Noise-Induced Hearing Loss (NIHL)
Permanent damage to the cochlear hair cells caused by repeated exposure to harmful noise without adequate protection.
- Audiologically NIHL typically presents as a high-frequency notch on pure-tone audiometry, often centred around 4 kHz with some recovery at higher frequencies.
- It is irreversible. Hearing aids amplify what remains; they do not restore lost frequencies.
- Common military causes include small-arms ranges, support weapons, mortars, artillery, demolitions, armoured vehicle interiors, jet and helicopter operations, and ship machinery spaces.