The Audible Contrast Threshold (ACT) test: A clinical spectro-temporal modulation detection test.
Johannes Zaar1, Lisbeth Birkelund Simonsen2, Raul Sanchez-Lopez3
1Eriksholm Research Centre, Rørtangvej 20, 3070 Snekkersten, Denmark; Hearing Systems Section, Department of Health Technology, Technical University of Denmark, Ørsteds Plads, Building 352, 2800 Kgs. Lyngby, Denmark.
Hearing Research
|September 7, 2024
Summary
A new Audible Contrast Threshold (ACT™) test offers a quick and reliable measure of spectro-temporal modulation (STM) sensitivity for hearing-impaired individuals. This clinically viable test provides valuable beyond-audiogram insights, aiding in better hearing assessments.
Area of Science:
- Audiology and Hearing Science
- Auditory Perception
- Signal Processing in Hearing
Background:
- Hearing-impaired listeners' speech-in-noise ability correlates with spectro-temporal modulation (STM) detection.
- Existing STM tests lack clinical viability due to duration, equipment, and standardization issues.
- There is a need for a quick, reliable clinical tool for assessing STM sensitivity.
Purpose of the Study:
- To introduce and validate a clinically viable STM test, the Audible Contrast Threshold (ACT™) test.
- To establish normative data and a standardized scale (dB nCL) for the ACT test.
- To assess the test-retest reliability and agreement with established STM paradigms.
Main Methods:
- Developed an experimenter-controlled STM measurement paradigm with audibility-corrected noise and a Hughson-Westlake procedure.
- Optimized a stimulation paradigm using 1-second windowed noise and logistic function fitting.
- Collected data from hearing-impaired and normal-hearing participants using various transducers to establish normative data and the normalized Contrast Level (nCL) scale.
Main Results:
- The optimized ACT test demonstrated excellent test-retest reliability and good agreement with established laboratory STM tests.
- Normative data were obtained from normal-hearing participants, defining the normalized Contrast Level (nCL) scale.
- The ACT test is quick, simple, and can be administered immediately after an audiogram using existing equipment.
Conclusions:
- The ACT test is a reliable, quick, and clinically viable tool for assessing STM sensitivity in hearing-impaired individuals.
- The ACT test provides valuable beyond-audiogram information, complementing traditional hearing assessments.
- The normalized Contrast Level (nCL) offers a standardized measure of audible contrast loss.
