Overview
ISO 7029:2017 - Acoustics: Statistical distribution of hearing thresholds related to age and gender describes the expected statistical behaviour of pure‑tone hearing thresholds for otologically normal persons. It gives age‑ and gender‑dependent median hearing‑threshold deviations and the statistical distribution around those medians for standard audiometric frequencies under monaural earphone conditions. The main frequency range is 125 Hz to 8 000 Hz (age range 18–80 years); additional median values for 9 000–12 500 Hz (ages 22–80) are provided for information.
Key topics and technical requirements
- Population and conditions: Applies to otologically normal people (no ear disease, obstructing wax, undue noise or ototoxic exposure, or familial hearing loss) using monaural earphone audiometry.
- Median hearing‑threshold deviation: The standard defines the expected median threshold deviation relative to the median 18‑year‑old of the same gender and supplies formulae and tabulated coefficients (α, β) to calculate these medians across ages and frequencies.
- Distribution around the median: Uses an approximation of the distribution by the upper and lower halves of two Gaussian distributions, with separate standard deviations (s_u, s_l). Coefficients γn are tabulated separately for males and females and across frequencies.
- Age and frequency limits: Full statistical data for ages 18–80 at 125–8 000 Hz. For 3 000–8 000 Hz, values above age 70 are informational (greater uncertainty). High‑frequency medians (9–12.5 kHz) are informational only.
- Supporting material: Informative annexes include Gaussian tables, worked numerical examples, median tables, derivation notes, and uncertainty (RMSE) information.
Applications and who uses it
ISO 7029:2017 is widely used by:
- Audiologists and clinicians - to interpret audiograms in relation to age‑expected thresholds.
- Occupational health and hearing conservation professionals - to separate age‑related hearing components when evaluating noise‑induced hearing loss and for medico‑legal assessments.
- Acoustical and biomedical researchers - for population modelling of hearing sensitivity and epidemiological studies.
- Standards writers and product/test labs - as a reference database for normative hearing and for use alongside ISO 1999 (noise‑induced hearing‑loss prediction).
- Regulators and insurers - for consistent, evidence‑based assessment criteria in compensation and policy contexts.
Practical uses include estimating the portion of observed hearing loss attributable to ageing, benchmarking populations against age‑norms, and informing hearing‑conservation program design. Note: ISO 7029 describes population statistics - it cannot attribute with certainty the cause of an individual’s hearing loss.
Related standards
Keywords: ISO 7029:2017, hearing thresholds, age‑related hearing loss, audiometry standards, statistical distribution, median hearing threshold, otologically normal, ISO 1999.
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