Related Experiment Videos
Artifactual responses when recording auditory steady-state responses.
Susan A Small1, David R Stapells
1School of Audiology and Speech Sciences, The University of British Columbia, Vancouver, British Columbia, Canada.
Ear and Hearing
|December 18, 2004
Summary
High-intensity sound stimuli can create false auditory steady-state responses (ASSRs) in hearing-impaired individuals. Careful selection of signal processing parameters is crucial to avoid these artifactual responses, especially with bone-conduction testing.
Area of Science:
- Audiology
- Neuroscience
- Biomedical Engineering
Background:
- Auditory steady-state responses (ASSRs) are objective measures of hearing sensitivity.
- Artifactual responses can mimic true ASSRs, potentially leading to misdiagnosis.
Purpose of the Study:
- To investigate the occurrence of artifactual ASSRs in hearing-impaired participants.
- To determine the influence of stimulus intensity and presentation method (air vs. bone conduction) on artifactual ASSRs.
- To evaluate the impact of analog-to-digital (A/D) conversion rates on artifact generation.
Main Methods:
- ASSRs were recorded using the Rotman MASTER system with varying A/D conversion rates (500, 1000, 1250 Hz).
- Bone-conduction stimuli (20-60 dB HL, 500-4000 Hz) and high-intensity air-conduction stimuli (114-120 dB HL) were used.
- Stimuli polarity was alternated in some conditions to assess response characteristics.
Main Results:
- Artifactual ASSRs were observed with both bone and air conduction, particularly at 500 and 1000 Hz carrier frequencies.
- Higher stimulus intensities (≥40 dB HL for bone conduction, ≥114 dB HL for air conduction) increased the likelihood of artifactual responses.
- Alternating stimulus polarity reduced but did not eliminate artifactual responses in all conditions.
Conclusions:
- High-intensity stimuli can generate spurious ASSRs, especially with bone conduction at 50 dB HL and above.
- Signal conditioning and A/D conversion rates can mitigate some artifactual responses, but others may persist.
- The potential for non-auditory physiological responses contributing to artifactual ASSRs cannot be excluded, impacting clinical interpretation for profound hearing loss assessments.