Overview - ISO 8253-1:2010 (Pure‑tone air and bone conduction audiometry)
ISO 8253-1:2010 specifies internationally harmonized procedures and requirements for conducting pure‑tone air conduction and bone conduction threshold audiometry. It defines how to measure hearing thresholds using earphones and bone vibrators, the roles of different audiometer types (manual, automatic recording, computer‑controlled), and the environmental and equipment requirements needed to obtain reliable results. The standard covers screening procedures (air conduction only) and notes limitations for special populations (e.g., very young children). It does not cover speech audiometry, electrophysiological methods, or sound‑field loudspeaker testing.
Key technical topics and requirements
- Threshold determination methods: Procedures for fixed‑frequency and sweep‑frequency pure‑tone audiometry, with methods suitable for manual, automatic, and computer‑controlled audiometers.
- Transducers and reference levels: use of earphones and bone vibrators referenced to RETSPL (reference equivalent threshold sound pressure level) and RETVFL (reference equivalent threshold vibratory force level), as defined in the ISO 389 series.
- Equipment requirements and calibration: Audiometer performance, routine checks and a staged calibration scheme (routine subjective checks, periodic objective checks, and basic calibration tests) to ensure long‑term accuracy.
- Ambient noise and test environment: Maximum permissible ambient noise levels and psychoacoustic checks to avoid masking of threshold tones during testing.
- Test administration: Preparation and instruction of test subjects, transducer placement, test time considerations, and the requirement for a qualified tester.
- Bone conduction specifics: Guidance on occlusion effects, airborne sound radiation from bone vibrators, vibrotactile sensations, and masking procedures.
- Documentation and uncertainty: Audiogram presentation, maintenance of measurement uncertainty (Annex A), and test reporting.
Practical applications and users
ISO 8253-1 is applied where accurate pure‑tone hearing thresholds are required:
- Clinical audiology and ENT clinics performing diagnostic audiometry
- Occupational health and hearing conservation programs (screening and monitoring)
- Hearing aid fitting and verification baseline assessments
- Manufacturers and service providers of audiometric equipment for design, test, and calibration
- Calibration laboratories and biomedical engineers responsible for routine equipment checks
The standard helps ensure consistent, reproducible hearing threshold measurements across clinical, industrial, and research settings. Note: adaptations may be required for special populations (infants, cognitively impaired, frail elderly).
Related standards
Keywords: ISO 8253-1, audiometric test methods, pure‑tone audiometry, air conduction, bone conduction, RETSPL, RETVFL, audiometer calibration, screening audiometry, ambient noise, audiogram.