Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Science

Program

Health and Rehabilitation Sciences

Supervisor

Allen, Prudence

Abstract

The evaluation of suprathreshold listening abilities in audiological assessment is often minimized despite the valuable insight it produces about auditory discrimination skills. These capabilities can be assessed from psychoacoustic tests. However, measuring these abilities requires a significant amount of time. Therefore, screening tests were developed for frequency discrimination, gap detection, and amplitude modulation tests to identify individuals for whom these skills are most likely to be useful. The purpose of this project was to determine the ability of this screening tool to predict good performers and determine who is likely to have reduced skills and require full threshold assessment. Thirty normal hearing adults were enrolled in the study. The psychoacoustic threshold and screening tests employed the same 3-alternative forced choice procedure. Threshold estimates were obtained and compared to the screening test results. Findings revealed that listeners with psychoacoustic thresholds that fell within normal limits also passed the screening test.

Summary for Lay Audience

The ability to encode acoustic signal features of sound at suprathreshold levels shapes our perception of auditory signals. Suprathreshold abilities to discriminate acoustic signal features of sounds are overlooked in hearing assessments. Audiological assessments rarely evaluate suprathreshold auditory processing abilities beyond speech discrimination measures. Yet the ability to discriminate acoustic signal features of sounds can be impaired in listeners with hearing difficulties. This inability is found in listeners with auditory processing disorders. Professional associations recommend the use of both speech and non-speech-based tests to evaluate discrimination abilities. However, the use of speech-based tests is commonly preferred over non-speech based test. Psychoacoustics is a branch of hearing sciences that measures the physical properties of sounds and the sensations they evoke. Psychoacoustics are non-speech based tests that can assess the suprathreshold abilities to detect and discriminate acoustic features of sounds. However, these psychoacoustic tests can be lengthy, difficult, and require rigorous attention to complete. Therefore, psychoacoustic screeners for frequency discrimination, gap detection, and amplitude modulation have been created to identify individuals with reduced auditory discrimination abilities. It is important to assess auditory discrimination abilities through non-speech based tests since they are not confounded by language factors. The psychoacoustic screeners adhere to strict methodology procedures and principles of psychoacoustics similar to their test versions. The goal of the study was to evaluate the utility of psychoacoustic screening in a normal adult population. Psychoacoustic tests yield threshold estimates of their discrimination abilities. These thresholds were compared to the accuracy of the screeners' ability to assess good performers on these psychoacoustic tests. Findings in the study revealed that listeners with psychoacoustic thresholds that were within normative limits passed all the screeners too. The study demonstrates the possibility of screening for good performers on psychoacoustic thresholds in a normal adult hearing population.

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