Effects of Stimulus Type on 16-kHz Detection Thresholds.
Level 4 - case-series / case-control
Cross-sectional psychophysical laboratory study in healthy volunteers
PubMed 38178308 · doi:10.1097/AUD.0000000000001446
What was done
Two experiments evaluated how stimulus type affects extended high-frequency detection thresholds. In Experiment 1, audiometric thresholds at 8 and 16 kHz were measured in participants aged 5 to 28 years with normal standard-frequency hearing (250 to 8000 Hz) using steady, pulsed, and frequency-modulated (FM) tones. In Experiment 2, psychophysical testing in participants aged 18 to 28 years evaluated detection thresholds across bandwidth conditions (steady tones, pulsed tones, FM tones, narrow bands of noise, and one-third-octave bands of noise) across center frequencies in one ear to determine the role of the audibility curve slope.
What was found
At 8 kHz, thresholds improved with increasing age and were relatively similar across steady, pulsed, and FM tones. At 16 kHz, thresholds worsened with increasing age, and mean thresholds were approximately 5 dB lower (better sensitivity) for FM tones than for steady or pulsed tones across all age groups. In individual listeners, 16-kHz thresholds were up to 20 dB lower for FM tones than for steady tones. Experiment 2 confirmed that threshold differences between stimulus types were driven by stimulus spectral bandwidth interacting with individual differences in the slope of the audibility curve at extended high frequencies.
Why it matters
Clinical and research protocols often treat pure tones and FM tones as interchangeable, but at extended high frequencies where hearing sensitivity drops off steeply, FM tones can significantly overestimate hearing sensitivity.
Limits
The abstract does not report the total sample size (n) for either experiment. Testing was restricted to individuals aged 5 to 28 with normal conventional-frequency hearing, so results may not generalize to older populations or those with clinical hearing loss.
Cited by
- supports Standard clinical hearing tests evaluate frequencies up to 8 kHz, although human hearing can detect frequencies up to 20,000 Hz.