What are the different kinds of Hearing Loss?
A complete hearing evaluation (audiogram) performed by an audiologist in a soundproof chamber in an otologist's or ENT's office can determine what type of hearing loss you have.
Hearing loss is a common medical condition but is often underdiagnosed. There are two major types of hearing loss – conductive hearing loss and sensorineural hearing loss. Both categories of hearing loss can occur gradually or suddenly. A sudden hearing loss, especially in one ear, can be a medical emergency.
Conductive hearing loss occurs when sound cannot reach the inner ear due to a problem of the outer or middle ear. Common problems that can cause conductive hearing loss include ear wax (cerumen), outer ear infection (otitis externa or swimmers ear), a hole in the eardrum (tympanic membrane perforation), negative pressure of the middle ear (Eustachian tube dysfunction), or fluid in the middle ear (otitis media).
Other causes of conductive hearing loss can include a tumor, or cyst in the middle ear (cholesteatoma), damage of the hearing bones (ossicles) due to negative pressure changes/infection/previous ear surgery, or stiffening of the joints of the ossicles (such as otosclerosis).
Less common causes of conductive hearing loss can include abnormalities of the inner ear, such as superior semicircular canal dehiscence (SSCD) or large vestibular aqueduct syndrome (LVAS).
Sensorineural hearing loss (SNHL) occurs following a problem of the inner ear. The hair cells and nerves of the inner ear, or cochlea, are damaged or lost in sensorineural hearing loss.
SNHL is the most common neurologic disability in the U.S. Aging is associated with hearing loss, and this is common condition called presbycusis. One third of patients over 60 years old and one half of patients over 85 have hearing loss. Noise exposure, either at work or recreationally, is another important cause of sensorineural hearing loss. A patient will often note a history of hearing loss in the family, suggesting that there may be genetic factors in certain individuals with sensorineural hearing loss. In some cases, autoimmune factors can cause fluctuating hearing loss in both ears. Other conditions of the inner ear that cause dizziness, like Menieres disease, are associated with SNHL. A severe head injury or skull fracture can cause conductive or sensorineural hearing loss. In rare cases, a benign tumor called a vestibular schwannoma (acoustic neuroma) can cause gradual or sudden sensorineural hearing loss in one ear.
Finally, there are some patients that have both a conductive and sensorineural hearing loss in the same ear.
- The three major parts of the human ear are the external ear, the middle ear, and the inner ear.
- A problem in the external or middle ear can cause conductive hearing loss.
- Most types of conductive hearing loss are potentially reversible.
- A problem of the inner ear (cochlea and auditory nerve) can cause sensorineural hearing loss.
- Sensorineural hearing loss is generally a permanent condition unless the hearing loss fluctuates or was sudden in onset.
- Sudden sensorineural hearing loss in one ear is a MEDICAL EMERGENCY. This is not treated by decongestants or antibiotics. If you think you have sudden deafness in one ear, you must seek care by a specialist AS SOON AS POSSIBLE. You may be a candidate for high dose oral steroids or steroids injected into the middle ear. Contact www.suddendeafness.org for more information.
- Both conductive and sensorineural hearing loss can occur either gradually or suddenly.
- A complete medical evaluation by an otolaryngologist or otologist and audiologic evaluation by an audiologist is important before determining if the hearing loss is correctible with medication, surgery, or hearing aids.