Effects of Intra-Talker Differences on Speech Understanding in Noise by Younger and Older Adults

Abstract

The purpose of the study was to investigate the effects on intelligibility when listening to a talker whoproduced speech while being exposed to different types and levels of noise. In addition, we alsoinvestigated how the word identification performance of younger and older listeners for these conditionswas affected in different listening environments. A male young adult talker recorded the SPIN-R test whilelistening to different types and levels of noise and following different speaking instructions. Younger andolder adults with clinically normal hearing from 250 to 3000 Hz were tested on these recordings in threesignal-to-noise ratios. Significant word recognition differences were found between the standard talkingcondition and loud speech recorded in quiet, despite the fact that all sentences were equated for overallintensity. Older listeners found speech produced in noise beneficial when there was more backgroundnoise, but younger listeners did not. Clear speech in this study did not produce any benefit for listenersrelative to the baseline condition. Acoustic analyses showed that intensity fluctuations within the sentencesled to a higher intensity for target words in the loud speech condition relative to all other conditions, whiletarget words in clear speech had a lower fundamental frequency compared to other conditions. Listenerperformance may change on a test of speech intelligibility when speech is produced under moreecologically valid conditions; however, these effects are small and may be more apparent in older adultsand when task difficulty is greater due to lack of contextual support and higher levels of background noise.