The aim of this research training application is to examine the difficulty experienced by older individuals and hearing impaired individuals when trying to recognize speech in background noise. To accomplish this, two areas will be examined: the effects of aging and hearing loss on speech recognition in noises varying in temporal complexity, and the influence of temporal processing on these effects. Younger normal-hearing listeners recognize more speech in an amplitude-modulated background noise than in an unmodulated noise; however, older and hearing-impaired listeners are not as able to use background noise modulation to their advantage. Unfortunately, a clear understanding of the influences of age and hearing loss on this diminished ability has yet to be obtained. The goal of this project is to come to a better understanding of the influences of age and hearing loss on a person's ability to recognize speech in both amplitude-modulated and unmodulated noises. To accomplish this, older and younger listeners with normal hearing and hearing impairment will be tested. Experimental tasks will include speech recognition testing in five different background noises of increasing temporal complexity. Additionally, to investigate the underlying processes that may produce the effects of age and hearing impairment, three stages of the temporal window model of temporal resolution will also be tested: auditory filter shapes, compressive nonlinearity (i.e., growth of forward masking), and temporal window shapes.
