The loss of hearing ability characterized by decreased sensitivity to sound in comparison to normal hearing. Hearing loss may be conductive, sensorineural, or mixed. Hearing loss ranges from slight to profound. Typically the classes of hearing loss are based on the average hearing loss at 500 Hz, 1000 Hz and 2000 Hz. Here is one commonly used classification.
- Normal hearing: -10 to 15 dB
- Slight loss: 16 to 25 dB
- Mild loss: 26 to 40 dB
- Moderate loss: 41 to 55 dB
- Moderately severe loss: 56 to 70 dB
- Severe loss: 71 to 90 dB
- Profound loss: 91 to 120 dB