What are the Different Types of Hearing Loss?
There are three types of hearing loss: conductive, sensorineural, and mixed hearing loss.
Conductive hearing loss is localized to the outer and middle ear structures. Conductive hearing loss might occur due to congenital malformations of the ear canal and middle ear structures or head trauma, infections, tumors, impacted earwax, or other medical conditions.
Sensorineural hearing loss refers to problems with the inner ear structure and the process by which sound waves are transformed into electric signals sent to the brain. Exposure to loud noise, aging, and Meniere’s disease are all related to sensorineural hearing loss.
Mixed hearing loss is the combination of both conductive and sensorineural hearing losses, in which different elements of the auditory system (outer, middle, and inner ear) are damaged or affected by any combination of the above conditions.
Understanding Sensorineural Hearing Loss
According to the American Hearing Loss Foundation, sensorineural hearing loss is “the most common type of hearing loss, occurring in 23% of population older than 65 years of age.” Sensorineural hearing loss pertains to the inner ear, which is made up of the auditory-vestibular nerve, the cochlea, and the vestibular system (which consists of semi-circular canals).
Sound waves enter the ear and are transformed by the inner ear into signals that are sent to the brain, which registers this signal as a sound. Sensorineural hearing loss occurs when there is damage to the cochlea or the nerve pathways between the inner ear and the brain. This kind of hearing loss, often permanent, has different causes.
Causes of Sensorineural Hearing Loss
Sensorineural hearing loss may be congenital, meaning it is caused by inherited genetics. In some cases, the malformation of the inner ear results in hearing loss. Certain infections transmitted from mother to infant may lead to sensorineural hearing loss as well, such as rubella or human Cytomegalovirus (HCMV). In terms of acquired diseases, mumps, syphilis, bacterial meningitis, and autoimmune diseases may all contribute to sensorineural hearing loss.
Unfortunately, some medications used to treat the aforementioned diseases may also cause sensorineural hearing loss by irreparably damaging the hair cells of the inner ear, which do not regenerate. This problem is known as ototoxicity, or “ear poisoning.” Though there are at least 100 classes of drugs that cause inner ear hearing loss, the most common ones are aminoglycoside antibiotics (used to treat bacterial infections, such as meningitis), loop diuretics, and antimetabolites. Researchers are currently in the process of finding alternatives to these drugs, as well as patenting a new aminoglycoside antibiotic that is effective in fighting the specific disease without damaging inner ear cells.
Both presbycusis (age-related) and noise-induced hearing loss are forms of sensorineural hearing loss. While presbycusis occurs naturally, noise-induced hearing loss is preventable if you take the proper precautions with exposure to noise in your life. Exposure to loud noises, 90 decibels and higher, for an extended period of time, may lead to sensorineural hearing loss.
Physical trauma is another common cause for sensorineural hearing loss. Injury to the temporal bone may affect the cochlea, while other head and neck injuries may affect the auditory system. Tumors in the head and neck area may also cause sensorineural hearing loss by creating pressure against certain processing centers of the brain and within the inner ear.
Though conditions surrounding the causes of sensorineural hearing loss may be corrected, such as removal of tumors, drainage of fluids within the inner ear, or eradication of certain diseases, the effects of sensorineural hearing loss are usually permanent. The use of a hearing aid drastically improves the lives of people suffering from sensorineural hearing loss.
Treating Sensorineural Hearing Loss
While hearing loss is the third most common medical condition in the US, the way in which it manifests will differ from person to person. With hearing loss, it is important to remember that hearing happens in the brain. In other words, we recognize sounds in our daily life because the information to recognize them has been stored in our brains.
As such, hearing is an incredibly personalized experience and for this reason, there is no “one-size-fits-all” solution for hearing loss that is easily found over the counter. If you’ve experienced changes in your hearing, it is important to seek professional care.
When you visit us at Kenwood Hearing Centers, our friendly team will provide a comprehensive hearing exam. If a hearing loss is present, your audiogram will indicate the degree and configuration of the hearing loss. From these results, we will also be able determine the type of hearing loss and from there, we will work with you to find the best solution for your hearing needs.
For more information, contact us at Kenwood Hearing Centers.