Audiology and Speech Pathology - Research Publications

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    A Comparative Study of Two Acoustic Measures of Hypernasality
    Vogel, AP ; Ibrahim, HM ; Reilly, S ; Kilpatrick, N (AMER SPEECH-LANGUAGE-HEARING ASSOC, 2009-12-01)
    PURPOSE: This study aimed to compare 2 quantitative acoustic measures of nasality in children with cleft lip and palate (CLP) and healthy controls using formalized perceptual assessment as a guide. METHOD: Fifty participants (23 children with CLP and 27 age- and gender-matched healthy controls) aged between 4 and 12 years produced a variety of high and low vowels that allowed perceptual ratings of nasal resonance severity as well as acoustic analysis of spectral changes. Two objective measures of nasality were used: 1/3 octave spectra analysis and the voice low tone high tone ratio. Each respective technique has been evaluated in previous research, and their potential as an effective means of detecting changes in nasal resonance has been demonstrated. RESULTS: Only 1/3 octave spectra analysis differentiated between participants with hypernasal speech and those perceived to have normal nasal resonance. Significant differences were also observed between varying levels of perceived severity on vowels within nonnasalized phonemic environments (/pIt/, /tIp/). CONCLUSIONS: Perceptual judgment remains the primary means of evaluating levels of nasality in children with CLP. However, the development and validation of easy-to-use objective techniques remains an important goal for effective clinical and empirical practice.
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    Factors affecting the quality of sound recording for speech and voice analysis
    Vogel, AP ; Morgan, AT (INFORMA HEALTHCARE, 2009-12)
    The importance and utility of objective evidence-based measurement of the voice is well documented. Therefore, greater consideration needs to be given to the factors that influence the quality of voice and speech recordings. This manuscript aims to bring together the many features that affect acoustically acquired voice and speech. Specifically, the paper considers the practical requirements of individual speech acquisition configurations through examining issues relating to hardware, software and microphone selection, the impact of environmental noise, analogue to digital conversion and file format as well as the acoustic measures resulting from varying levels of signal integrity. The type of recording environment required by a user is often dictated by a variety of clinical and experimental needs, including: the acoustic measures being investigated; portability of equipment; an individual's budget; and the expertise of the user. As the quality of recorded signals is influenced by many factors, awareness of these issues is essential. This paper aims to highlight the importance of these methodological considerations to those previously uninitiated with voice and speech acoustics. With current technology, the highest quality recording would be made using a stand-alone hard disc recorder, an independent mixer to attenuate the incoming signal, and insulated wiring combined with a high quality microphone in an anechoic chamber or sound treated room.
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    Comparison of voice acquisition methodologies in speech research
    Vogel, AP ; Maruff, P (SPRINGER, 2008-11)
    The use of voice acoustic techniques has the potential to extend beyond work devoted purely to speech or vocal pathology. For this to occur, however, researchers and clinicians will require acquisition technologies that provide fast, accurate, and cost-effective methods for recording data. Therefore, the present study aimed to compare industry-standard techniques for acquiring high-quality acoustic signals (e.g., hard drive and solid-state recorder) with widely available and easy-to-use, computer-based (standard laptop) data-acquisition methods. Speech samples were simultaneously acquired from 15 healthy controls using all three methods and were analyzed using identical analysis techniques. Data from all three acquisition methods were directly compared using a variety of acoustic correlates. The results suggested that selected acoustic measures (e.g., f 0, noise-to-harmonic ratio, number of pauses) were accurately obtained using all three methods; however, minimum recording standards were required for widely used measures of perturbation.
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    Verbal Fluency, Semantics, Context and Symptom Complexes in Schizophrenia
    Vogel, AP ; Chenery, HJ ; Dart, CM ; Doan, B ; Tan, M ; Copland, DA (SPRINGER/PLENUM PUBLISHERS, 2009-10)
    Lexical-semantic access and retrieval was examined in 15 adults diagnosed with schizophrenia and matched controls. This study extends the literature through the inclusion of multiple examinations of lexical-semantic production within the same patient group and through correlating performance on these tasks with various positive and negative clinical symptoms. On tasks of verbal fluency, meaning generation, sentence production using contextual information and confrontation naming, participants with schizophrenia made significantly more semantic errors on naming tasks; produced fewer meanings for homophones; produced fewer items on semantic, phonological, cued and switching fluency tasks; and produced more errors on sentence production tasks when compared to healthy controls. Significant correlations were also observed between ratings of psychomotor poverty and measures of semantic production and mental inflexibility. This study has provided additional evidence for deficits in lexical-semantic retrieval which are not due to underlying semantic store degradation, do not involve phonological based retrieval, and at the level of sentence generation appear to vary as a function of the contextual constraints provided.
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    Intervention for developmental apraxia of speech (Protocol)
    Morgan, A ; Vogel, A ; Morgan, A (Wiley - John Wiley & Sons, 2006-12-01)
    This is the protocol for a review and there is no abstract. The objectives are as follows: To assess the efficacy of intervention for developmental apraxia of speech / developmental verbal dyspraxia. Copyright © 2006 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
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    Intervention for dysarthria associated with acquired brain injury in children and adolescents (Review)
    Morgan, AT ; Vogel, AP (Wiley - John Wiley & Sons, 2008)
    BACKGROUND:The term 'acquired brain injury' (ABI) incorporates a range of aetiologies including cerebrovascular accident, brain tumour and traumatic brain injury. ABI is a common cause of disability in the paediatric population, and dysarthria is a common and often persistent sequelae associated with ABI in children. OBJECTIVES:To assess the efficacy of intervention delivered by Speech and Language Pathologists/Therapists targeting dysarthric speech in children resulting from acquired brain injury. SEARCH STRATEGY:We searched CENTRAL (Issue 4, 2006), MEDLINE (1966 to 02/2007), CINAHL (1982 to 02/2007), EMBASE (1980 to 02/2007), ERIC (1965 to 02/2007), Linguistics Abstracts Online (1985 to 02/07), PsycINFO (1872 to 02/2007). Additional references were also sought from reference lists studies. SELECTION CRITERIA:The review considered randomised controlled trials (RCTs) and quasi-experimental design studies of children aged 3-16 years with acquired dysarthria grouped by aetiology (e.g., brain tumour, traumatic brain injury, cerebrovascular accident). DATA COLLECTION AND ANALYSIS:Each author independently assessed the titles and abstracts for relevance (100% inter-rater reliability) and the full text version of all potentially relevant articles was obtained. No studies met inclusion criteria. MAIN RESULTS:Of 2091 titles and abstracts identified, full text versions of only three (Morgan 2007; Murdoch 1999; Netsell 2001) were obtained. 2088 were excluded, largely on the basis of not including dysarthria, being diagnostic or descriptive papers, and for concerning adults rather than children. Morgan 2007 and Murdoch 1999 were excluded for not employing RCT or quasi-randomised methodology; Netsell 2001 on the basis of being a theoretical review paper, rather than an intervention study. Five references were identified and obtained from the bibliography of the Murdoch 1999 paper. All were excluded due to including populations without ABI, adults with dysarthria, or inappropriate design. Thus, no studies met inclusion criteria. AUTHORS' CONCLUSIONS:The review demonstrates a critical lack of studies, let alone RCTs, addressing treatment efficacy for dysarthria in children with ABI. Possible reasons to explain this lack of data include i) a lack of understanding of the characteristics or natural history of dysarthria associated with this population; ii) the lack of a diagnostic classification system for children precluding the development of well targeted intervention programs; and iii) the heterogeneity of both the aetiologies and resultant possible dysarthria types of paediatric ABI. Efforts should first be directed at modest well-controlled studies to identify likely efficacious treatments that may then be trialed in multi-centre collaborations using quasi-randomised or RCT methodology.
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    The voice as a behavioural probe of emotional/neurophysiological disorders
    Vogel, A (The Speech Pathology Association of Australia Ltd., 2008)
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    Standardization of pitch-range settings in voice acoustic analysis
    Vogel, AP ; Maruff, P ; Snyder, PJ ; Mundt, JC (PSYCHONOMIC SOC INC, 2009-05)
    Voice acoustic analysis is typically a labor-intensive, time-consuming process that requires the application of idiosyncratic parameters tailored to individual aspects of the speech signal. Such processes limit the efficiency and utility of voice analysis in clinical practice as well as in applied research and development. In the present study, we analyzed 1,120 voice files, using standard techniques (case-by-case hand analysis), taking roughly 10 work weeks of personnel time to complete. The results were compared with the analytic output of several automated analysis scripts that made use of preset pitch-range parameters. After pitch windows were selected to appropriately account for sex differences, the automated analysis scripts reduced processing time of the 1,120 speech samples to less than 2.5 h and produced results comparable to those obtained with hand analysis. However, caution should be exercised when applying the suggested preset values to pathological voice populations.