Before we describe the types of hearing loss a person may have, it’s useful to know that sound is measured by:
its loudness or intensity (measured in units called decibels, dB); and
its frequency or pitch (measured in units called hertz, Hz).
Hearing loss is generally described as slight, mild, moderate, severe, or profound, depending upon how well a person can hear the intensities or frequencies most strongly associated with speech. Impairments in hearing can occur in either or both areas, and may exist in only one ear or in both ears. Generally, only children whose hearing loss is greater than 90 decibels (dB) are considered deaf.
Regardless of the cause, hearing loss falls into the following categories depending on the part of the ear that’s affected