pure-tone average
A single numerical value, expressed in dB HL, representing the mean hearing threshold across a specified set of frequencies (typically 500 Hz, 1 kHz, and 2 kHz, or including 4 kHz), used to summarise overall hearing sensitivity.
Full Definition
The pure-tone average (PTA) is the arithmetic mean of pure-tone air-conduction thresholds at two, three, or four frequencies, depending on the clinical or medicolegal context. The three-frequency PTA (500 Hz, 1 kHz, 2 kHz) is standard in most clinical settings, while the four-frequency PTA adds 4 kHz and is required in some occupational and compensation frameworks. PTA is also used to predict speech recognition ability and to classify degree of hearing loss. Editors should verify which frequency set was used when a PTA figure is quoted and flag any inconsistency between the stated frequencies and the calculated value.
Usage
Usage note: Always specify which frequencies were averaged (e.g., '3-frequency PTA at 0.5, 1, 2 kHz'). Do not conflate PTA with speech reception threshold, which is a measure of speech, not tone detection.
In Context
- "The three-frequency pure-tone average was 48 dB HL, placing the patient in the moderate category." — Audiological assessment report
- "For compensation purposes, a four-frequency PTA was calculated at 500 Hz, 1 kHz, 2 kHz, and 3 kHz." — Occupational health medicolegal report