Hearing impairment (HI) affects a large proportion of older adults: 25% of 65-74 year olds, and 50% of people 75 and older have a HI that is sufficiently severe to be disabling [36,42]. The primary complaint of individuals with HI is difficulty understanding speech. Suboptimal speech communication by people with HI is a likely reason why they suffer from broader behavioral and physical health problems [35,53]. Understanding the factors that affect speech perception by people with HI, and finding methods to overcome the speech perception difficulties that these individuals face, is of great societal importance. Because of changing US demographics, communication between older individuals with HI and younger individuals?including those in caregiving and service-delivery roles?is increasingly likely to be between individuals of different races and ethnicities [44,54]. This presents a potential unique problem to individuals with HI. Research has shown that a talker's speech can become less intelligible to normal hearing (NH) individuals when they become aware of a talker's race or ethnicity by seeing a picture of the talker [6,37,48]. Given ongoing demographic changes, these findings have potentially profound implications for our understanding of speech perception by older adults with HI, as their communication with younger individuals is likely to be across lines of race and ethnicity. This may provide an additional challenge to speech perception beyond the challenge posed by the sensory loss itself. The proposed project seeks to remove two barriers to conducting large-scale studies of effects of race and ethnicity on speech perception by older adults with HI. One barrier is that there are no existing audiovisual corpora of speech stimuli that are produced by ethnically and racially diverse individuals.
In specific aim 1, we will build a new corpus of audiovisual speech stimuli produced by individuals from diverse races and ethnicities. This corpus will include both standard-of-care sentences used in research on HI , and a new set of sentence materials designed specifically for this project. This corpus will be made available to the public at the conclusion of funding. The second barrier is that the previous studies have not determined the specific mechanism that explains why talker race and ethnicity affect speech intelligibility.
In specific aim 2, we will use stimuli from specific aim 1 in a series of intelligibility experiments with younger listeners with NH, older listeners with NH, and older listeners with HI, using both behavioral and eye-tracking responses. We will also collect information on individuals' attitudes toward individuals of different races and ethnicities, as well as the ethnic and racial diversity in their peer groups. Results from this specific aim will help us better understand the mechanisms that underlie effects of race and ethnicity on speech intelligibility, and whether the speech perception of older adults with HI is disproportionately poorer in interactions with racially and ethnically diverse interlocutors. Given ongoing demographic changes and the high incidence of hearing impairment, these results will be of high
Recent research has shown that speech intelligibility can change when a listener becomes aware of a talker's race and ethnicity. This project will build a corpus of audiovisual speech stimuli produced by ethnically and racially diverse talkers, determine the locus of effects of talker race and ethnicity effects on speech intelligibility, and determine the extent to which talker race and ethnicity affect speech perception by older listeners with hearing impairment (HI). Given the large percentage of the population that has HI (50% of people over 75), and the large and growing percentage of the US population of the US that is Latinx (~17%) and non-white (~37%), these findings are of great public health relevance.