hearing loss
We weigh ourselves in kilograms, pounds or stone; measure our height in meters, feet or inches; monitor our heart rate in beats per minute. How do we measure hearing?
Our hearing organs perceive sound as pitch and loudness, respectively as frequency and intensity. Low frequency sound waves produce low pitched, bass sounds while high frequencies produce high pitched, whistle sounds.
Decibels (dB) are the unit used to quantify loudness (our hearing’s perception of sound intensity). A pleasant conversation, for example, has the intensity of 60 dB, a lawn mower up to 100 dB. Our ears respond to intensities between -10 dB and 120 dB.
The severity of a hearing impairment depends on how loud a sound must be before an individual hears it. Degrees of hearing loss are categorized as follows:
 |
 |
| Mild: 20dB to 40dB |
Severe: 65dB to 90dB |
| Moderate: 40dB to 65dB |
Profound: greater than 90dB |