Age effects in temporal auditory processing: modulation masking release and forward masking effect

ABSTRACT

Purpose

The purpose of this study was to investigate the age-related effects of modulation masking release and forward masking.

Methods

Ten younger (mean age of 18.4) and ten older (mean age of 64.3) adults participated in the study. All participants were native speakers of Brazilian Portuguese with normal hearing. Sentences of the Brazilian version of the Hearing in Noise Test were used to obtain speech recognition thresholds in the presence of steady-state noise and amplitude-modulated noise (10 Hz). To investigate forward masking, auditory thresholds were determined at time intervals of 4, 16, 64, and 128 ms after noise interruption. The Shapiro-Wilk test was applied to evaluate the normality of the results. In the variables in which normality was indicated, the Student’s t-test was applied for the independent samples, and the Mann-Whitney test was applied in cases where normality was not found. A significance level of 5% was adopted for all statistical analyses.

Results

Modulation masking release was present in both groups; however, it was significantly smaller in the elderly group. As for forward masking investigation, higher thresholds were obtained after noise interruption, and improved as the time interval between noise and stimulus presentation increased. Forward masking was higher in the elderly group, whit higher thresholds for the time interval of 128 ms.

Conclusion

An age-related effect was identified on modulation masking release and forward masking.

Keywords:
Hearing; Older listeners; Temporal masking; Speech perception; Noise