Pathology - Research Publications

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    Vocal Acoustic Biomarkers of Depression Severity and Treatment Response
    Mundt, JC ; Vogel, AP ; Feltner, DE ; Lenderking, WR (ELSEVIER SCIENCE INC, 2012-10-01)
    BACKGROUND: Valid, reliable biomarkers of depression severity and treatment response would provide new targets for clinical research. Noticeable differences in speech production between depressed and nondepressed patients have been suggested as a potential biomarker. METHODS: One hundred five adults with major depression were recruited into a 4-week, randomized, double-blind, placebo-controlled research methodology study. An exploratory objective of the study was to evaluate the generalizability and repeatability of prior study results indicating vocal acoustic properties in speech may serve as biomarkers for depression severity and response to treatment. Speech samples, collected at baseline and study end point using an automated telephone system, were analyzed as a function of clinician-rated and patient-reported measures of depression severity and treatment response. RESULTS: Regression models of speech pattern changes associated with clinical outcomes in a prior study were found to be reliable and significant predictors of outcome in the current study, despite differences in the methodological design and implementation of the two studies. Results of the current study replicate and support findings from the prior study. Clinical changes in depressive symptoms among patients responding to the treatments provided also reflected significant differences in speech production patterns. Depressed patients who did not improve clinically showed smaller vocal acoustic changes and/or changes that were directionally opposite to treatment responders. CONCLUSIONS: This study supports the feasibility and validity of obtaining clinically important, biologically based vocal acoustic measures of depression severity and treatment response using an automated telephone system.
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    Speech acoustic markers of early stage and prodromal Huntington's disease: A marker of disease onset?
    Vogel, AP ; Shirbin, C ; Churchyard, AJ ; Stout, JC (PERGAMON-ELSEVIER SCIENCE LTD, 2012-12)
    Speech disturbances (e.g., altered prosody) have been described in symptomatic Huntington's Disease (HD) individuals, however, the extent to which speech changes in gene positive pre-manifest (PreHD) individuals is largely unknown. The speech of individuals carrying the mutant HTT gene is a behavioural/motor/cognitive marker demonstrating some potential as an objective indicator of early HD onset and disease progression. Speech samples were acquired from 30 individuals carrying the mutant HTT gene (13 PreHD, 17 early stage HD) and 15 matched controls. Participants read a passage, produced a monologue and said the days of the week. Data were analysed acoustically for measures of timing, frequency and intensity. There was a clear effect of group across most acoustic measures, so that speech performance differed in-line with disease progression. Comparisons across groups revealed significant differences between the control and the early stage HD group on measures of timing (e.g., speech rate). Participants carrying the mutant HTT gene presented with slower rates of speech, took longer to say words and produced greater silences between and within words compared to healthy controls. Importantly, speech rate showed a significant correlation to burden of disease scores. The speech of early stage HD differed significantly from controls. The speech of PreHD, although not reaching significance, tended to lie between the performance of controls and early stage HD. This suggests that changes in speech production appear to be developing prior to diagnosis.
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    Longitudinal change in dysarthria associated with Friedreich ataxia: a potential clinical endpoint
    Rosen, KM ; Folker, JE ; Vogel, AP ; Corben, LA ; Murdoch, BE ; Delatycki, MB (SPRINGER HEIDELBERG, 2012-11)
    CNS functions that show change across short periods of time are particularly useful clinical endpoints for Friedreich ataxia. This study determined whether there is measurable acoustical change in the dysarthria associated with Friedreich ataxia across yearly intervals. A total of 29 participants diagnosed with Friedreich ataxia were recorded across 4 years at yearly intervals. A repeated measures ANOVA was used to determine which acoustic measures differed across time, and pairwise t tests were used to assess the consistency of the change across the time intervals. The relationship between the identified measures with perceptual severity was assessed with stepwise regression. Significant longitudinal change was observed with four measures that relate to the utterance duration and spectral changes in utterances. The spectral measures consistently detected change across time intervals of two or more years. The four measures combined moderately predicted perceptual severity. Together, the results implicate longitudinal change in speaking rate and utterance duration. Changes in speech associated with Friedreich ataxia can be measured across intervals of 2 years and therefore show rich potential for monitoring disease progression and therapy outcomes.
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    Monitoring change requires a rethink of assessment practices in voice and speech
    Vogel, AP ; Maruff, P (TAYLOR & FRANCIS LTD, 2014-07)
    Assessment for the purpose of monitoring change over time requires a different practical and statistical approach to that of assessment for diagnosing impairment. Sophisticated methods exist for identifying strengths and weaknesses in a patient's voice/speech profile, yet our understanding of the impact of repeated assessment is limited. Monitoring change necessitates that stimuli are stable in the absence of any true change in functioning, while remaining sensitive to influences that are considered to alter functioning (degeneration, therapy). The current paper discusses the issues relating to stimuli selection, identifying error within the sample and appropriate statistical models for identifying intra-individual change in the context of clinical and experimental speech or voice examinations.