Audiology and Speech Pathology - Theses
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An investigation of the cognitive-linguistic profile of children with phonological delay and phonological disorder
All children make errors as they learn to talk, and while the vast majority of children spontaneously attain error-free speech within a predictable timeframe, approximately 6% to 10% of children struggle to achieve intelligible speech without intervention for no apparent anatomical, physiological, or psychological reason (American Psychiatric Association, 2013). While much is now known about the types of speech sound errors these young children make (McLeod & Baker, 2017), little is known about why they make these errors. One explanation for these errors is that some children fail to deduce the correct rules governing how speech sounds combine legally to form words. This PhD thesis investigates the cognitive–linguistic profile of two widely recognised subgroups of children with speech sound disorders (SSD) of unknown origin: phonological delay, that is, children who make typical speech errors but are delayed based on the norms for their chronological age, and phonological disorder, that is, children who make atypical speech errors that are heard in less than 10% of children at any age. Over a series of five empirical studies, three core executive function processes were investigated in the same cohort of monolingual English-speaking preschool children with phonological delay, phonological disorder, and typically developing speech. Children were tested on a series of standardised and commonly employed receptive vocabulary, phonological short-term memory and phonological working memory tasks, inhibitory control tasks, and rule abstraction and cognitive (set) shift tasks. Results indicated that children with phonological delay and phonological disorder had separate and distinct cognitive–linguistic profiles. Specifically, children with phonological disorder had phonological short-term memory skills (i.e., ability to mentally ‘hold’ verbal information briefly) similar to children with typical speech development, while children with phonological delay did not. Further, both SSD subgroups demonstrated significantly reduced phonological working memory performance (i.e., ability to mentally ‘hold’ and ‘manipulate’ verbal information) compared to children with typical speech development. However, for children with phonological delay, phonological working memory was capped by their ‘holding’ performance rather than a specific difficulty mentally ‘manipulating’ verbal information, while children with phonological disorder (who have intact ‘holding’ performance) had specific difficulties mentally ‘manipulating’ verbal information. Finally, children with phonological disorder also demonstrated significant domain-general rule abstraction and cognitive (set) shift deficits compared to their peers with typical speech development and phonological delay. All children had receptive vocabularies within the typical range. These findings have both clinical relevance and implications for theories of typical and impaired phonological development. Specifically, the findings highlight (1) the importance of differential diagnosis and recognising SSD subgroups in SSD research and clinical practice, (2) the importance of understanding the role of both domain-general cognitive processes and linguistic processes to phonological acquisition and explaining SSD subtypes, (3) how and why deficits in rule abstraction and cognitive (set) shift may contribute to atypical phonological development and atypical speech errors, and (4) the need for third-generation intervention approaches, that is, innovative and tailored treatment techniques that concurrently address speech and literacy difficulties by targeting underlying deficits.
Preventing hearing injury in the music industry
Sound levels in the live music industry have been demonstrated to reach levels capable of causing harm to the auditory system. The body of work presented here aimed to explore ways in which hearing injury can be prevented in the Australian music industry. To do so, multiple stakeholders were engaged, including venue owners, live-music sound engineers, audiologists and manufacturers of hearing protectors for musicians. Four discrete, mixed-methodology studies were conducted to address the topic. Study 1 aimed to investigate the clinical provision of musicians’ hearing protectors (MHPs) by audiologists and manufacturers of MHPs in Australia. Method. Audiologists and manufacturers were asked to complete one of two surveys, investigating the delivery of clinical care for musicians, and recommended processes relating to the manufacture of earplugs. Results. Inconsistencies in the clinical procedures were noted in both the practice of audiological care for musicians, and the recommendations made by manufacturers of MHPs. Study 2 aimed to investigate whether the use of, and satisfaction with, MHPs is influenced by the specific treatment delivered to musicians by audiologists. Method. Musicians rated their satisfaction with the services as delivered across the four treatment conditions. Results. No statistically significant differences across conditions were observed, however, certain aspects of care were perceived positively by musicians, such as the provision of a hearing test. Study 3 aimed to assess the hearing of live music sound engineers and their risk of hearing injury. Method. Participants completed a questionnaire on their hearing health as well as a hearing assessment. Results. Ninety-six percent of sound engineers reported having experienced at least one symptom of hearing injury during or after a work shift in music. Use of hearing protection was low, however, individuals who frequently wore hearing protection had significantly better hearing, particularly in the extended high frequencies. Study 4 aimed to investigate if the use of sound level management software can assist in reducing exposure levels in indoor live music venues. Method. Use of a commercial sound level management system in six indoor live-music venues of Melbourne was trialled. Results. Overall, there was no reduction in mean sound level (LAeq,T), however the number of nights on which extreme volume levels were recorded was reduced. Subjective questionnaires indicated that one-fifth of patrons would prefer lower sound levels than experienced. Overall, the results indicate there is a significant risk of hearing injury to individuals working within and attending live music venues in Australia. Findings indicated that there is a need for greater hearing awareness across all stakeholders. Audiologists would benefit from the development of best-practice guidelines for the care of musicians’ ears, while more broadly, the inclusion of EHF hearing thresholds would benefit in early detection and monitoring of noise-induced hearing loss. Greater research focus and hearing conservation training is needed for both LMSEs and staff in live-music venues, who would benefit from the implementation of strategies to manage venue sound levels in a way that takes into account the sound level preferences of patrons, while minimising the risk of hearing injury for all.
The emerging profession of speech therapy in Vietnam through pioneering eyes
Speech therapy is a new and rapidly growing profession in Vietnam, yet factors shaping its development are not well understood. Previous research in Majority World contexts suggests the emergence of rehabilitation professions may be shaped by a set of shared factors; however, the utility of this information to the Vietnamese context is not known. Further, little is known of the experience of practising a profession embedded with Eurocentric notions of health and disability in different cultural contexts. This doctoral research sought to extend understanding of these issues by exploring how the speech therapy profession is emerging in Vietnam through the experiences of a group of Vietnam’s first speech therapy graduates. This research reports a longitudinal, qualitative study employing participatory research methods conducted across the different cultural settings of Australia and Vietnam. Phase 1 of the research was conducted between 2013 and 2014. In 2013, interviews with 13 of the Vietnamese graduates one year following their graduation supported the development of a model conceptualising their work. In 2014, eight of the graduates were interviewed about their professional practice at two years post graduation. An advisory group of the graduates was also convened at this time to guide the research over its duration. This research phase confirmed the utility of the conceptual model characterising the graduates’ work and drew focus to the complexities that may arise when conducting participatory research in a cross-cultural setting. In Phase 2 of the research, creative research methods were introduced to explore the graduates’ work at three years post graduation. This research phase led to refinement and elaboration of the model conceptualising the graduates’ professional practice. In the final research phase, participants reflected upon their professional journeys in the four years since graduating and upon their participation in the research. This research identified that a diversity of factors is shaping the emergence of the speech therapy profession in Vietnam. Some factors are shared with other countries of the Majority World where the profession is practised; some are unique to Vietnam. Key themes conceptualising the graduates’ work—scope of practice, developing identity, confidence to practise, progressing the profession, and feelings—provide a rich, nuanced understanding of their experiences. This study revealed that the experience of pioneering a new profession in a Majority World context will be shaped by structural, personal, interpersonal, and cultural factors, and that initiatives to introduce the speech therapy profession into novel contexts will best be informed by local practitioners. Learnings from doing participatory research in a cross-cultural context relate to the integral role of the interpreter and engaging in research when the researcher and research participants are separated by language, time, and distance. The use of creative research methods supported the research participants’ experiences to be represented in diverse ways and addressed challenges posed by translation and the potential for misrepresentation of their experiences. This research highlighted that the experience of participating in research will be shaped by personal motivations and learnings that arise from research.
Going digital: enabling caregivers to optimise the linguistic environment for children with significant hearing loss
Early auditory exposure and linguistic interactions are fundamental in shaping the trajectory of typical language development in hearing children. These early linguistic experiences occur within the context of adult-child exchanges, through daily experiences, care routines and play. For children with prelingual hearing loss, early access to sound through hearing devices enables them to participate in these early linguistic experiences and can mitigate the potential negative effects resulting from hearing loss. In addition to early device fitting, research has demonstrated a strong association between the manner, content and amount of spoken language which infants and toddlers are exposed to at home, to enhance their learning, and their later language outcomes. While there is growing research awareness with regard to measuring the amount of talk directed to children, establishing how best to provide feedback to caregivers on their language contributions to their children in the context of everyday life, has been a challenge in traditional service delivery models. To this end, automated speech and language processing technology, also known as the Language ENvironment Analysis (LENA) system, offers clinicians the possibility of measuring and imparting quantified information to parents about their child’s auditory-language environment. Additionally, the use of mobile applications has been gaining traction as an accessible method of promoting health. The Daily Vroom App (DVA) for example, was created as an outreach initiative to communicate developmental research evidence to parents, presented as practical and implementable content. The DVA content takes the form of daily tips aimed at turning everyday moments for parents and their young children into opportunities for shared interaction. This study evaluated these two technology-driven interventions, using LENA technology and the Daily Vroom App, as ways to increase the amount of conversational turns and words spoken by adults to children. The present study firstly investigated relationships between family, maternal and child characteristics and language counts (measured using the LENA system) recorded in the children’s natural home environments. Secondly, changes in the participants’ adult word count and adult-child conversational turn count from baseline were examined after mothers received feedback based on LENA generated language estimates and/or, after mothers had used the Daily Vroom App. Thirdly, survey findings regarding the use of LENA technology and the DVA from the perspective of clinicians and mothers were explored. There were 10 mother-child dyads (six hearing children and four children with bilateral severe-to-profound hearing loss) who participated in a prospective intervention trial. After establishing each dyad’s baseline LENA-generated language counts (adult words and adult-child conversational turns), mean percentage changes in their language counts were analysed for three study conditions: LENA-Only recordings of adult-child verbal interactions in the child’s natural environments (Condition LO); adult-child verbal interactions following specific, individualised feedback from a clinician regarding the quantity of talk (LENA Feedback- Condition LF); and DVA use which provided tips for shared parent-child interactions in addition to Condition LF (LENA Feedback and App- Condition LFA). Maternal and child measures were administered at the beginning of the study. Demographic information and responses to a survey on the use of LENA and mobile technology were collected from participating clinicians and mothers. Key group findings suggested that the mean percentage increases in adult word and conversational turn counts from baseline were significant after the interventions (i.e. providing participants with LENA feedback and mother’s use of the mobile app), compared to Condition LO where only LENA recordings were completed. Significant correlations were found between mothers’ occupational skill level, maternal receptive vocabulary and their ratings of eHealth literacy. Participants assigned the DVA an overall mean quality rating of 3.85 out of 5. Significant positive relationships were found between objective app quality indicators (engagement, aesthetics, information) and participants’ perceived impact (on help-seeking, intention to change and behaviour change) of using the DVA. These two contemporary technologies (LENA and DVA) were demonstrated to support adult language input and conversational turns in the home environments for mothers of children with normal hearing, and children with bilateral significant hearing loss. This study addressed the question of whether providing structured information and feedback to mothers would be associated with a change in maternal language behaviours. This study also contributed to current knowledge regarding the practical applications of the LENA system and the Daily Vroom App as a complement to current service models, extending intervention practices beyond the therapy room.
Vestibular migraine: a challenging illness to live with and to manage: a qualitative study of patients’ and specialists’ perspectives
Vestibular migraine (VM) is one of the most common causes of recurrent vertigo with significant effects on patients’ health-related quality of life measures and psychological well-being. It is widely accepted that VM is associated with a range of diagnostic and management challenges for practitioners, predominantly due to the lack of a gold standard diagnostic test and absence of a preferred drug of choice. Consequently, the existing literature is mostly focused on optimising the diagnostics and treatment protocols. Yet, little is known about the therapeutic needs of those who suffer from VM and health professionals’ strategies in providing care beyond medication. This doctoral thesis addresses these gaps in knowledge in two ways: first, by exploring the experiences of vestibular migraineurs in their daily lives and in the management of their condition; second, by juxtaposing these experiences with an exploration of vestibular specialists’ (VSs) perspectives on the management and care of people with VM. This thesis entailed three phases. In Phase A, a preliminary observation of several vestibular migraineurs’ appointments with VSs was conducted to inform the overall direction of the thesis and to fine-tune the research questions. Phase B adopted a qualitative descriptive method across two consecutive studies. In Study 1, 11 adults with VM were interviewed. This study was informed by the preliminary observation in Phase A and explored two aims: 1a) vestibular migraineurs’ lived experiences and therapeutic needs, 1b) vestibular migraineurs’ experiences with healthcare professionals (HCPs). The findings are visually presented in two models: The first model describes participants’ perceptions of living with VM. In this model, VM is depicted as a ‘wall’ to represent participants’ perception of living with extensive functional and psychosocial restrictions. The individual is presented at the centre, surrounded by six aspects of life (i.e., lifestyle, occupation, personal life, self-sufficiency, social network and self-image) and encircled by VM. Hopelessness and isolation are presented adjacent to the VM ‘wall’ to highlight the psychological effects of a restricted life. The second model is a map of vestibular migraineurs’ journeys from symptom presentation to diagnosis/symptom control. This map illustrates the experiences of vestibular migraineurs with different HCPs and represents the convoluted, long and often frustrating journey that patients embark on to find a diagnosis and, possibly, some level of symptom control. This model shows that vestibular migraineurs’ journeys often entail multiple misdiagnoses, dismissals and irrelevant referrals, particularly when patients seek medical advice from general practitioners (GPs). This experience often leads to frustration and loss of trust towards primary care physicians. By contrast, participants depicted a more positive, trusting experience when seeing VSs. Compared to GPs, patients often perceived VSs as more knowledgeable and competent in managing their illness, largely because VSs acknowledged the severity of their illness and did not dismiss them. Vestibular migraineurs’ satisfaction with VSs provided a rationale for exploring these practitioners’ perspectives. The purpose was to elucidate the source of patients’ higher levels of satisfaction and to explore the clinical strategies that VSs adopted in managing VM. Study 2 explored the perspectives of 10 VSs on two topics: 2a) the complexities of VM management and 2b) the features of optimum VM care. VSs were recruited from several fields of balance disorder management including neuro-otology, vestibular audiology, vestibular physiotherapy, and ear, nose and throat surgeons. The outcomes are depicted in two models. The first model illustrates the multidimensionality of complexities posed by VM, indicating that VM is a complex illness to manage due to three factors: 1) scientific ambiguities, 2) patient-related challenges and 3) professional challenges. The second model proposes a framework for VM quality management: ‘SAIPHE’. SAIPHE stands for the six elements that were considered essential for VM quality care: self-efficacy, access, individualisation, wholistic, and education. Each of these elements are described in detail in the thesis. Study 2 concludes Phase B of this thesis. In Phase C, the data obtained in this body of work was triangulated. The outcomes of Study 1 and Study 2 were juxtaposed to examine their consistency. Patients’ accounts of the challenges of living with VM were compared with VSs’ perspectives and elements of SAIPHE were juxtaposed with Study 1 (vestibular migraineurs’ lived experience and expectations of their practitioners). Finally, VSs’ perspectives on features of VM patients’ education/consultation were integrated with vestibular migraineurs’ articulated educational needs and were developed into a VM-specific consultation framework. Overall, the outcomes of this thesis indicate that VM is a complex illness to live with and to manage as its effects extend beyond its immediate symptoms. Patients suffer from functional and psychological implications that, if unattended, could have catastrophic sequelae. Despite advances in evidence-based knowledge, and despite the consistency of VSs’ perspectives, vestibular migraineurs’ needs and expectations are not reflected in non-specialised clinical care, particularly general practice, and frequent misdiagnosis and dismissals create a barrier to timely management of patients’ illnesses. This thesis supports the clinical recommendation of promoting a care plan that extends beyond symptom management and incorporates patient education and management of functional and psychological effects of VM.
Outcomes for adult cochlear implant recipients with functional pre-operative hearing
BACKGROUND & AIMS: In recent years, the population of persons with hearing loss attending cochlear implant (CI) centres for candidacy discussions has shifted to include those with greater hearing than in the past. Specifically, persons may have residual low frequency hearing ranging from normal to moderately severe with profound loss in the high frequencies (i.e. partial deafness (PD)). To support CI clinicians’ provision of evidence-based recommendations to adults with PD, new clinical outcome data, candidacy guidelines, and predictive factors associated with preservation of acoustic hearing are required to address the following: assessment of speech perception benefits for adults with PD using CIs, quantifying risk for loss of residual hearing, and evaluating outcome by electrode array type. METHOD: This ambidirectional study design used a prospective cohort of adults with PD and two retrospective analyses of adults who received a CI at the Royal Victorian Eye and Ear Hospital (RVEEH). To assess speech perception benefits for adults with PD as compared with traditional CI recipients (defined as severe-to-profound or poorer audiometric thresholds pre-implant), a group of 27 adults with PD were compared to a matched group of traditional CI recipients with all data sourced from the RVEEH database. All recipients were using perimodiolar arrays. To assess hearing preservation outcomes, 154 adults with PD were studied prospectively. These adults were identified as proceeding with the device of interest, a CI with a thin straight electrode array (TSEA). To assess speech perception outcomes by electrode array type, a group of 70 adults with PD using perimodiolar CIs sorted from the database were compared with a group of 63 adults with PD using TSEAs. RESULTS: There were no significant differences in speech perception outcomes for adults with PD compared with those with profound hearing loss who received perimodiolar arrays. Median change in low frequency hearing for adults with PD using a TSEA was -22.5 dB HL. Hearing preservation was assessed further for a subset of 78 defined as having ‘functional’ low frequency hearing pre-implant (≤70 dB HL). For persons who had a pre-implant low frequency pure tone median of ≤45 dB HL, functional hearing was preserved in 75% of cases. No significant differences were found for speech perception outcomes based on electrode array type for the two groups of adults with PD. For persons using a TSEA, it was found that those who had preserved hearing and used electro-acoustic stimulation (EAS) performed significantly better than their peers with electric-only hearing. CONCLUSION: The present study demonstrated that clinicians may use existing CI candidacy guidelines to counsel adults with PD who are considering a CI. The presence of low frequency hearing ≤45 dB HL pre-implant was associated with preservation of functional acoustic hearing in 75% of cases post-implant. Electrode array type was not found to be significantly associated with speech perception outcomes for adults with PD, however those that preserved hearing and used EAS demonstrated superior outcomes. These data provide evidence-based guidelines for counselling adults with PD pre-implant with respect to their potential to benefit and the associated risks to hearing.
Development and validation of the short language measure (SLaM): a brief measure of general language ability for children in their first year at school
The identification of children with language difficulties relies on the referral of children to speech-language services. Yet, the referrers of young school-aged children cannot always accurately discriminate those with and without language difficulties. Consequently, a high proportion of children with language difficulties are never referred for services and many children referred for suspected language difficulties have age-appropriate communication skills. The administration of a short language measure by speech-language therapists or paraprofessionals to identify children who require further language evaluation could improve the accuracy of language service referrals. However, existing short language measures for young school-aged children lack sufficient discrimination capacity. This may be due to the inadequate development of available measures, which have omitted crucial test development steps. The aim of this project was to create a sufficiently accurate, valid and reliable short language measure for children in their first year at school by applying stringent test development procedures.
Patient-centred communication in audiology education: an exploration of perspectives and practice
Patient-centred communication is recognised as the cornerstone to quality healthcare delivery and is associated with positive patient health outcomes. It is a core component of established healthcare disciplines, such as medicine and physiotherapy and is beginning to gain recognition and curriculum space in younger disciplines such as audiology. While there has been a growth in patient communication education in the audiology curricula, studies have reported that students feel ill-prepared when communicating with patients about their hearing impairment. Research remains sparse in exploring the current gaps in communication skills education in audiology. In addition, little is known about student-patient communication in a naturalistic setting such as clinical placements. Therefore, the overarching aim of the research was to explore patient-centred communication in audiology education in an Australian context. This research contains three studies. The first study aimed to examine the perspectives of audiology educators towards patient-centred communication. Semi-structured interviews were conducted with nine audiology program coordinators and key teaching staff to examine the barriers and facilitators to teaching patient-centred communication. Content analysis of the transcribed interviews revealed four emerging themes: professional culture and values, contextual factors, knowledge and understanding of patient-centred communication and individual factors. The findings shed light onto the competing tension between the teaching staff’s value towards patient-centred communication and the biomedically-driven professional culture that places a priority towards technical skills. The aim of the second study was to explore audiology students’ perception of their own clinical communication and learning in the audiology program. In a semi-structured interview using video reflexivity, fifteen students were asked to co-view their own filmed clinical appointment and discuss areas that were most salient to them. Thematic analysis revealed the themes of striving to be patient-centred, assessment shapes behaviour, and power relations to have the biggest influence on students’ own clinical communication. The final theme of what students want uncovered students’ perception towards different teaching methods. These findings showed students’ motivation to demonstrate patient-centred communication can be hindered by conflicting educational standards. The final study examined two interrelated research questions: i) how do audiology students co-construct the communicative tasks in a supervised hearing assessment appointment?; and ii) how does students’ communication align with the principles of patient-centred communication? Final year audiology students from two Australian universities were video-recorded during one of their university-based clinical placements. Two analytical procedures were performed using genre analysis and the development of The Patient-Centred Analytical Framework for Audiology to map students’ patient-centred communication. Findings showed clear communication patterns in how students structured the appointment in the presence of the clinical educator. Students also demonstrated patient-centred communication skills in fostering the relationship and gathering patient information. However, shared decision-making, enablement and responding to patients’ emotional concerns were rarely observed. A significant relationship was found between the clinical educators’ interjection and students’ patient-centred communication patterns. Collectively, these findings identified strengths and gaps in students’ patient-centred communication, and raised questions about the clinical educator’s role in the provision of learning opportunities during the clinical placement. This body of work demonstrated the complexities in teaching and learning patient-centred communication and highlighted the tension between existing barriers and enablers to the implementation of clinical communication education. Irrespective of external barriers, teaching and learning relies on educators’ knowledge and understanding of patient-centred communication. This may include training educators and providing clear guidelines to strengthen the alignment between educational content required for practice, as well as skills to optimise student feedback. To change the technical and biomedical focus within the audiological culture, the development of a unified teaching framework for communication could inform teaching content and assessment rubrics. Ultimately, communication is a skill that requires the opportunity for development. This can be facilitated by integrating communication education longitudinally into the audiology curriculum. Continual reinforcement of communication skills over the course of the program will sustain students’ communication learning and promote skilled communicators.
Speech and language phenotyping in children with cleft lip and/or palate and their unaffected relatives
Background: Cleft lip and/or palate (CL/P) is one of the most common birth defects. Non-syndromic CL/Ps make up 70% of cases and are associated with complex phenotypes, challenging accurate clinical diagnosis and prognostication. Children with CL/P may have impaired language, or disordered speech associated with velopharyngeal insufficiency (VPI). Existing research defines several sub-clinical cleft phenotypes, identified from unaffected relatives, that may advance clinical knowledge and contribute to our understanding of genetic aetiology. VPI has long been suggested as a sub-clinical phenotype, but only recently studied. Aims: Broad aims were: (1) to systematically review the literature exploring speech and language skills of children with submucous cleft palate (SMCP); (2) to describe the speech and language characteristics of probands with different cleft types; and (3) to provide sub-clinical speech phenotyping for clinically ‘unaffected’ relatives of probands with cleft lip with or without palate (CL±P). Methods: (1) Five databases were comprehensively searched. Included studies reported speech or language profiles of individuals with SMCP. (2) Participants with clefts (overt CL/P n = 37; SMCP n = 15) were recruited from the cleft registry at the Royal Children’s Hospital (RCH), Melbourne, Australia. Language data from non-cleft participants was obtained from the Early Language in Victoria Study (n = 129). (3) Probands with overt clefts were identified from the RCH cleft registry, and their unaffected family members were contacted for participation (n = 189). Non-cleft participants were recruited from Melbourne, Australia (n = 207). All participants had non-syndromic diagnoses with no medical conditions likely to impact communication. Non-cleft participants also had no known family history of clefting. Speech was assessed perceptually, using common clinical tools, and instrumentally with the Nasometer. Language was assessed using the Clinical Evaluation of Language Fundamentals, Fourth Edition and the Children’s Communication Checklist, Second Edition. Non-verbal IQ was screened using the Weschler Abbreviated Scale of Intelligence, Second Edition. Results: (1) Children with SMCP may present with speech difficulties similar to those experienced by individuals with overt clefts. There is a dearth of literature exploring the language abilities of this population. (2) Children with overt clefts had language skills that were comparable to their non-cleft peers. Those with SMCP had variable speech and language performance, with overall poorer language than those with or without overt clefts. Participants with SMCP and poor language also had low non-verbal IQ. (3) Speech in unaffected relatives was not significantly different to that of a matched non-cleft cohort. Discussion & conclusion: Detailed phenotyping from this thesis highlights a diversity in communication profiles between and within groups of individuals with different cleft types. Results emphasise the importance of individualised assessment, where clinicians do not make assumptions based on a child’s cleft. Conclusions from the SMCP study suggest that other unidentified neurodevelopmental disorders may be present, questioning the accuracy of truly ‘non-syndromic’ diagnoses. Data from the third aim suggest that VPI is not a significant sub-clinical phenotype of non-syndromic CL±P and thus may not warrant further exploration in familial genetic investigations. Outcomes contribute to the complex CL/P phenotyping and genotyping landscape.
Early feeding and communication skills in children born at <30 weeks of gestational age
Introduction Children born preterm are at risk of adverse neurodevelopment, potentially including disordered feeding, voice, speech, and language. The literature lacks an integrated picture of these domains, and predictors are uncertain, though preliminary evidence suggests that oromotor feeding may predict voice, speech, and language. This study had the following aims, addressed at various times across three waves of data collection at 12, 24, and 36 months of age: 1. To characterise the feeding abilities of children born at <30 weeks of gestational age in comparison with children born at term 2. To determine significant predictors of feeding ability in children born at <30 weeks of gestational age 3. To characterise the voice, speech, and language abilities of children born at <30 weeks of gestational age in comparison with children born at term 4. To determine significant predictors of voice, speech, and language ability in children born at <30 weeks of gestational age; and a. In particular to evaluate early feeding abilities as a predictor of later voice, speech, and language abilities Methods Within two weeks of birth, 149 children born <30 weeks’ gestational age, and 151 term-born children were recruited from the Royal Women’s Hospital. At 12 months’, the Schedule for Oromotor Assessment (SOMA) was administered. At 24 months’, the Communication and Symbolic Behavior Scales–Infant Toddler Profile, and Bayley Scales of Infant-Todder Development–3rd Edition were administered. At 36 months’, the Behavioral Pediatrics Feeding Assessment Scale, the Pediatric Voice Handicap Index, the Grade, Roughness, Breathiness, Asthenia, Strain Scale, the Diagnostic Evaluation of Articulation and Phonology and the Preschool Language Scales—5th Edition were administered. Outcomes were compared between groups, and potential predictors were analysed. Results Children born <30 weeks’ performed worse than term-born peers at oromotor feeding at 12 months’, language at 24 months’, and language at 36 months’. Voice, speech, and feeding behaviour at 36 months’ were similar between groups. Oromotor feeding at 12 months’ was predicted (p<0.05) by infant neurobehaviour, brain biparietal diameter on Magnetic Resonance Imaging (MRI), and neonatal surgery; but not by other MRI metrics (e.g. white matter score), sex, gestational age at birth (GA), birth-weight, social risk, tube feeding, or respiratory support. Language at 24 months’ was predicted (p<0.05) by sex, GA, hearing loss, and multilingualism; but not birth-weight, maternal education, neonatal brain abnormality, medical risk, or early feeding. Language at 36 months’ was predicted (p<0.05) by sex, neurodevelopmental disorder, and high social risk; but not GA, birth-weight, chronic lung disease, multilingualism, or early feeding. Voice at 36 months’ was predicted (p<0.05) only by chronic lung disease; speech at 36 months’ was not predicted by any hypothesised risk factors. Conclusion Oromotor feeding at 12 months’, and language across the early years were concerns for children born at <30 weeks’ GA. Speech and voice were not affected, contrary to previous reports. Predictors reported in this study may be used to identify those children at greatest risk of adverse outcomes, facilitating surveillance and timely intervention.
Mild and moderate congenital hearing loss in childhood: trends and associations with language outcomes
Background: Children born with mild and moderate bilateral hearing loss experience poorer language outcomes than peers without hearing loss. Following implementation of universal newborn hearing screening (UNHS) in the early 2000s, most children are now fitted with hearing aids very early, even without firm evidence of efficacy. Filling this knowledge gap would support clinicians and families to make appropriate decisions for affected children. Aims: In population-based samples of children born with mild and moderate bilateral hearing loss in two age groups, I aimed to describe the: 1) language and child wellbeing outcomes at 5-8 years of age examined both by system of hearing loss detection and age at detection; 2) relationship between measures of hearing ability (aided and unaided) and speech/language outcomes at 5-7 years of age; and 3) expressive vocabulary of children at age 1-3 years, with comparison to same-aged children without hearing loss. Methods: All participants were drawn from population-based studies or databanks with comparable measures and demographic composition in Victoria and New South Wales. In Aim 1, 21 directly assessed children (5-7 years) were analysed with 125 children (5-8 years) from historical hearing loss cohorts and 1217 children (7 years) without known hearing loss. For Aim 2, hearing aid data were obtained for 19 directly assessed children. In Aim 3, questionnaire data were compared between 20 children (1-3 years) with and 1711 children (2 years) without known hearing loss. Language was assessed or parent-reported, with additional data collected by parent questionnaire. Aim 1 was analysed using unadjusted and adjusted regression models, with potential confounders identified a priori. For Aims 2 and 3, analyses were descriptive and exploratory. Results: Outcomes for 5-7 year olds with moderate loss improved across detection systems spanning opportunistic through to UNHS (mean expressive language p for trend .05, receptive vocabulary p for trend .06) and were better when diagnosed before age 6 months. Children with mild loss did not show similar benefit, despite trends toward earlier diagnosis and hearing aid fitting. Children with mild-moderate loss had poorer expressive language than children without loss (adjusted mean difference -8.9 points, 95% CI -14.7 to -3.1). Audibility measures correlated with unaided hearing (r=-.60 to -.79, p=.02 to <.001) and speech recognition ability (r=-.63 to -.73, p=.04 to .01). Unaided and aided hearing measures did not show associations with speech and language. On average 1-3 year olds with, versus without, hearing loss had lower expressive vocabulary raw scores even though older at assessment. Language of children with mild loss was on average 9 months behind expectations (SD 5.6 months), moderate loss on average 6.6 months behind (SD 6.7 months). Conclusions: Children with mild and moderate hearing loss show early language delays that persist into primary school. Children with moderate loss showed some benefit from earlier detection and fitting with hearing aids. Children with mild loss did not, which is concerning given the current practice of earlier hearing aid fitting. A population-based trial of hearing aids for mild losses would clarify the benefits versus costs of this approach.
The effect of early otitis media on long-term binaural processing
INTRODUCTION: One of the most common childhood ear pathologies is otitis media with effusion. The immediate impacts of otitis media are well known, and include fluctuating conductive hearing loss and impaired speech intelligibility. A more subtle influence, present years after the otitis media clears, includes disruptions to binaural cue processing, specifically, the cues that arise when there are differences in the signal arriving at each ear. It is the processing of these difference cues that allows a listener to follow speech in noisy environments and, if compromised in school-age children, may have negative ramifications on classroom listening and academic performance. There is a recognised link between otitis media in early childhood and impaired processing of binaural cues in subsequent years (i.e. longer-term). However, the mechanisms influencing this reported association are yet to be fully explored. OBJECTIVES: This thesis examined the implications of early conductive hearing loss (associated with otitis media) on longer-term binaural processing, at a behaviourally measurable level, and at the level of an auditory evoked potential. DESIGN: Binaural listening ability was determined using standard clinical assessment measures in school-age children with clinical histories documenting hearing and middle-ear status throughout early childhood. Additionally, an evoked potential measure was used as an objective measure of binaural processing ability, with comparisons made between the electrophysiological measure and a behavioural correlate pre- and post-auditory training. RESULTS: The two most important contributions made by this doctoral project were 1) the established relationship between an otitis media related conductive hearing loss history in the first four years of life and reduced spatial processing ability at school-age, and 2) the findings that suggest spatial processing is not completely dependent upon the activity at the subcortical centres. IMPLICATIONS: This work increases understanding of the mechanisms underlying binaural processing and its development. Findings also have significant clinical implications, demonstrating a need for earlier identification and/or treatment of young children presenting with conductive hearing loss associated with otitis media.