Acceptable Noise Level: Effect of Number of Talkers in Native and Non-Native Speech Babbles in Older Adults with Hearing Impairment

Abstract

Acceptable noise level is the amount of background noise that listeners are willing to accept when listening to speech signal. It is especially used to predict the outcome of a hearing aid. The most common noise present in our environment is speech babble which varies from time to time between known and unknown languages. Thus, the present study aimed to study the effect of number of talkers in native and non-native speech babble on the acceptable noise level in older adults with hearing impairment. A group of 22 older adults were taken within the age group of 55 to 70 years. ANL was estimated using target Kannada sentences in the presence of 2- talker, 4-talker, 8- talker, 10-talker and 12-talker Kannada and English babbles. The results showed that 4-talker Kannada babble resulted in best ANL score. In non-native English language, the best score was found in 2-talker babble. The reason for best score in Kannada language could be due to the informational masking in 2-talker babble. The best score in English language was 2-talker babble and the reason was that the low proficiency in unknown language which tends to suppress the masker effect. In the presence of both Kannada and English babbles, ANL was poorer as the number of talkers in the babble increased. It can be concluded from the results of the current study that there is an effect of number of talkers in babble on ANL and 4- talker babble resulted in the best ANL in the native language. In the presence of non-native language babble, ANL is the best with 2-talker babble indicating that information masking is predominant in the presence of native language. This suggests a possible influence of language of the background speech babble on ANL.