Effects of Stimulus Type on 16-kHz Detection Thresholds

Area of Science:

• Audiology
• Hearing Science
• Psychoacoustics

Background:

• Standard audiometric testing often excludes frequencies above 8 kHz.
• Extended high-frequency (EHF) sensitivity may impact natural communication.
• Clinical hearing assessments sometimes use pure and frequency-modulated (FM) tones interchangeably.

Purpose of the Study:

• To investigate how stimulus type affects the measurement of EHF hearing sensitivity.
• To compare EHF threshold estimates using steady, pulsed, and FM tones.
• To evaluate the influence of stimulus bandwidth on EHF detection.

Main Methods:

• Experiment 1: Measured 8- and 16-kHz thresholds using steady, pulsed, and FM tones in participants aged 5-28.
• Experiment 2: Assessed detection of various stimuli (tones, noise bands) across center frequencies using psychophysical procedures.
• Utilized standard audiometric and psychophysical methods to assess hearing sensitivity.

Main Results:

• At 16 kHz, FM tones yielded thresholds approximately 5 dB lower than steady or pulsed tones.
• Thresholds at 16 kHz showed greater variability across stimulus types compared to 8 kHz.
• Individual thresholds at 16 kHz could differ by up to 20 dB between FM and steady tones.

Conclusions:

• The choice of stimulus type significantly impacts EHF threshold measurements, especially at 16 kHz.
• Differences in audibility across frequency, influenced by spectral width, predict threshold variations.
• Evaluating EHF hearing requires careful consideration of stimulus spectral width.