What is Hearing Loss?
Hearing loss occurs when our ability to detect and process sound is hindered. The auditory process involves both your ears and your brain. Sounds are received in waves, picked up by the outer ear. The waves move through the middle ear and are amplified by the eardrum before they are sent to the inner ear. In the inner ear, hair cells translate the vibrations into neural signals, which are then sent to the brain to be processed as sounds we recognize. Hearing loss may affect one or more steps of this process, interfering with our ability to pick up and process sounds.
Prevalence of Hearing Loss
Hearing loss is the third most common medical condition in the United States. Approximately 48 million Americans – 60% of the population – experience some degree of hearing loss, from mild to profound. Though hearing loss may affect anyone at any age, it is most common in people over the age of 65. One third of people between age 65 and 74 experience hearing loss, with the number increasing to 50% for people age 75 and older.
In the workforce, 60% of people experience hearing loss. The US Department of Labor has reported an increase in occupationally-related hearing loss in the past 25 years. Sixty-percent of veterans returning from combat zones in Iraq and Afghanistan report cases hearing loss and tinnitus (ringing of the ears) – due to exposure to noise.
Signs of Hearing Loss
Because hearing is an invisible sense, the signs of hearing loss are not apparent at first. Often times, hearing loss happens gradually and subtly.
Common signs of hearing loss include:
(Source: Hearing Loss Association of America http://www.hearingloss.org/content/symptoms-hearing-loss)
Causes and Types of Hearing Loss
There are three main types of hearing loss: conductive, sensorineural, and mixed.
Conductive hearing loss is usually located in the outer and middle parts of the ear, interfering with the ear’s ability to pick up sound. Conductive hearing loss is caused by issues with the ear canal, ear drum, and middle ear bones (malleus, incus, and stapes). Other causes may include ear infection, perforated eardrums, poor Eustachian tube function, tumors, impacted earwax, or otosclerosis.
Sensorineural hearing loss is located in the inner ear, and results from the inner ear hair cells’ ability to translate sound waves into neural signals. Hair cells do not regenerate if they are damaged, which leads to hearing loss. Sensorineural hearing loss is caused by the natural process of aging, exposure to loud sounds (whether in a single event or over a long period of time), head trauma, hereditary factors, Meniere’s disease, or malformation of the inner ear. Ototoxic medication – drugs that are toxic to the ear – may also cause death of inner ear hair cells.
Mixed hearing loss is a combination of conductive and sensorineural hearing loss, affecting various parts of the ear.
Identifying and Treating Hearing Loss
Hearing specialists estimate that people wait an average of seven years from the time they first notice changes in their hearing ability to take a hearing exam. Identifying and treating hearing loss early on is crucial to one’s personal and medical well-being.
Hearing loss is identified through a series of comprehensive hearing exams. These exams are painless and noninvasive, and they reveal your hearing abilities and the configuration of hearing loss to you and your hearing professional. From these results, hearing loss is treatable with the use of hearing aids, which amplify sound and provide clearer signals for your ears and brain to process.