Audiology and Speech Pathology - Research Publications
Now showing items 1-12 of 249
The neural basis of nonword repetition in children with developmental speech or language disorder: An fMRI study
(PERGAMON-ELSEVIER SCIENCE LTD, 2020-02-17)
Developmental language disorder (DLD) and developmental speech disorder (DSD) are highly prevalent childhood conditions. An impaired ability to repeat nonsense words ("nonword repetition"), is claimed to be a robust behavioural marker for these conditions. Yet how brain function is altered during this task remains poorly understood. Previous research suggests that DLD or DSD may be associated with reduced brain activation in the inferior frontal and posterior temporal regions when compared to controls. However, this research is limited by within and between group variability in age, speech/language phenotype, and comorbidities. Here, we used functional MRI to examine brain activation during nonword repetition. As anticipated, behavioural findings confirmed that the DLD and DSD groups had poorer nonword repetition performance compared to typical controls. In contrast, fMRI revealed no statistically significant differences in brain activation, despite the groups appearing to engage slightly different regions when compared at identical thresholds. Therefore, whilst nonword repetition is a sensitive clinical marker for DLD and DSD, the findings from this study suggest that this task is not a sensitive brain MRI marker for children with these disorders, unlike for individuals with single gene mutations like FOXP2 mutations.
Speech discrimination performance in multiple sclerosis dataset
The most complex interactions between human beings occur through speech, and often in the presence of background noise. Understanding speech in noisy environments requires the integrity of highly integrated and widespread auditory networks likely to be impacted by multiple sclerosis (MS) related neurogenic injury. Despite the impact auditory communication has on a person's ability to navigate the world, build relationships, and maintain employability; studies of speech-in-noise (SiN) perception in people with MS (pwMS) have been minimal to date. Thus, this paper presents a dataset related to the acquisition of pure-tone thresholds, SiN performance and questionnaire responses in age-matched controls and pwMS. Bilateral pure-tone hearing thresholds were obtained at frequencies of 250 hertz (Hz), 500 Hz, 750 Hz, 1000 Hz, 1500 Hz, 2000 Hz, 4000 Hz, 6000 Hz and 8000 Hz, and hearing thresholds were defined as the lowest level at which the tone was perceived 50% of the time. Thresholds at 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz were used to calculate the four-tone average for each participant, and only those with a bilateral four tone average of ≤ 25 dB HL were included in the analysis. To investigate SiN performance in pwMS, pre-recorded Bamford-Kowal-Bench (BKB) sentences were presented binaurally through headphones at five signal-to-noise ratios (SNR) in two noise conditions: speech-weighted noise and multi-talker babble. Participants were required to verbally repeat each sentence they had just heard; or indicate their inability to do so. A 33-item questionnaire, based on validated inventories for specific adult clinical populations with abnormal auditory processing, was used to evaluate auditory processing in daily life for pwMS. For analysis, pwMS were grouped according to their Expanded Disability Status Scale (EDSS) score as rated by a neurologist. PwMS with EDSS scores ≤ 1.5 were classified as 'mild' (n = 20); between 2 and 4.5 as 'moderate' (n = 16) and between 5 and 7 as 'advanced' (n = 10) and were compared to neurologically healthy controls (n = 38). The outcomes of the SiN task conducted in pwMS can be found in Iva et al., (2021). The present data has important implications for the timing and delivery of preparatory education to patients, family, and caregivers about communication abilities in pwMS. This dataset will also be valuable for the reuse/reanalysis required for future investigations into the clinical utility of SiN tasks to monitor disease progression.
White matter microstructure is associated with language in children born very preterm
(ELSEVIER SCI LTD, 2018-01-01)
Very preterm birth is associated with altered white matter microstructure and language difficulties, which may compromise communication, social function and academic achievement, but the relationship between these two factors is unclear. The aim of this study was to explore associations between white matter microstructure and language domains of semantics, grammar and phonological awareness at 7-years of age on a whole-brain level and within the arcuate fasciculus, an important language pathway, in very preterm and term-born children. Language was assessed in 145 very preterm-born (<30 weeks' gestation and/or <1250 g birth weight) and 33 term-born children aged 7 years. Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), mean diffusivity (MD), axon orientation dispersion and axon density were estimated from diffusion magnetic resonance images also obtained at 7 years. The correlation between diffusion values and language was assessed using Tract-Based Spatial Statistics (TBSS). The arcuate fasciculus was delineated using constrained spherical deconvolution tractography and diffusion parameters from this tract were related to language measures using linear regression. While there was evidence for widespread associations between white matter microstructure and language, there was little evidence of differences in these associations between very preterm and term-born groups. TBSS analyses revealed that higher FA and lower AD, RD, and MD in major fibre tracts, including those subserving language, were associated with better semantic, grammar and phonological awareness performance. Higher axon density in widespread fibre tracts was also associated with better semantic performance. The tractography analyses of the arcuate fasciculus showed some evidence for associations between white matter microstructure and language outcomes. White matter microstructural organisation in widespread fibre tracts, including language-relevant pathways, was associated with language performance in whole-brain and tract-based analyses. The associations were similar for very preterm and term-born groups, despite very preterm children performing more poorly across language domains.
The need for improved detection and management of adult-onset hearing loss in australia.
(Hindawi Limited, 2013)
Adult-onset hearing loss is insidious and typically diagnosed and managed several years after onset. Often, this is after the loss having led to multiple negative consequences including effects on employment, depressive symptoms, and increased risk of mortality. In contrast, the use of hearing aids is associated with reduced depression, longer life expectancy, and retention in the workplace. Despite this, several studies indicate high levels of unmet need for hearing health services in older adults and poor use of prescribed hearing aids, often leading to their abandonment. In Australia, the largest component of financial cost of hearing loss (excluding the loss of well-being) is due to lost workplace productivity. Nonetheless, the Australian public health system does not have an effective and sustainable hearing screening strategy to tackle the problem of poor detection of adult-onset hearing loss. Given the increasing prevalence and disease burden of hearing impairment in adults, two key areas are not adequately met in the Australian healthcare system: (1) early identification of persons with chronic hearing impairment; (2) appropriate and targeted referral of these patients to hearing health service providers. This paper reviews the current literature, including population-based data from the Blue Mountains Hearing Study, and suggests different models for early detection of adult-onset hearing loss.
Validity of the AusTOM scales: a comparison of the AusTOMs and EuroQol-5D.
(Springer Science and Business Media LLC, 2004-11-13)
BACKGROUND: Clinicians require brief outcome measures in their busy daily practice to document global client outcomes. Based on the UK Therapy Outcome Measure, the Australian Therapy Outcome Measures were designed to capture global therapy outcomes of occupational therapy, physiotherapy and speech pathology in the Australian clinical context. The aim of this study was to investigate the construct (convergent) validity of the Australian Therapy Outcome Measures (AusTOMs) by comparing it with the EuroQuol-5D (EQ-5D). METHODS: The research was a prospective, longitudinal cohort study, with data collected over a seven month time period. The study was conducted at a total of 13 metropolitan and rural health-care sites including acute, sub-acute and community facilities. Two-hundred and five clients were asked to score themselves on the EQ-5D, and the same clients were scored by approximately 115 therapists (physiotherapists, speech pathologists and occupational therapists) using the AusTOMs at admission and discharge. Clients were consecutive admissions who agreed to participate in the study. Clients of all diagnoses, aged 18 years and over (a criteria of the EQ-5D), and able to give informed consent were scored on the measures. Spearman rank order correlation coefficients were used to analyze the relationships between scores from the two tools. The clients were scored on the AusTOMs and EQ-5D. RESULTS: There were many health care areas where correlations were expected and found between scores on the AusTOMs and the EQ-5D. CONCLUSION: In the quest to measure the effectiveness of therapy services, managers, health care founders and clinicians are urgently seeking to undertake the first step by identifying tools that can measure therapy outcome. AusTOMs is one tool that can measure global client outcomes following therapy. In this study, it was found that on the whole, the AusTOMs and the EQ-5D measure similar constructs. Hence, although the validity of a tool is never 'proven', this study offers preliminary support for the construct validity of AusTOMs.
Recessive variants in ZNF142 cause a complex neurodevelopmental disorder with intellectual disability, speech impairment, seizures, and dystonia
(NATURE PUBLISHING GROUP, 2019-11-01)
PURPOSE: The purpose of this study was to expand the genetic architecture of neurodevelopmental disorders, and to characterize the clinical features of a novel cohort of affected individuals with variants in ZNF142, a C2H2 domain-containing transcription factor. METHODS: Four independent research centers used exome sequencing to elucidate the genetic basis of neurodevelopmental phenotypes in four unrelated families. Following bioinformatic filtering, query of control data sets, and secondary variant confirmation, we aggregated findings using an online data sharing platform. We performed in-depth clinical phenotyping in all affected individuals. RESULTS: We identified seven affected females in four pedigrees with likely pathogenic variants in ZNF142 that segregate with recessive disease. Affected cases in three families harbor either nonsense or frameshifting likely pathogenic variants predicted to undergo nonsense mediated decay. One additional trio bears ultrarare missense variants in conserved regions of ZNF142 that are predicted to be damaging to protein function. We performed clinical comparisons across our cohort and noted consistent presence of intellectual disability and speech impairment, with variable manifestation of seizures, tremor, and dystonia. CONCLUSION: Our aggregate data support a role for ZNF142 in nervous system development and add to the emergent list of zinc finger proteins that contribute to neurocognitive disorders.
neuroBi: A Highly Configurable Neurostimulator for a Retinal Prosthesis and Other Applications
(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2015-01-01)
To evaluate the efficacy of a suprachoroidal retinal prosthesis, a highly configurable external neurostimulator is required. In order to meet functional and safety specifications, it was necessary to develop a custom device. A system is presented which can deliver charge-balanced, constant-current biphasic pulses, with widely adjustable parameters, to arbitrary configurations of output electrodes. This system is shown to be effective in eliciting visual percepts in a patient with approximately 20 years of light perception vision only due to retinitis pigmentosa, using an electrode array implanted in the suprachoroidal space of the eye. The flexibility of the system also makes it suitable for use in a number of other emerging clinical neurostimulation applications, including epileptic seizure suppression and closed-loop deep brain stimulation. Clinical trial registration number NCT01603576 (www.clinicaltrials.gov).
Directing human induced pluripotent stem cells into a neurosensory lineage for auditory neuron replacement.
(Mary Ann Liebert Inc, 2014-08-01)
Emerging therapies for sensorineural hearing loss include replacing damaged auditory neurons (ANs) using stem cells. Ultimately, it is important that these replacement cells can be patient-matched to avoid immunorejection. As human induced pluripotent stem cells (hiPSCs) can be obtained directly from the patient, they offer an opportunity to generate patient-matched neurons for transplantation. Here, we used an established neural induction protocol to differentiate two hiPSC lines (iPS1 and iPS2) and one human embryonic stem cell line (hESC; H9) toward a neurosensory lineage in vitro. Immunocytochemistry and qRT-PCR were used to analyze the expression of key markers involved in AN development at defined time points of differentiation. The hiPSC- and hESC-derived neurosensory progenitors expressed the dorsal hindbrain marker (PAX7), otic placodal marker (PAX2), proneurosensory marker (SOX2), ganglion neuronal markers (NEUROD1, BRN3A, ISLET1, ßIII-tubulin, Neurofilament kDa 160), and sensory AN markers (GATA3 and VGLUT1) over the time course examined. The hiPSC- and hESC-derived neurosensory progenitors had the highest expression levels of the sensory neural markers at 35 days in vitro. Furthermore, the neurons generated from this assay were found to be electrically active. While all cell lines analyzed produced functional neurosensory-like progenitors, variabilities in the levels of marker expression were observed between hiPSC lines and within samples of the same cell line, when compared with the hESC controls. Overall, these findings indicate that this neural assay was capable of differentiating hiPSCs toward a neurosensory lineage but emphasize the need for improving the consistency in the differentiation of hiPSCs into the required lineages.
Neural Correlates of Developmental Speech and Language Disorders: Evidence from Neuroimaging.
(Springer Science and Business Media LLC, 2014)
Disorders of speech and language arise out of a complex interaction of genetic, environmental, and neural factors. Little is understood about the neural bases of these disorders. Here we systematically reviewed neuroimaging findings in Speech disorders (SD) and Language disorders (LD) over the last five years (2008-2013; 10 articles). In participants with SD, structural and functional anomalies in the left supramarginal gyrus suggest a possible deficit in sensory feedback or integration. In LD, cortical and subcortical anomalies were reported in a widespread language network, with little consistency across studies except in the superior temporal gyri. In summary, both functional and structural anomalies are associated with LD and SD, including greater activity and volumes relative to controls. The variability in neuroimaging approach and heterogeneity within and across participant samples restricts our full understanding of the neurobiology of these conditions- reducing the potential for devising novel interventions targeted at the underlying pathology.
Human stem cells ameliorate auditory evoked responses in a model of neuropathy
(BIOMED CENTRAL LTD, 2012-11-08)
Stem cells have been touted as a potential source of replacement cells for the treatment of severe-to-profoundly deaf individuals, including possible combined therapy with a cochlear implant. The success of such a therapy is dependent on a number of factors, but of critical importance is the functional incorporation of transplanted cells into the peripheral and central auditory systems. In a major breakthrough, Chen and colleagues recently reported the restoration of hearing thresholds by up to 46% following the transplantation of human pluripotent stem cells in a rodent auditory neuropathy model. Improved function was matched with new synapse formation in the peripheral and central aspects of the auditory system. The findings have promising clinical implications for patients with auditory neuropathy. Still to be elucidated are the long-term survival and function of transplanted cells, the precise mechanism by which hearing is restored, and whether further improvement is possible when combined with electrical stimulation from a cochlear implant.
Eeyore: A Novel Mouse Model of Hereditary Deafness
(PUBLIC LIBRARY SCIENCE, 2013-09-23)
Animal models that recapitulate human disease are proving to be an invaluable tool in the identification of novel disease-associated genes. These models can improve our understanding of the complex genetic mechanisms involved in disease and provide a basis to guide therapeutic strategies to combat these conditions. We have identified a novel mouse model of non-syndromic sensorineural hearing loss with linkage to a region on chromosome 18. Eeyore mutant mice have early onset progressive hearing impairment and show abnormal structure of the sensory epithelium from as early as 4 weeks of age. Ultrastructural and histological analyses show irregular hair cell structure and degeneration of the sensory hair bundles in the cochlea. The identification of new genes involved in hearing is central to understanding the complex genetic pathways involved in the hearing process and the loci at which these pathways are interrupted in people with a genetic hearing loss. We therefore discuss possible candidate genes within the linkage region identified in eeyore that may underlie the deafness phenotype in these mice. Eeyore provides a new model of hereditary sensorineural deafness and will be an important tool in the search for novel deafness genes.
Effects of face masks on acoustic analysis and speech perception: Implications for peri-pandemic protocols
<jats:title>ABSTRACT</jats:title><jats:p>Wearing face masks (alongside physical distancing) provides some protection against infection from COVID-19. Face masks can also change how we communicate and subsequently affect speech signal quality. Here we investigated how three face mask types (N95, surgical and cloth) affect acoustic analysis of speech and perceived intelligibility in healthy subjects. We compared speech produced with and without the different masks on acoustic measures of timing, frequency, perturbation and power spectral density. Speech clarity was also examined using a standardized intelligibility tool by blinded raters. Mask type impacted the power distribution in frequencies above 3kHz for both the N95 and surgical masks. Measures of timing and spectral tilt also differed across mask conditions. Cepstral and harmonics to noise ratios remained flat across mask type. No differences were observed across conditions for word or sentence intelligibility measures. Our data show that face masks change the speech signal, but some specific acoustic features remain largely unaffected (e.g., measures of voice quality) irrespective of mask type. Outcomes have bearing on how future speech studies are run when personal protective equipment is worn.</jats:p>