noise-induced hearing loss
Permanent or temporary reduction in hearing sensitivity resulting from exposure to hazardous levels of sound, characterised by a notch in the audiogram typically centred at 4000 Hz.
Full Definition
Noise-induced hearing loss (NIHL) results from acute or chronic exposure to sound levels sufficient to damage cochlear outer hair cells, particularly at frequencies around 3000–6000 Hz, with a classic audiometric notch at 4 kHz and partial recovery at 8 kHz. Occupational noise exposure and recreational sources (firearms, loud music) are primary causes. Temporary threshold shift (TTS) refers to a reversible elevation in thresholds following noise exposure, whereas permanent threshold shift (PTS) indicates irreversible damage. Editors should hyphenate the full term as a compound modifier (noise-induced hearing loss) and ensure NIHL is expanded on first use. The condition must be distinguished from presbycusis, which also causes high-frequency loss but through age-related mechanisms.
Usage
Usage note: Always hyphenate 'noise-induced' as a compound modifier. Distinguish from 'acoustic trauma,' which refers to a single-incident exposure rather than chronic exposure. Expand NIHL on first use.
In Context
- "The occupational health report confirmed noise-induced hearing loss consistent with 20 years of unprotected exposure in a manufacturing environment." — Occupational health assessment
- "The characteristic 4 kHz audiometric notch is a hallmark of NIHL and distinguishes it from age-related hearing decline." — Clinical audiology textbook