Audiology and Speech Pathology - Theses
Permanent URI for this collection
Search Results
1 - 2 of 2
-
ItemThe processing of Mandarin-accented English by older hearing-impaired adults and their perceptual adaptation to the accent( 2023-06)ABSTRACT Older, hearing-impaired (OHI) adults have proportionately more trouble hearing speech in adverse listening situations than normally hearing (NH) listeners. When the speech signal is degraded through the presence of background noise, fast speech, or is otherwise unclear, OHI adults have more trouble with speech recognition (Humes and Dubno, 2010) and expend more cognitive resources in working out what has been said than do NH listeners (Tun, McCoy & Wingfield, 2009). This study investigated whether OHI listeners are likewise disproportionately disadvantaged by an unfamiliar accent, namely Mandarin Accented English (MAE), and whether these listeners are able to adapt to the systematicities of the accent. 27 OHI, 27 ONH and 29 YNH listeners were recruited. Cross modal fragment priming (CMFP) was utilised in Experiment 1 to measure the effect of a phonological error often made by speakers of MAE, the lack of reduction of the vowel in unstressed iambic words. Response times and accuracy were compared between the listener groups, between Australian English (AusE) and MAE tokens and between matching and mismatching primes and targets. Talker-independent adaptation was evaluated in a second experiment through an exposure training study design. Listeners were trained either by four MAE talkers or four AusE talkers before listening to sentences presented by a novel MAE talker. Speech recognition was compared between the listener groups and the training accents. In experiment one, the CMFP study, all listener groups were slower and less accurate in their responses to MAE. While the YNH group was faster to respond to all tokens (AusE and MAE) than both the OHI and the ONH groups, they were only significantly more accurate in responding to the AusE tokens, indicating that they too, found MAE speech recognition difficult. The YNH listeners demonstrated significantly faster responses than both older groups in the most cognitively challenging conditions where prime and target did not match. In experiment two, the adaption study, all three groups trained by the MAE talkers showed higher odds of speech recognition than listeners trained by AusE talkers, showing the benefit of exposure to the accent for MAE recognition. The OHI listeners adapted to MAE to the same degree as the NH listeners despite returning lower overall odds of recognising MAE speech. While OHI listeners with mild to moderate hearing loss showed similar accuracy in responses to MAE words and fragment tokens as did the normally hearing listeners, both older listener groups took substantially longer to respond to these tokens, especially in the more cognitively taxing mismatching conditions. This result indicates that older listeners had greater difficulty processing the speech tokens which, however, was not always reflected in their recognition results. In addition, OHI listeners were able to benefit as much from their brief exposure to MAE as did the NH groups. This result suggests that OHI with mild-moderate hearing loss have access to and can exploit the information present in a relatively brief sample of accented speech and generalise this learning to a novel MAE talker. This potential to adapt to the accent of an FAS talker will be important for ensuring smooth communication interactions, particularly when the communication partner is committed to reducing the barriers to communication by, for example, reducing their rate of speech. This study has utilised theories, study designs and methodological techniques developed in the field of psycholinguistics and in particular, has demonstrated the benefit of using RT measurements to learn more about the processing difficulty of FAS as experienced by OHI adults. The study has also indicated the potential for psycholinguistic theories of speech processing to be expanded by examining the language processing of older listeners with an impaired auditory system.
-
ItemThe Effect of Higher Order Listening Function and Hearing Loss on Cognition in Older Adults( 2020)INTRODUCTION: Previous research has identified a relationship between hearing loss and cognitive impairment/dementia in older adults, however this research has primarily focused on measures of sensorineural hearing loss (SNHL). Central Auditory Processing (CAP), an ability which decreases with increasing age, is recognised as important for understanding speech in background noise, but is not routinely considered in audiological assessment or hearing-cognition research. Yet, some studies have provided evidence that poorer performance on some measures of CAP ability significantly relate to reduced cognitive function and/or increased likelihood of dementia diagnosis. Although there is no known treatment for cognitive impairment, hearing impairment is to some extent treatable with hearing aids (HAs). OBJECTIVES: This study aimed to examine the relationship between hearing impairment and cognitive impairment by assessing both peripheral hearing loss and CAP ability. Additionally, this research aimed to investigate how hearing, cognition and personal factors influence HA outcomes (uptake/use/benefit) in older adults. DESIGN: Experimental study design with 85 older adults between the ages of 60.33 and 80.08 (m =70.23, SD = 5.17). SNHL was assessed using Pure Tone Audiometry (PTA), the Listening in Spatialised noise-Sentences (LiSN-S) test and Dichotic Digits Test. Cognition was measured using the Cogstate Brief Battery. Personal factors were recorded from participant’s answers on a series of take-home questionnaires. Hearing aid benefit and use was subjectively reported at three- and six-months post HA fitting. RESULTS: Results for three of the four LiSN-S conditions shared a significant correlation with at least one cognitive measure, and SNHL was also significantly related to two cognitive domains (attention and executive function) in this cohort. Those who decided to use HAs had significantly poorer hearing as measured by both PTA and the LiSN-S test, and those with poorer hearing reported greater HA benefit. Lastly, stronger psychomotor function was associated with greater reported use of HAs at three- and six-months post HA fitting. Greater family interaction and attention scores also were associated with greater HA use at three- and six-months post fitting respectively. IMPLICATIONS: The older hearing-impaired patient may present with a combination of hearing loss, decreased auditory processing ability and impaired cognitive ability. It may be prudent to consider the presence and possible interactions of multiple health conditions as well as psychosocial factors when determining the appropriate management pathway for and expectations of the patient. Future research should investigate longitudinal cognitive implications for patients presenting with a SP deficit. Also, for older adults presenting with a SP deficit, the benefits of early referral for cognitive assessment should be considered. Moreover, a combination of hearing, cognitive and psychosocial factors impact HA outcomes in older Australians. These factors should be considered in audiological rehabilitation to best maximise patient HA outcomes, and further research should consider the long-term clinical implications HA fitting has on natural cognitive decline in the elderly.