Effects of speaker age on speech understanding and listening effort in older adults.
Degree GrantorUniversity of Canterbury
Degree NameMaster of Audiology
Purpose: Hearing loss is a prevalent condition among older adults. Structural changes at the auditory periphery, changes in central audition and cognitive function are all known to influence speech understanding in older adults. Biological aging also alters speech and voice characteristics from the age of 50 years. These changes are likely to reduce the clarity of speech signals received by older adults with age-related hearing loss. Recent findings suggest that older adults with hearing loss subjectively find listening to the speech of other older adults more effortful than listening to the speech of younger adults. However, the observations of listener effort were subjective and follow up using an objective measure was recommended. Therefore, the purpose of this study was to determine the influence of speaker age (young versus older) on speech understanding and listener effort in older adults with hearing loss. In addition, the relationships between these parameters, and age and working memory was investigated. It is hypothesised that older adults with hearing loss will recognise less speech, and expend more effort, while listening to speech of an older adult relative to a younger adult. Method: A dual task paradigm was used to measure speech understanding and listening effort in 18 older adult listeners with hearing loss. The primary task involved recognition of target words in sentences containing either high or low contextual cues. The secondary task required listeners to memorise the target words for later recall following a set length of sentences. Listeners performed speech understanding (primary task) under six experimental conditions: For each speaker (i.e., older adult and younger adult) there were 3 listening backgrounds: quiet, and noise at 0 dB SNR and +5 dB SNR. Results: Speech understanding in older adults with hearing loss was significantly improved when the speaker was an older adult, especially in noise. The ability to recall words from memory was also significantly better when the speaker was an older adult. Age was strongly correlated with speech understanding with contributions from hearing loss. Age and working memory had moderate correlations with word recall. Conclusion: The findings provide further evidence that peripheral hearing loss is not the only contributor to speech understanding and word recall ability in older adults. The naturally occurring speech signal also has the potential to influence speech understanding and listening effort in older adults.