Different Types of Hearing Loss
Hearing Loss Overview
Hearing loss is a surprisingly common condition that can affect anyone at any age, from newborns to seniors. Hearing loss can occur for a number of reasons, including medical conditions, reactions to medications, loud noise exposure, genetics, and the natural aging process.
Hearing loss is described by the type of loss (as explained below) and the degree of loss. Degrees of loss include: Mild, Moderate, Moderately-Severe, Severe, and Profound. The degree of hearing loss may vary across the frequency or pitch range. For example, someone may have just a mild loss in the low-pitched range, and a severe loss in the high pitches.
The degree of loss at each pitch impacts how sounds are perceived. Generally, hearing loss in the low pitches affects the ability to hear vowel sounds, and also impacts the overall volume that sounds are perceived. Hearing loss in the high pitches doesn't affect volume as much, but rather clarity.
Because it is common to develop hearing loss in the high pitches first, many people describe their hearing loss like this: "I can hear fine, but I don't always hear clearly". That's because they're hearing the volume (good low-pitch hearing), but they're missing the clarity (poor hearing in the high pitches).
Types of Hearing Loss
Hearing loss can happen for a variety of reasons. The type of your hearing loss will also help to determine the best course of treatment. Your audiologist will be able to determine the type of your hearing loss based on your test results, and will explain the recommended next steps.
Conductive Hearing Loss
This type of hearing loss occurs when sound isn’t conducted through the ear canal, eardrum, or bones of the middle ear correctly. Conductive hearing loss can have a variety of causes. In some cases conductive hearing loss can be treated using medication or surgery by a physician. In more long-standing or permanent cases hearing aids may be a recommended treatment option. With this type of hearing loss there is not damage to the inner ear or the cochlea. Causes of conductive hearing loss include:
- Fluid in the middle ear
- Ear infections
- Ruptured eardrum
- Damage to the bones of the middle ear
- Occluded earwax in the outer ear
- Scarring on the eardrum
- Absence or deformity of the outer ear
Individuals with conductive hearing loss may report that sounds are muffled or quiet. Generally, when sounds are made louder, these individuals can hear well again.
Sensorineural Hearing Loss
Sensorineural hearing loss occurs as a results of damage to the cells of the inner ear or abnormalities of the neural pathway to the auditory region in the brain. This is the most common form of permanent hearing loss, and often cannot be treated medically. With sensorineural hearing loss, sounds may be muffled or unclear. A person with this type of hearing loss may have trouble understanding speech in noisy environments and may also experience tinnitus or ringing in the ear. Some causes of sensorineural hearing loss include:
- Chronic exposure to loud noise
- Exposure to sudden, extremely loud noise
- Viral or bacterial infection of the inner ear
- Drugs that are ototoxic (toxic to the ear)
- Head injury
Mixed Hearing Loss
Occasionally there may be a combination of causes that compound upon each other. For example, if a person has a hole in their eardrum causing a conductive hearing loss, and damage to the cells of the inner ear from loud noise causing a sensorineural hearing loss, the net hearing loss is called a “mixed” hearing loss. While the conductive component may be medically treatable, it is unlikely that the sensorineural component is, and hearing aids are a common course of treatment.
Neural Hearing Loss
Neural hearing loss when there nerve impulses aren't carried to the brain by the auditory nerve correctly. This could be because of a lesion to the nerve, or the nerve could be missing or may have been medically severed. Some causes of neural hearing loss include genetics, acoustic tumors, in-utero exposure to certain infections, severe jaundice in infancy and low birth weight associated with premature birth.
Individuals with neural hearing loss may have difficulty with speech understanding, and the course of treatment varies. In same cases, hearing aids are the best solution to improve communication abilities.