Audiology and Speech Pathology - Research Publications

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    The narrow window: early cochlear implant use
    Dettman, SJD ; Leigh, JRL ; Dowell, RCD ; Pinder, DP ; Briggs, RJB ( 2007)
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    Communication development in children who receive the cochlear implant younger than 12 months: risks versus benefits.
    Dettman, SJ ; Pinder, D ; Briggs, RJS ; Dowell, RC ; Leigh, JR ( 2007-04)
    BACKGROUND: The advent of universal neonatal hearing screening in some countries and the availability of screening programs for at-risk infants in other countries has facilitated earlier referral, diagnosis, and intervention for infants with hearing loss. Improvements in device technology, two decades of pediatric clinical experience, a growing recognition of the efficacy of cochlear implants for young children, and the recent change in the U.S. Food and Drug Administration's age criteria to include children as young as 12 mo has led to increasing numbers of young children receiving cochlear implants. Evidence to support provision for infants younger than 12 mo is extrapolated from physiological studies, studies of children using hearing aids, and studies of children older than 12 mo of age with implants. To date, however, there are few published research findings regarding communication development in children between 6 and 12 mo of age who receive implants. The current study hypothesized that earlier implantation would lead to increased rates of language acquisition as the children were still in the critical period for their development. METHOD: A retrospective review was completed for 19 infants (mean age at implantation, 0.88 yr; range, 0.61-1.07, SD 0.15) and 87 toddlers (mean age at implantation, 1.60 yr; range, 1.13-2.00, SD 0.24) who received the multichannel implant in Melbourne, Australia. Preimplantation audiological assessments for these children included aided and unaided audiograms, auditory brain stem response, auditory steady state response (ASSR), and otoacoustic emission and indicated profound to total bilateral hearing loss in all cases. Communication assessment included completion of the Rossetti Infant-Toddler Language Scale and educational psychologists' cognitive and motor assessment. Computed tomography scan, magnetic resonance imaging, and surgical records for all cases were reviewed. Postimplantation language assessments were reported in terms of the rate of growth over time on the language comprehension and language expression subscales of the Rossetti Infant-Toddler Language Scale. RESULTS: Results demonstrated that cochlear implantation may be performed safely in very young children with excellent language outcomes. The mean rates of receptive (1.12) and expressive (1.01) language growth for children receiving implants before the age of 12 mo were significantly greater than the rates achieved by children receiving implants between 12 and 24 mo, and matched growth rates achieved by normally hearing peers. These preliminary results support the provision of cochlear implants for children younger than 12 mo of age within experienced pediatric implantation centers.
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    Speech perception results for children using cochlear implants who have additional special needs
    Dettman, SJ ; Fiket, H ; Dowell, RC ; Charlton, M ; Williams, SS ; Tomov, AM ; Barker, EJ (ALEXANDER GRAHAM BELL ASSOC FOR THE DEAF, 2004)
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    Components of a rehabilitation programme for young children using the Multichannel cochlear implant
    DETTMAN, S ; Barker, E ; Rance, G ; Dowell, R ; Galvin, K ; Sarant, J ; Cowan, R ; Skok, M ; Larratt, M ; Clark, G ; Allum, DJ (John Wiley & sons, Inc., 2006)
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    Speech perception outcomes in older children who use multichannel cochlear implants: Older is not always poorer
    Dowell, RC ; Dettman, SJ ; Hill, K ; Winton, E ; Barker, EJ ; Clark, GM (SAGE Publications, 2002-01-01)
    Speech perception outcomes for early-deafened children who undergo implantation as teenagers or young adults are generally reported to be poorer than results for young children. It is important to provide appropriate expectations when counseling adolescents and their families to help them make an informed choice regarding cochlear implant surgery. The considerable variation of results in this group makes this process more difficult. This study considered a number of factors in a group of 25 children who underwent implantation in Melbourne between the ages of 8 and 18 years. Each subject completed open-set speech perception testing with Bamford-Kowal-Bench sentences before and after implantation and preoperative language testing with the Peabody Picture Vocabulary Test. Data were collected regarding the type of hearing loss, age at implantation, age at hearing aid fitting, audiometric details, and preoperative and postoperative communication mode. Results were submitted to a stepwise multiple linear regression analysis with postoperative open-set sentence scores as the dependent variables. The analysis suggested that 3 factors have a significant predictive value for speech perception after implantation: preoperative open-set sentence score, duration of profound hearing loss, and equivalent language age. These 3 factors accounted for 66% of the variance in this group. The results of this study suggest that children who have useful speech perception before implantation, and higher age-equivalent scores on language measures, would be expected to do well with a cochlear implant. Consistent with other studies, a shorter duration of profound hearing loss is also advantageous. The mean sentence score for this group, 47%, was not significantly different from the mean result across all children in the Melbourne program.
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    Speech perception in children using cochlear implants: prediction of long-term outcomes
    Dowell, RC ; Dettman, SJ ; Blamey, PJ ; Barker, EJ ; Clark, GM (Informa UK Limited, 2002-03)
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    Speech detection and localization results and clinical outcomes for children receiving sequential bilateral cochlear implants before four years of age
    Galvin, KL ; Mok, M ; Dowell, RC ; Briggs, RJ (INFORMA HEALTHCARE, 2008)
    The aim of this study was to describe the adaptation to bilateral cochlear implant use and the perceptual benefits demonstrated by 10 children who were successful users of a first implant when a second was received before four years of age. Although one subject rejected the second implant at switch-on, the nine subjects who accepted the device adapted easily to bilateral implant use and developed useful listening skills with the second implant. Tests of localization (left versus right) and speech detection in noise were administered in the unilateral and bilateral conditions, usually after six months experience. All subjects demonstrated some bilateral benefit on speech detection testing (mostly due to a headshadow effect), and the majority localized left versus right. Results suggested that outcomes may be negatively impacted by increased age at the time of second implant switch-on. The majority of the subjects adapted well to bilateral implant use within six months and demonstrated some perceptual benefit and, according to subjective parent reports, improved daily functioning; however, device rejection must be discussed pre-operatively as a possibility.
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    Perceptual benefit and functional outcomes for children using sequential bilateral cochlear implants
    Galvin, KL ; Mok, M ; Dowell, RC (LIPPINCOTT WILLIAMS & WILKINS, 2007-08)
    OBJECTIVE: To evaluate the additional perceptual benefit provided to children through the use of two cochlear implants in comparison to one after 6 to 13 mo experience with sequential bilateral implants. DESIGN: A second cochlear implant was received by 11 children. The principal selection criteria were being age 4 to 15 yr with a bilateral profound hearing loss and being a consistent user of a first implant with a commitment to use of a second implant. Horizontal localization was assessed by using pink noise bursts presented from a 180 degrees , eight-loudspeaker array. Speech perception was assessed by using a four-alternative forced-choice spondee test, with speech presented from in front and adaptive background noise presented from 90 degrees to the left or right. Both tests were completed in the first implant alone and bilateral conditions. A questionnaire measured the pre- to postoperative change in the parent's ratings of the child's performance in specific listening situations. Items were related to speech perception, spatial hearing, or other qualities of hearing. Regular parental reports of device use, attitude and performance were collected. Most subjects were assessed at 6 mo after surgery, with two assessed at 13 mo. RESULTS: The 11 subjects demonstrated a great range of outcomes. For one subject, only anecdotal data were collected. Speech perception testing indicated that when noise was presented ipsilateral to the first implant, 8 of 10 subjects showed a benefit in the bilateral condition. None of the nine subjects tested showed a benefit when noise was contralateral to the first implant. Generally, there was no benefit to localization in the bilateral condition. For eight subjects, postoperative performance ratings were generally higher than preoperative ratings, particularly in the spatial hearing section. Anecdotal reports indicated that most subjects had a negative attitude toward, and gained limited experience with, the second implant alone. The subjects developed a range of speech perception skills, from detection to conversation level. Regarding the use of bilateral implants, attitudes were more positive and device use was consistent for eight subjects, and six parents reported some evidence of improved performance in daily life. CONCLUSIONS: Children over age 4 yr may gain significant additional benefit from a second implant, including improved speech perception in some noise contexts and functional advantages in daily life. There is, however, no evidence from this study to suggest that binaural listening skills, including localization, will develop during the first 6 mo. Furthermore, some children who may be committed users of a first implant may not adapt to or benefit from a second implant during the first 6 mo of device use. Although the factors influencing benefit cannot be clearly identified, limited preoperative auditory experience with the second ear, a delay of years between implants, relatively advanced age, and lack of second-implant-alone experience do not preclude benefit. Continued evaluation of these and additional subjects will clarify the factors that do contribute to benefit. Such information will be vital in helping families of implanted children to make an informed decision regarding a second implant.
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    12-month post-operative results for older children using sequential bilateral implants.
    Galvin, KL ; Mok, M ; Dowell, RC ; Briggs, RJ ( 2007-04)
    Within a long-term project investigating the perceptual benefits of bilateral implants, six children aged 5 to 15 yr received a second implant. Parent reports of functional performance were collected, and localization and spondee discrimination in noise was assessed. Outcomes varied from no benefit to significant benefit, although no improvement in localization was demonstrated. A major proportion of the benefit was likely due to headshadow effect. Success did not correlate with hearing aid use, age, time between implants, or second implant experience.
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    Spoken Language Development in Oral Preschool Children With Permanent Childhood Deafness
    Sarant, JZ ; Holt, CM ; Dowell, RC ; Rickards, FW ; Blamey, PJ (OXFORD UNIV PRESS, 2009)
    This article documented spoken language outcomes for preschool children with hearing loss and examined the relationships between language abilities and characteristics of children such as degree of hearing loss, cognitive abilities, age at entry to early intervention, and parent involvement in children's intervention programs. Participants were evaluated using a combination of the Child Development Inventory, the Peabody Picture Vocabulary Test, and the Preschool Clinical Evaluation of Language Fundamentals depending on their age at the time of assessment. Maternal education, cognitive ability, and family involvement were also measured. Over half of the children who participated in this study had poor language outcomes overall. No significant differences were found in language outcomes on any of the measures for children who were diagnosed early and those diagnosed later. Multiple regression analyses showed that family participation, degree of hearing loss, and cognitive ability significantly predicted language outcomes and together accounted for almost 60% of the variance in scores. This article highlights the importance of family participation in intervention programs to enable children to achieve optimal language outcomes. Further work may clarify the effects of early diagnosis on language outcomes for preschool children.