Noise-induced hearing loss produces a characteristic 3000–6000 Hz notch in the audiogram

An audiogram plots a person’s hearing threshold (quietest audible tone) across frequencies. Normal adult thresholds are 25 dB HL or better. Noise exposure initially damages the cochlear hair cells tuned to 3000–6000 Hz, producing a distinctive dip — called a notch — in that frequency range on the audiogram. Lower and higher frequencies remain normal early on. The notch pattern is diagnostically significant: it distinguishes noise-induced loss from age-related or other hearing loss types. Audiometric testing detects the notch before the person perceives significant hearing difficulty, enabling early intervention.

Examples

A DJ who has worked loud clubs for five years without hearing protection may show normal thresholds at 250–2000 Hz and at 8000 Hz, but a significant dip at 4000 Hz — the classic noise notch.

Assessment

Describe what a noise-induced hearing loss audiogram looks like and explain why the high-frequency notch appears before the person notices speech comprehension problems.