Replication, Randomization, and Clinical Relevance A Response to Dworkin and Colleagues (2004) Letter to the Editor
Letter to the Editor  |   April 01, 2004
Replication, Randomization, and Clinical Relevance
 
Author Affiliations & Notes
  • Nelson Roy
    The University of Utah, Salt Lake City, UT
  • Barbara Weinrich
    Miami University, Oxford, OH
  • Kristine Tanner
    The University of Utah, Salt Lake City, UT
  • Kim Corbin-Lewis
    Utah State University, Logan, UT
  • Joseph Stemple
    The Blaine Block Institute for Voice Analysis and Rehabilitation, Dayton, OH
  • Corresponding author: e-mail: nelson.roy@health.utah.edu
  • Contact author: Nelson Roy, PhD, Department of Communication Sciences and Disorders, The University of Utah, 390 South 1530 East, Room 1219, Salt Lake City, UT 84112-0252. E-mail: nelson.roy@health.utah.edu
Article Information
Speech, Voice & Prosodic Disorders / Voice Disorders / Hearing & Speech Perception / Acoustics / Speech, Voice & Prosody / Speech / Letters to the Editor
Letter to the Editor   |   April 01, 2004
Replication, Randomization, and Clinical Relevance
Journal of Speech, Language, and Hearing Research, April 2004, Vol. 47, 358-365. doi:10.1044/1092-4388(2004/029)
History: Received October 23, 2003 , Accepted October 31, 2003
 
Journal of Speech, Language, and Hearing Research, April 2004, Vol. 47, 358-365. doi:10.1044/1092-4388(2004/029)
History: Received October 23, 2003; Accepted October 31, 2003
Web of Science® Times Cited: 3
We welcome the opportunity to respond to the recent letter to JSLHR from Dworkin, Abkarian, Stachler, Culatta, and Meleca (2004)  wherein they questioned the strength of our evidence to support the effectiveness of voice amplification for teachers with voice disorders (as shown in Roy et al., 2002). Our first response is to make Dworkin and coauthors aware of another recently published randomized clinical trial by our group wherein the significant treatment results obtained with voice amplification (VA) in this study were replicated using a larger and entirely different group of teachers with voice disorders (Roy et al., 2003). In brief, we enrolled another 87 teachers with voice disorders, then randomly assigned them to one of three treatment groups: voice amplification (VA), resonance therapy (RT), and respiratory muscle training (RMT). Inspection of the results revealed that only the VA and RT groups reported significant reductions in mean Voice Handicap Index (VHI; Jacobson et al., 1997) scores and in voice severity self-ratings following treatment. Furthermore, results from the identical posttreatment questionnaire regarding the perceived benefits of treatment showed that compared to the other two treatment groups, teachers in the amplification group reported significantly more overall improvement, greater vocal clarity, and greater ease of speaking and singing. When one compares the results from our original investigation with the subsequent replication study, the similarity of the results observed for the VA group in these two studies is both striking and confirmatory. Indeed, many of the concerns expressed by Dworkin et al. regarding the robustness, repeatability, and validity of the positive results obtained for the VA group in the first study are answered by this replication study. Muma (1993)  suggested that “replicated results not only become factual but constitute substantiation and verification functions for research that extend external validity” (p. 927). Thus, in light of this replication, we find it highly unlikely that the positive treatment outcomes demonstrated by the VA group in the original study were somehow spurious or related to any of the measurement or methodological issues raised by Dworkin and colleagues in their critique. The more likely, and reasonable, conclusion is that the results from both studies are valid and reflect actual treatment gains made by each of these groups of voice-disordered teachers. In short, we feel secure in responding to Dworkin and colleagues’ title question, “Is voice amplification for teachers with dysphonia really beneficial?” with an unequivocal “Yes.”
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