By: Kelsey Keimig
When diagnosing a hearing loss, audiologists use classifying terms including: conductive, sensorineural, and mixed, but what does this mean? To understand the type of hearing loss you have, we must first understand the parts of the ear.
The ear is divided into three primary sections: outer, middle, and inner ear.
The outer ear includes the flesh portion of the ear, the ear canal, and the ear drum.
The middle ear is an air-filled space behind the eardrum and houses a chain of three small bones (Malleus, Incus, and Stapes) which help transmit sound through the ear, and the Eustachian tube which connects the middle ear to the throat.
The inner ear is a fluid filled space comprised of the cochlea (the hearing organ), and the cochlear nerve (cranial nerve 8). The cochlea contains tiny sensory hair cells which transmit sound to the cochlear nerve. The inner ear also houses part of the vestibular system, which is responsible for balance.
Now that I’ve broken down the parts of the ear lets discuss the way hearing loss is classified.
A conductive hearing loss means the issue is stemming from either the outer or middle ear. Some examples of causes of conductive hearing losses include: a closed off ear canal (atresia), ear infections in the outer or middle ear, fluid accumulation in the middle ear, and the separation of the middle ear bones. Typically, the inner ear is healthy and intact.
A sensorineural hearing loss means the hearing loss is occurring in the inner ear. The issue can be with the cochlea, cochlear nerve, or both. This type of loss can occur from: loss of function of the sensory hair cells (typically age-related hearing loss), poor nerve transmission, demyelization of the nerve, and growth of a tumor on the nerve, which will suppress function. Typically, the outer and middle ear are healthy and intact.
A mixed hearing loss means there is a combination of problems resulting from the outer or middle ear and the inner ear. An example we commonly see is having age-related hearing loss and the individual develops an ear infection.
As your ear-tour guide, I hope you have a better understanding of your hearing loss. If you’re not sure of the type of hearing loss you have, talk to your audiologist about solutions to improve your hearing.