Learning effect observed for the speech reception threshold in interrupted noise with normal hearing listeners

Abstract

Traditionally, the speech reception threshold (SRT) for sentences in noise is measured in stationary speech-shaped noise; however, non-stationary masking noises are gradually becoming more common. A previous study by Rhebergen et al. () suggested that a learning effect might be present for the SRT in interrupted noise but not in stationary noise. The current study tested if a stable SRT for female or male speech is reached by determining SRTs in listeners with normal hearing in either stationary or 8-Hz interrupted noise after five replications. Contrary to repeated SRT measurements in stationary noise, a significant improvement was observed for SRTs in interrupted noise with replication. For both speech materials, after five replications, the SRT in interrupted noise improved about 3 to 4 dB in comparison to the first SRT. Stable thresholds seem to be reached after about two replications. This experiment shows that there is a substantial learning effect present in SRT measurements with interrupted noise but not in stationary noise. With non-stationary noise, it is recommended to include a repeated measures design.

• Speech reception
• Threshold
• Speech intelligibility
• Interrupted noise
• Non-stationary noise
• Learning effects

Abbreviations
ANSI	=	American National Standards Institute
HL	=	Hearing level
SII	=	Speech intelligibility index
SNR	=	Signal-to-noise ratio
SRT	=	Speech reception threshold

Abbreviations
ANSI	=	American National Standards Institute
HL	=	Hearing level
SII	=	Speech intelligibility index
SNR	=	Signal-to-noise ratio
SRT	=	Speech reception threshold

Sumario

Tradicionalmente, el umbral de recepción del lenguaje (SRT) para frases en ruido se mide en ruido estacionario con conformación de lenguaje; sin embargo, los ruidos de enmascaramiento no estacionarios se están volviendo gradualmente más comunes. Un estudio previo por Rhebergen y col (2006) sugirió que podría existir un efecto de aprendizaje para el SRT en ruido interrumpido pero no en ruido estacionario. El estudio actual evaluó si se logra un SRT estable con voz masculina o femenina, al determinar el SRT con audición normal tanto en ruido estacionario como en ruido interrumpido de 8 Hz, luego de cinco replicaciones. Al contrario de las mediciones repetidas del SRT en ruido estacionario, se observó una mejoría significativa para los SRT en ruido interrumpido con replicación. Para ambos materiales logoaudiométricos, luego de cinco replicaciones, el SRT en ruido interrumpido mejoró entre 3 y 4 dB en comparación con el primer SRT. Parecen alcanzarse umbrales estables luego de dos replicaciones. Este experimento muestra que existe un sustancial efecto de aprendizaje en las mediciones del SRT con ruido interrumpido pero no en ruido estacionario. Con ruido no estacionario, se recomienda incluir un diseño de mediciones repetidas.