Acoustic Measures of Phonation during Connected Speech in Adductor Spasmodic DysphoniaMichael P. Cannito1*, Eugene H. Buder1, Lesya B. Chorna1 and Richard Dressler2
- Corresponding Author:
- Michael P. Cannito, Ph.D.,
School of Communication Sciences and Disorders
The University of Memphis, 807 Jefferson Avenue
Memphis, Tennessee 38105
Tel: (901) 678 – 5847
Fax: (901) 525 – 1282
Received date: December 06, 2011; Accepted date: January 07, 2012; Published date: January 12, 2012
Citation: Cannito MP, Buder EH, Chorna LB, Dressler R (2012) Acoustic Measures of Phonation during Connected Speech in Adductor Spasmodic Dysphonia. Otolaryngol S1:003. doi:10.4172/2161-119X.S1-003
Copyright: © 2012 Cannito MP, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Objectives: This study examined acoustic measures related to voice production in connected speech of patients with adductor spasmodic dysphonia (ADSD) before and after boltulinum toxin (BT) treatment in comparison with speech of non-dysphonic healthy control (NHC) speakers. Correlations between acoustic measures and perceptual scaling judgments of overall voice quality were also examined.
Methods: Ten patients with moderate-to-severe ADSD were audio-recorded prior to and following BT injection, as were age and gender matched NHCs. Signal processing algorithms were employed to extract fundamental frequency (f 0 ) and intensity (dB) of speakers’ digitized oral readings. Control procedures minimized the influence of severely aperiodic phonation and obstruent consonant production on the analysis of modal f 0 and related variables such as signal-to-noise ratio (SNR). Measures of severe aperiodicity, with f 0 < 80 Hz, were compared with modal f 0 data. Perceptual judgments of voice quality were obtained from expert voice clinicians under rigorously controlled listening conditions.
Results: Acoustic measures of number of low frequency f 0 events, coefficient of variation of modal f 0 , and SNR demonstrated statistically significant differences for ADSD speech before and after treatment, and differentiated between ADSD and NHC speakers. Mean modal f 0 did not differentiate among speaker conditions. All other measures differentiated untreated ADSD speech from that of NHCs; however, only selected measures demonstrated differences between NHC and ADSD speakers following BT injection. Coefficient of variation of modal f 0 and SNR were moderately correlated with expert listener judgments of voice quality. Conclusion: Acoustic measures of connected speech derived from carefully edited modal f 0 tracks and intensity contours were effective for characterizing ADSD speech before and after treatment, and for differentiating it from that of NHCs. Acoustic measures were highly reliable and significantly related to voice quality scaling by expert listeners.