For those of us born with a hearing loss, it’s called congenital, meaning “a disease or physical abnormality present at birth” Any hearing loss which occurs after birth at any point is referred to as acquired hearing loss. In 2019 approximately 6,000 U.S. infants born in 2019 were identified early with a permanent hearing loss with a prevalence of 1.7 per 1,000 babies screened. Genes account for around 50 to 60 percent of cases of congenital hearing loss, with viruses and disease contracted during pregnancy being the second most common cause.
While in relation to births in the US congenital hearing loss is rare and tested for in 98 percent of babies born, acquired hearing loss is much more common as it can occur at any time after birth.
Conductive vs. sensorineural hearing loss
There are three types of acquired hearing loss: sensorineural, conductive and a mix of both. 90 percent of people with hearing loss have sensorineural. Sensorineural hearing loss occurs when tiny hair-like cells within the inner called stereocilia become damaged. While we collect sound with our ears, it’s the job of the stereocilia to transform these sounds into electrical impulses which can be received and interpreted by the brain.
Conductive hearing loss occurs when sound can’t pass through your outer or middle ear due to a blockage. Common causes of conductive hearing loss include: fluid buildup
- A buildup of fluid
- Ear infection
- Punctured eardrum
- benign tumors
- an impaction of earwax
- obstruction by foreign objects
- deformations in the outer or middle ear
Causes of Acquired Sensorineural Hearing Loss
The stereocilia are incredibly fragile and can become damaged by a wide range of causes. Some of the most common include:
Age Related Hearing Loss: The most common cause of hearing loss, age related hearing loss, also known as presbycusis affects one in three adults 65 and older and one in two 75 years and up. It occurs due to changes in the ear as we age but the risk may be increased by health and lifestyle choices earlier in life.
Noise Induced Hearing Loss: The second most common cause of hearing loss. The loudness or volume of sound is measured in decibels (dBA). We can listen to sounds indefinitely without sustaining damage, but when sounds surpass safe listening threshold, the vibrations of sound can be severe enough to cause lasting damage to the inner ear, causing stereocilia to shatter against the cell membrane which houses them. The threshold for safe listening is an exposure of 85 dBA for eight hours. After this point our ears are at risk. As the decibels rise the time, we can withstand an exposure decrease.
For every three incremental increase in decibels the exposure time is cut in half. For instance, at 88 dBA, it only takes 4 hours for damage to occur and by the time it reaches 95 dBA, it only takes an hour. The Center for Disease Control and Prevention (CDC) reports “An estimated 12.5% of children and adolescents aged 6–19 years (approximately 5.2 million) and 17% of adults aged 20–69 years (approximately 26 million) have suffered permanent damage to their hearing from excessive exposure to noise.”
Ototoxic Medications: Certain prescription and over the counter medications are considered ototoxic which means they can put the integrity of the inner ear at risk. there are more than 200 medications and chemicals that are known to cause hearing and balance problems. The most common reported ototoxic drugs in clinical use include certain antibiotics, chemotherapeutic agents such as cisplatin, loop diuretics, antimalarials, and over the counter painkillers such as non-steroidal anti-inflammatory drugs (NSAIDs) and acetaminophen. Talk to your doctor when taking these medications and limit your use when possible.
Traumatic Brain Injuries: Impact to the head can not only cause brain damage but can injure the stereocilia of the inner ear causing permanent hearing loss.
Chronic Health Conditions: Many people are surprised to find that chronic health conditions such as diabetes, hypertension, cardiovascular disease and osteoporosis may increase the risk of sensorineural hearing loss. Many of these diseases compromise the flow of blood throughout the body, including the inner ear. Stereocilia rely on an ample supply of blood for optimal health. Regular exercise, and a balanced diet can reduce the risk.
If you suspect that you have an acquired hearing loss it’s important to treat it as soon as possible. The first step is as easy as scheduling a hearing exam with us today.