ISO 8253-3:2022

Overview

ISO 8253-3:2022 - "Acoustics - Audiometric test methods - Part 3: Speech audiometry" specifies standardized methods for speech recognition tests used in audiological applications. The standard defines requirements for the composition, recording, validation and evaluation of speech test materials, procedures for delivering recorded speech through an audiometer and transducers (earphones, bone vibrator, sound‑field loudspeakers), and methods for using noise for masking or as a competing sound. It focuses on ensuring precision and comparability across different languages and test procedures while noting that content of speech materials is language‑dependent.

Key topics and technical requirements

• Recording of speech material: calibration signals, reference recordings, recording environment and setup, and required signal levels.
• Test material validation: determination of reference speech recognition curves, perceptual and phonemic equivalence across test lists, and test–retest reliability.
• Speech audiometry procedures: device and transducer requirements, ambient sound pressure limits for test rooms, sound‑field audiometry considerations, and presentation formats.
• Thresholds and scoring: methods to determine speech detection threshold, speech recognition threshold, and speech recognition scores (including fixed SNR and threshold with competing sounds).
• Masking and competing sound: procedures for contralateral masking and presentation of competing sound (types, levels, and test procedures).
• Quality assurance: measurement uncertainty, maintenance and calibration regimes (routine checks, periodic electroacoustic tests, basic calibration stages).
• Documentation and formats: recommended format for speech audiograms and documentation of validation and calibration.
• Informative annexes: examples of speech materials and competing sounds, typical results, methods for optimizing perceptual equivalence, and guidance on minimum sample sizes and uncertainty.

Applications and users

ISO 8253-3 is used by:

• Audiologists and clinicians for standardized speech audiometry in diagnostic evaluation and hearing rehabilitation.
• Clinical engineers and hearing‑care professionals for equipment setup, calibration, and room compliance.
• Manufacturers of audiometers and transducers to ensure recorded speech presentation meets standardized requirements.
• Researchers and test developers creating validated speech test lists across languages for clinical trials and epidemiological studies.
  Practical applications include hearing assessments, hearing‑aid and cochlear‑implant evaluations, and cross‑linguistic comparability of speech recognition measures.

Related standards

• ISO 8253-1 (Pure‑tone air and bone conduction audiometry)
• ISO 8253-2 (Sound field audiometry)
• IEC 60645-1 (Electroacoustics - Audiometric equipment)
• ISO/IEC Guide 98-3 (GUM - Uncertainty of measurement)
• IEC 61672-1 (Sound level meters)

Keywords: ISO 8253-3, speech audiometry, audiometric test methods, speech recognition tests, speech test materials, audiometer calibration, competing sound, speech recognition threshold.