Hearing loss, or a hearing impairment, occurs when a person’s ear has decreased sensitivity to normally produced sounds. The level of hearing loss for a given person is measured generally by the increase in volume needed for a person to detect the sound.
There are three types of hearing loss, and each of those types can occur in either both ears (bilateral) or a single ear (unilateral)
- Conductive hearing loss occurs when sound isn’t reaching the inner ear adequately
- This can be the result of any number of causes for obstruction, such as scar tissue or dysfunction of the middle ear
- Sensorineural hearing loss occurs from damage to the inner ear, or cochlea, and therefore in what is communicated to the brain
- This can be caused by general aging (and the impact to the cells of the cochlea), noise exposure, head trauma and more
- Mixed hearing loss occurs when there is a combination of both conductive and sensorineural hearing loss
Hearing loss is determined by measuring the volume level at which a sound must be amplified (above the normal threshold) before a person identifies it. The ability (or inability) to detect a sound can also be related to the frequency of the sound. As such, the varying levels of volume are tested against different frequencies.