Audiology and Speech Pathology - Research Publications

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Author: VOGEL, ADAM × End date: 2009 × Start date: 2009 ×

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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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    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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    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.