The general goal of the research is to identify factors that contribute to the speech recognition problems of elderly listeners and to evaluate methods used to enhance speech recognition among elderly hearing-impaired listeners. The research project comprises four stages of investigation, each incorporating speech and psychoacoustic measures obtained from the same listeners. The principal focus of the investigation for each stage corresponds respectively to the specific aims: 1) to examine the impact of low pass noise (LPN) on speech perception in elderly listeners with normal hearings and with hearing loss; 2) to determine if speech perception is improved in elderly listeners by artificially altering the consonant to novel ratio (CVR) or through hearing aid amplification in the presence of LPN; 3) to determine if consonant audibility is a factor contributing to speech enhancement; and 4) to determine if upward spread of masking empirical data collected from each stage will be used to establish stimulus parameters and interpret new data in each subsequent stage. For each stage, the extent to which speech and psychoacoustic measures are correlated as a function of hearing status will be determined. A practical goal is to utilize the findings in this study to better understanding the extent that advanced hearing aid technologies improve speech understanding over more traditional hearing aids. This, in turn, will provide elderly hearing-impaired individuals with additional objective information that can help them make an informed decision regarding their hearing aid choice.
| Dorsey, Charles H; Cousin, Carolyn E; Lewis, Fred A et al. (2002) Ultrastructure of the Schistosoma mansoni cercaria. Micron 33:279-323 |
