% of our adult population. The incidence of hearing loss increases with age. Approximately 1/3 of Americans between the age of 65 and 74, and nearly half of those over age 75, have hearing loss. Hearing loss is the third most chronic health condition facing older adults. Unfortunately, only 20% of those individuals who might benefit from treatment actually seek help. Most tend to delay treatment until they cannot communicate even in the best listening situations. On average, hearing aid users wait over ten years after their initial diagnosis to be fit with their first set of hearing aids.  

Hearing loss in an adult has a number of contributing factors... including age, genetics, noise exposure and chronic disease (eg, diabetes, chronic kidney disease, and heart disease). Age related hearing loss, or presbycusis, is generally a slow progressive hearing loss that affects both ears equally. Presbycusis begins in the high frequencies and later affects the mid and lower frequencies. One of the first signs of hearing loss is often the inability to hear and understand speech in noisy environments. Because of this slow progression, adults with presbycusis do not readily acknowledge their hearing loss, considering it to be a normal condition of aging. As audiologists, we are not surprised to hear that the spouse or significant other has been frustrated by the hearing loss long before the individual with the hearing loss even acknowledges it. It is this insidious nature of presbycusis that allows many adults to ignore their hearing loss for years or even decades. 

Several studies have documented the impact of untreated hearing loss. An often cited survey was commissioned by the National Council on Aging in 1999. This national survey of nearly 4,000 adults with hearing loss and their significant others, showed significantly higher rates of depression, anxiety and other psycho-social disorders in individuals with hearing loss who are not wearing hearing aids. This survey looked at the positive benefits of amplification (hearing aids), and showed that hearing aid use positively affected the quality of life for both the hearing aid wearer and his/her family. These findings were consistent with the findings of a large randomized and controlled study that determined that hearing loss was associated with decreased psycho-emotional well-being, decreased social/emotional well-being, decreased communication and decreased cognitive function, in addition to increased depression for subjects who do not use hearing aids (as compared to those who had received hearing aids). These conditions were all improved after hearing aids were fitted. More recently, Dr. Frank Lin and his colleagues at Johns-Hopkins University found a strong link between the degree of hearing loss and the risk for developing dementia. Individuals with mild hearing loss were twice as likely to develop dementia as those with normal hearing; those with moderate hearing loss were three times more likely; and those with severe hearing loss had five times the risk. While this study could not definitively conclude that early treatment with hearing aids would reduce the risk of dementia, there was a strong positive correlation between the degree of hearing loss and the risk of dementia (Lin et.al. 2011).

Regeneration of 'hair cells' (sensory cells) in the inner ear is something that human babies and mice can only do for a short period after birth. Dr. Ksenia Gnedea and her colleagues at the A. James Hudspeth's Laboratory of Sensory Neurosciences have made some progress in activating sensory regeneration of these hair cells in mature mice. (Proceedings of the National Academy of Sciences. Oct. 2015).

Scientists at the National institue on Deafness and other Communication Disorders have recently had success in treating mice with defective inner ears with gene therapy. A particular mutated gene (whirlin) can cause defects in the inner ears of humans and mice. Although not effective in mature mice, newborn mice with the the defective whirlin gene developed normal inner ear stereocilia (hair cells) when injected with the normal whirlin gene. (Molecular Therapy. October 2015)