Audiology and Speech Pathology - Research Publications

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    Pre-, Per- and Postoperative Factors Affecting Performance of Postlinguistically Deaf Adults Using Cochlear Implants: A New Conceptual Model over Time
    Lazard, DS ; Vincent, C ; Venail, F ; Van de Heyning, P ; Truy, E ; Sterkers, O ; Skarzynski, PH ; Skarzynski, H ; Schauwers, K ; O'Leary, S ; Mawman, D ; Maat, B ; Kleine-Punte, A ; Huber, AM ; Green, K ; Govaerts, PJ ; Fraysse, B ; Dowell, R ; Dillier, N ; Burke, E ; Beynon, A ; Bergeron, F ; Baskent, D ; Artieres, F ; Blamey, PJ ; Malmierca, MS (PUBLIC LIBRARY SCIENCE, 2012-11-09)
    OBJECTIVE: To test the influence of multiple factors on cochlear implant (CI) speech performance in quiet and in noise for postlinguistically deaf adults, and to design a model of predicted auditory performance with a CI as a function of the significant factors. STUDY DESIGN: Retrospective multi-centre study. METHODS: Data from 2251 patients implanted since 2003 in 15 international centres were collected. Speech scores in quiet and in noise were converted into percentile ranks to remove differences between centres. The influence of 15 pre-, per- and postoperative factors, such as the duration of moderate hearing loss (mHL), the surgical approach (cochleostomy or round window approach), the angle of insertion, the percentage of active electrodes, and the brand of device were tested. The usual factors, duration of profound HL (pHL), age, etiology, duration of CI experience, that are already known to have an influence, were included in the statistical analyses. RESULTS: The significant factors were: the pure tone average threshold of the better ear, the brand of device, the percentage of active electrodes, the use of hearing aids (HAs) during the period of pHL, and the duration of mHL. CONCLUSIONS: A new model was designed showing a decrease of performance that started during the period of mHL, and became faster during the period of pHL. The use of bilateral HAs slowed down the related central reorganization that is the likely cause of the decreased performance.
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    The Effect of Cochlear Implants on Cognitive Function in Older Adults: Initial Baseline and 18-Month Follow Up Results for a Prospective International Longitudinal Study
    Sarant, J ; Harris, D ; Busby, P ; Maruff, P ; Schembri, A ; Dowell, R ; Briggs, R (Frontiers Media, 2019-08-02)
    In older adults, hearing loss is independently associated with an increased rate of cognitive decline, and has been identified to be a modifiable risk factor for dementia. The mechanism underlying the cognitive decline associated with hearing loss is not understood, but it is known that the greater the hearing loss, the faster the rate of decline. It is unknown whether remediation of hearing loss with hearing devices can delay cognitive decline. This 5-year international longitudinal study is investigating the impact of cochlear implants on cognitive function in older people with severe-profound hearing loss, and whether remediation of hearing loss could delay the onset of cognitive impairment. This is the first study to examine the major primary risk factors associated with dementia in the same cohort. Participants were assessed before cochlear implantation and 18 months later using an identical battery including a visually presented cognitive assessment tool (Cogstate battery) that is highly sensitive to small changes in cognition and suitable for use with people with hearing loss. Hearing and speech perception ability were assessed in sound-treated conditions by an audiologist, and a range of questionnaire tools was administered to assess self-perceived ease of listening, quality of life, physical activity, diet, social and emotional loneliness, isolation, anxiety, and depression. A detailed medical health history was taken. Pre-operatively, despite the small initial sample size (n = 59), increased hearing loss and age predicted significantly poorer executive function and visual attention, while tertiary education predicted better executive function. Better self-reported quality of life was correlated with better visual learning performance, and engaging in frequent vigorous physical activity was correlated with poorer visual learning performance. At 18 months, for the first 20 participants, significant benefits of cochlear implants were seen in terms of speech perception, communication ability, and quality of life. Multiple linear regression modeling showed executive function improved significantly for non-tertiary educated males, while cognitive function remained stable for other participants. Further follow-up at 18 month intervals with a larger sample will reveal the effects of cochlear implant intervention on all outcomes, and whether this can delay cognitive decline.
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    Mandarin Lexical Tone Acquisition in Cochlear Implant Users With Prelingual Deafness: A Review
    Tan, J ; Dowell, R ; Vogel, A (AMER SPEECH-LANGUAGE-HEARING ASSOC, 2016-09)
    PURPOSE: The purpose of this review article is to synthesize evidence from the fields of developmental linguistics and cochlear implant technology relevant to the production and perception of Mandarin lexical tone in cochlear implant users with prelingual deafness. The aim of this review was to identify potential factors that determine outcomes for tonal-language speaking cochlear implant users and possible directions for further research. METHOD: A computerized database search of MEDLINE, CINAHL, Academic Search Premier, Web of Science, and Google Scholar was undertaken in June and July 2014. Search terms used were lexical tone AND tonal language, speech development AND/OR speech production AND/OR speech perception AND cochlear implants, and pitch perception AND cochlear implants, anywhere in the title or abstract. CONCLUSION: Despite the demonstrated limitations of pitch perception in cochlear implant users, there is some evidence that typical production and perception of lexical tone is possible by cochlear implant users with prelingual deafness. Further studies are required to determine the factors that contribute to better outcomes to inform rehabilitation processes for cochlear implant users in tonal-language environments.
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    Cantonese Tone Perception for Children Who Use a Hearing Aid and a Cochlear Implant in Opposite Ears
    Mok, M ; Holt, CM ; Lee, KYS ; Dowell, RC ; Vogel, AP (LIPPINCOTT WILLIAMS & WILKINS, 2017)
    OBJECTIVES: The ability to recognize tones is vital for speech perception in tonal languages. Cantonese has six tones, which are differentiated almost exclusively by pitch cues (tones 1 to 6). The differences in pitch contours among the tones are subtle, making Cantonese a challenging language for cochlear implant users. The addition of a hearing aid has been shown to improve speech perception in nontonal languages and in Mandarin Chinese. This study (1) investigates the Cantonese tone perception ability of children who use a cochlear implant and a hearing aid in opposite ears; (2) evaluates the effect of varying pitch height and pitch contour cues on Cantonese tone perception for these children; and (3) compares the Cantonese tone perception ability for using a hearing aid and a cochlear implant together versus an implant alone. DESIGN: Eight native Cantonese speaking children using a cochlear implant and a hearing aid in opposite ears were assessed for tone perception and word identification. The tone perception test involved discriminating and ranking tone pairs from natural and artificially manipulated Cantonese tones with various pitch heights and/or pitch contours. The word identification test involved identifying Cantonese words in a four-alternative forced-choice task. All tests were performed in two device conditions: (1) cochlear implant and hearing aid together and (2) implant alone. RESULTS: Seven of the 8 subjects performed significantly above chance in both tests using the cochlear implant alone. Results showed that both pitch height and/or pitch direction were important perceptual cues for implant users. Perception for some tones was improved by increasing the pitch height differences between the tones. The ability to discriminate and rank the tone 2/tone 5 contrast and the tone 4/tone 6 contrast was poor, as the tones in these contrasts are similar in pitch contours and onset frequencies. No significant improvement was observed after artificially increasing the pitch offset differences between the tones in the tone 2/tone 5 and the tone 4/tone 6 contrasts. Tone perception results were significantly better with the addition of the hearing aid in the nonimplanted ear compared with using the implant alone; however, word identification results were not significantly different between using the implant alone and using both the hearing aid and the implant together. None of the subjects performed worse in tone perception or in word identification when the hearing aid was added. CONCLUSIONS: Reduced ability to perceive pitch contour cues, even when artificially exaggerated, may explain some of the difficulties in Cantonese word recognition for implant users. The addition of a contralateral hearing aid could be beneficial for Cantonese tone perception for some individuals with a unilateral implant. The results encouraged Cantonese speakers to trial a hearing aid in the nonimplanted ear when using a cochlear implant.
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    Perception of Cantonese Lexical Tones by Pediatric Cochlear Implant Users
    Holt, CM ; Lee, KYS ; Dowell, RC ; Vogel, AP (AMER SPEECH-LANGUAGE-HEARING ASSOC, 2018-01)
    PURPOSE: The purpose of this study is to assess Cantonese word recognition and the discrimination of Cantonese tones with manipulated contours by child and adolescent cochlear implant (CI) users and a group of peers with normal hearing (NH). It was hypothesized that the CI users would perform more poorly than their counterparts with NH in both tasks and that CI users implanted before 2 years of age would perform better than those implanted after 2 years. METHOD: Forty-one participants were recruited from hospitals, schools, and kindergartens in Hong Kong: Ten CI users implanted at or before 2 years of age ("early" CI group), 13 CI users implanted after 2 years of age ("late" CI group), and 18 individuals with NH. The mean age at implantation of the early CI group was 1.5 years (SD = 0.3), and for the late CI group, it was 4.3 years (SD = 2.1). Participants were a mean of 13.3 years of age (SD = 3.7) at time of testing. Participants completed a Cantonese word recognition test and a discrimination task using Cantonese tones with modified fundamental frequency trajectories. RESULTS: Both CI user groups obtained significantly lower scores than the group with NH on the word recognition test. Mean percent correct scores for the word recognition test were 79% for the early CI group, 69% for the late CI group, and 97% for the group with NH. The group with NH consistently achieved higher scores than the CI user groups when discriminating manipulated Cantonese tones. Increasing the acoustic difference between tones improved discrimination performance for CI users for level tone contrasts only. CI users implanted at or before 2 years of age obtained higher scores than those implanted later. CONCLUSIONS: The results of this study add further evidence that children using CIs do not perform as well as peers in perceiving Cantonese tones. Modification of tones to increase pitch range did not consistently improve the ability of children with implants to perceive the difference between tones. Further research is required to fully assess potential benefits of early implantation for speakers of tonal languages. SUPPLEMENTAL MATERIALS: https://doi.org/10.23641/asha.5782209.
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    Speech Detection in Noise for Young Bilaterally Implanted Children: Is There Evidence of Binaural Benefit Over the Shadowed Ear Alone?
    Galvin, KL ; Dowell, RC ; van Hoesel, RJ ; Mok, M (LIPPINCOTT WILLIAMS & WILKINS, 2017)
    OBJECTIVES: To measure binaural benefit over the shadowed ear alone for young bilateral cochlear implant (CI) users. It was hypothesized that children who received bilateral CIs at a young age (<4 years), and had significant bilateral experience, would demonstrate lower detection thresholds for speech sounds in background noise in the bilateral CI over the unilateral CI condition when the added CI was ipsilateral to the noise source. DESIGN: Children receiving bilateral CIs at the Eye and Ear Hospital Clinic in Melbourne were invited to participate in a wider research project evaluating outcomes; those participating in the wider project who were bilaterally implanted by 4 years and were approximately 2 years postoperative were included in the present study. For 20 participants, detection signal to noise ratios (SNRs) were measured for speech presented from in front and noise from 90° in at least 3 of 4 device/noise conditions, namely left CI/noise right and right CI/noise left, plus bilateral CIs/noise right and bilateral CIs/noise left. RESULTS: As some participants could only complete testing in 3 conditions within the 1 test block, the unilateral versus bilateral comparison was performed for 1 CI (i.e., 1 noise direction) for 15 participants and for both CIs (i.e., noise left and noise right) for 5 participants. Group analysis indicated no significant difference in detection SNR between the unilateral and bilateral CI conditions when adding the left CI or right CI (for the overall group) or when adding the first or second CI (for the 15 participants with sequential bilateral CIs). Separate analyses indicated no significant difference in detection SNR between the unilateral and bilateral CI conditions for the majority of individuals; this occurred irrespective of whether the analysis indicated that the CI added in the bilateral condition was poorer-performing, better-performing, or not significantly different compared with the other CI. Four individuals demonstrated a significant improvement in the bilateral condition when the CI added in the bilateral condition was a better-performing (n = 1), poorer-performing (n = 2), or not significantly different CI (n = 1). There was no relationship between the detection SNR difference between each CI and the detection SNR difference between the unilateral and bilateral conditions. CONCLUSIONS: The hypothesis of a lower detection SNR in the bilateral condition was not supported by the group results or by the results for the majority of individuals. For the 4 participants who did demonstrate benefit over the shadowed ear alone, that benefit cannot be separated from the potential benefit gained as a result of the CI added in the bilateral condition being the better-performing CI for 1 of the 4. Variation in outcomes could not be related to demographic factors for this group, which was relatively homogeneous for age at bilateral CI and experience; an older, more experienced group may demonstrate greater binaural benefit in these conditions. These results can be used during counseling for families regarding postoperative expectations for young children, especially in the first 2 years.
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    Talking to Toddlers: Drawing on Mothers' Perceptions of Using Wearable and Mobile Technology in the Home
    Choo, D ; Dettman, S ; Dowell, R ; Cowan, R ; Ryan, A ; Schaper, LK ; Whetton, S (IOS PRESS, 2017)
    BACKGROUND: Mother-child interactions often give rise to opportunities for early language learning in the context of everyday life. Persuasive technology has the potential to influence maternal language behaviours in the home and promote mothers' active engagement in the development of their children's communication skills. AIM: This paper explored maternal perceptions regarding the use of a language tracking wearable (Language Environment Analysis; LENA) device and a parent education smartphone application in an 8-week trial with their young children. METHODS: Mother/child dyads were enrolled in a feasibility trial designed to obtain objective auditory and linguistic data from each child's naturalistic settings (Control Condition), provide feedback to mothers about their child's home language environment (LENA Feedback Condition), and to explore effectiveness of an app designed to promote meaningful parent/child interactions during daily routines (LENA Feedback and App Condition). RESULTS AND DISCUSSION: The majority of mothers (80%) who participated in the trial reported a preference for using the mobile app and/or LENA technology again. Maternal responses during this pilot informed the design of an ongoing, prospective language intervention study for parents and their young children with significant hearing loss.
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    A retrospective study of preterm children using cochlear implants
    Oh, SJ ; Dettman, SJ ; Dowell, RC ( 2013)
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    Communication Outcomes for Groups of Children Using Cochlear Implants Enrolled in Auditory-Verbal, Aural-Oral, and Bilingual-Bicultural Early Intervention Programs
    Dettman, S ; Wall, E ; Constantinescu, G ; Dowell, R (LIPPINCOTT WILLIAMS & WILKINS, 2013-04)
    OBJECTIVE: The relative impact of early intervention approach on speech perception and language skills was examined in these 3 well-matched groups of children using cochlear implants. STUDY DESIGN: Eight children from an auditory verbal intervention program were identified. From a pediatric database, researchers blind to the outcome data, identified 23 children from auditory oral programs and 8 children from bilingual-bicultural programs with the same inclusion criteria and equivalent demographic factors. PATIENTS: All child participants were male, had congenital profound hearing loss (pure tone average >80 dBHL), no additional disabilities, were within the normal IQ range, were monolingual English speakers, had no unusual findings on computed tomography/magnetic resonance imaging, and received hearing aids and cochlear implants at a similar age and before 4 years of age. MAIN OUTCOME MEASURES: Open-set speech perception (consonant-nucleus-consonant [CNC] words and Bamford-Kowal-Bench [BKB] sentences) and the Peabody Picture Vocabulary Test (PPVT) were administered. RESULTS: The mean age at cochlear implant was 1.7 years (range, 0.8-3.9; SD, 0.7), mean test age was 5.4 years (range, 2.5-10.1; SD, 1.7), and mean device experience was 3.7 years (range, 0.7-7.9; SD, 1.8). Results indicate mean CNC scores of 60%, 43%, and 24% and BKB scores of 77%, 77%, and 56% for the auditory-verbal (AV), aural-oral (AO), and bilingual-bicultural (BB) groups, respectively. The mean PPVT delay was 13, 19, and 26 months for AV, AO, and BB groups, respectively. CONCLUSION: Despite equivalent child demographic characteristics at the outset of this study, by 3 years postimplant, there were significant differences in AV, AO, and BB groups. Results support consistent emphasis on oral/aural input to achieve optimum spoken communication outcomes for children using cochlear implants.
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    Cochlear Implants in Forty-Eight Children with Cochlear and/or Vestibular Abnormality
    Dettman, S ; Sadeghi-Barzalighi, A ; Ambett, R ; Dowell, R ; Trotter, M ; Briggs, R (KARGER, 2011)
    CT and MRI scans for 48 children with cochlear and/or vestibular abnormality were classified in decreasing severity; common cavity, Mondini plus enlarged vestibular aqueduct, Mondini dysplasia alone and enlarged vestibular aqueduct alone. No significant relationship between degree of cochlea abnormality and surgical issues (cerebrospinal fluid gusher, depth of insertion, number of electrodes) or speech perception/language outcomes was found. A significant relationship was observed between cerebrospinal fluid gusher and partial electrode insertion, fewer active electrodes and poorer sentence understanding. Optimum language outcomes were associated with younger age at implant.