Roy, et al. 2002. J Speech Lang Hear Res.

Paper: N. Roy, B. Weinrich, S. D. Gray, K. Tanner, S. W. Toledo, H. Dove, K. Corbin-Lewis, and J. C. Stemple. Voice amplification versus vocal hygiene instruction for teachers with voice disorders: a treatment outcomes study. Journal of Speech, Language, & Hearing Research 45 (4):625-638, 2002.

Link to PubMed and abstract: PMID 12199394

First Commented on April 11, 2007

General Comments: This is an interesting example as this paper is cited often since it deals with teachers voice, etc. and it has already been challenged in the literature with a letter to the editor and then a response from the original authors:

J. P. Dworkin, G. G. Abkarian, R. J. Stachler, R. A. Culatta, and R. J. Meleca. Is voice amplification for teachers with dysphonia really beneficial? J.Speech Lang Hear.Res. 47 (2):353-357, 2004. author reply 358-65.

What I found interesting was that the only question I had with the paper had nothing to do with the letter to the editor and the response (I didn't think the Roy response was all that convincing anyway). Nevertheless, my own question is below.

First Comment: The authors use a voice indexing measure called the VHI (Voice Handicap Index) developed and discussed in the article below:

Barbara H. Jacobson, A. Johnson, Cynthia Grywalski, Alice K. Silbergleit, G. P. Jacobson, Michael S. Benninger, and C. W. Newman. The voice handicap index (VHI): development and validation. American Journal of Speech-Language Pathology 6 (3):66-70, 1997

In the Jacobson 1997 article, they develop the statistics by showing that a change of 18 points in the scale represent a significant change in the function of the voice. This is done by controlling repeated uses of the scale both within and across subjects. When Roy et al 2002 uses the VHI, they disregarded this completely. Roy et al discuss significant difference but they seemed to have miss used the VHI, thus potentially invalidating their entire conclusion set.

Final Comments: I would hope the Roy group addressed this since their study is often cited. This oversight could be severe.