Degrees of Hearing Loss
A classification system for degrees of hearing loss, based on threshold hearing levels.
The degree of hearing loss a person has can be characterized by how loud a sound has to be in order for the person to be able to hear it. For a person with normal, healthy hearing, the faintest sound that can be heard is 0 decibels, but for someone with a
a sound must be louder than 0 dB before it can be heard. A hearing test can measure the softest sound that the person can detect. The higher a person's hearing threshold, the higher the degree of hearing loss that person has.
measuring a person's hearing level,
a range of frequencies (pitches) are used, and the
hearing threshold at each frequency
will be determined for each ear. The resulting
gives a detailed view of the nature of the hearing loss, which is essential in order to know what treatments may help. To arrive at a single number that is used as the overall threshold hearing level, only the better ear is used, and the threshold levels for that ear are averaged across the frequencies tested.
Knowing the person's overall threshold hearing level from the hearing test results, we can classify the degree of hearing loss, from slight to profound. There is no standard classification system that is universally used, but one system commonly used is the one recognized by the Hearing Loss Association of America:
|Degree of Hearing Loss||Threshold Hearing Level (dB HL)||Effect on Communication||Use of Hearing Aids|
|Normal||−10–15||no hearing impairment|| |
|Slight||16–25||speech understanding not affected|| |
||26–40||speech understanding reduced, especially in noisy environments||may be helpful|
|Moderate||41–55||conversation noticeably difficult||highly beneficial; strongly recommended|
|Moderately severe||56–70||speakers must raise their voice to be heard||essential|
|Severe||71–90||conversational speech cannot be heard||of less benefit|
|Profound||91 or higher||deaf||of little benefit; cochlear implants may be considered|
For reference, note that
conversational speech is around 60 dB.
Leave this page (Degrees of Hearing Loss) and go → Back to Effects of Noise Pollution
Leave this page (Degrees of Hearing Loss) and go → Back to Noise Help home page