An Evaluation of the Audible Contrast Threshold (ACT) Test to Predict Speech Perception in Noise Ability

Abstract

Background: The standard audiological protocol is inadequate for the determination of the ability to perceive speech in the presence of background noise. Even individuals with normal pure-tone thresholds may report speech perception in noise difficulties. Recent research has demonstrated that the Audible Contrast Threshold (ACT) test may be used to infer speech perception in noise ability for hearing impaired individuals who wear hearing aids. The ACT may also be a reasonable measure of speech perception in noise ability for individuals with normal pure-tone thresholds.

Purpose: The purpose of this study was to determine the relationship between ACT test results and Hearing in Noise Test (HINT) thresholds. A strong relationship between variables would indicate that the ACT test is a reasonable predictor of speech perception in noise ability for individuals with normal pure-tone thresholds or “normal hearing.”

Research Design: ACT test and HINT thresholds were determined under headphones. The maskers used with the HINT included steady-state speech-shaped noise, four-talker babble, and twenty-talker babble.

Study Sample: Forty-one young, native English-speaking females with pure-tone thresholds less than or equal to 25 dB HL participated in this study. The average age of the participants was 21.3 years (standard deviation = 2.04).

Data Collection and Analysis: Spearman rho correlation coefficients were used to quantify the relationships between all measures.

Results: Weak and statistically non-significant relationships were found between ACT thresholds and the HINT thresholds for each of the masker conditions (r < 0.30, p > 0.05).

Conclusion: These results suggest that the ACT test is not a good predictor of speech perception in noise ability for individuals with pure-tone thresholds less than or equal to 25 dB HL. Speech perception in noise ability must be measured directly and not inferred from ACT thresholds.