Teachers With Voice Disorders: Recent Clinical Trials Research Approximately 10% of the workforce in the United States would be classified as “heavy occupational voice users.” However, this country’s 3.3 million elementary and secondary school teachers represent the largest group of professionals who use their voice as a primary tool of trade. Recent epidemiological evidence has confirmed that voice ... Features
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Features  |   April 01, 2005
Teachers With Voice Disorders: Recent Clinical Trials Research
Author Notes
  • Roy Nelson, is associate professor in the Department of Communication Sciences and Disorders at the University of Utah.
    Roy Nelson, is associate professor in the Department of Communication Sciences and Disorders at the University of Utah.×
Article Information
Speech, Voice & Prosodic Disorders / Voice Disorders / Features
Features   |   April 01, 2005
Teachers With Voice Disorders: Recent Clinical Trials Research
The ASHA Leader, April 2005, Vol. 10, 8-11. doi:10.1044/leader.FTR6.10052005.8
The ASHA Leader, April 2005, Vol. 10, 8-11. doi:10.1044/leader.FTR6.10052005.8
Approximately 10% of the workforce in the United States would be classified as “heavy occupational voice users.” However, this country’s 3.3 million elementary and secondary school teachers represent the largest group of professionals who use their voice as a primary tool of trade.
Recent epidemiological evidence has confirmed that voice disorders are a common occupational hazard of teaching school, with 11% of teachers reporting a current voice disorder, and 58% experiencing a voice disorder during their career. Furthermore, these voice disorders adversely affect job performance and attendance, with 43% of teachers having to reduce classroom activities, and 18% of teachers missing work on a yearly basis because of voice-related problems. Because of lost workdays and treatment expenses, the societal costs-in the U.S. alone-have been estimated to be nearly $2.5 billion annually.
One explanation for the increased frequency of voice disorders in teachers relates to the voice demands of teaching school. In a predisposed teacher, vocal fold injury can occur if a critical “vibration dose” is exceeded. Many teachers speak loudly for long periods without sufficient time for vocal fold tissue to recover. This likely contributes to vibration overdose. In clinical circles, the desire to limit or reduce a teacher’s vibration dose (i.e., vocal load) has been the guiding principle underlying many voice therapy approaches. However, little was known until recently regarding which voice therapy approach was effective.
Randomized Clinical Trials
Over the past four years, voice researchers from several institutions have collaborated to conduct randomized clinical trials (RCT) research designed to assess the efficacy of specific voice treatment approaches. This collaborative effort produced three RCTs using teachers with voice disorders as participants. In all three trials, the teachers with voice disorders were randomly assigned to one group (a treatment or a control group).
Teachers were seen on only four occasions during a six-week treatment phase by SLPs who were trained in the various therapy approaches. Each teacher completed the Voice Handicap Index (VHI)-an instrument designed to appraise the self-perceived psychosocial consequences of voice disorders-before and following the six-week treatment period.
In the first RCT, vocal hygiene (VH) instruction, vocal function exercises (VFE) and a non-treatment control group were compared. In contrast to the VH approach, VFEs claim to strengthen and rebalance the subsystems involved in voice production through a program of systematic exercise. The results of this clinical trial showed that only the group who exercised their voice reported a significant benefit (i.e., significantly reduced VHI scores). The authors seriously questioned the effectiveness of VH instruction alone as a broad-spectrum voice therapy approach.
In the second RCT, portable voice amplification (VA) and VH instruction were compared. By providing increased loudness, the voice amplifier might reduce the teacher’s vibration dose. Pre- and post-treatment comparisons revealed that only the amplification group experienced significant reductions on mean VHI scores. The non-treatment control group reported a significant deterioration in voice as assessed by the VHI.
In the final RCT, the effects of Resonant Voice or Resonance Therapy (RT) were compared to VA and Respiratory Muscle Training (RMT). RT involves training the teacher with a voice disorder to produce voice with a “forward/frontal tone focus” which accentuates mid-facial vibratory sensations. The objective of RT is to achieve a strong voice with minimal vocal fold impact stress.
RMT attempts to strengthen the expiratory muscles in order to help patients with voice disorders increase their ability to generate expiratory pressures. By improving the strength of the expiratory muscles, the burden on the larynx is presumably lessened-with a reduction in compensatory hyperfunctional laryngeal behavior and reduced tissue trauma. To accomplish RMT, a pressure threshold device is used which demands increasing levels of expiratory muscle strength.
Analysis of the results revealed that only the teachers who received VA or RT reported significant reductions on mean VHI scores. These findings replicated previous results from the earlier clinical trial confirming the efficacy of amplification, and provide new evidence to support RT as an effective treatment alternative for voice problems in teachers.
In summary, recent epidemiological and randomized clinical trials research not only highlights the scale and deleterious effects of teaching-related voice disorders, but provides much needed evidence for SLPs regarding the most effective treatments.
References
Roy, N., Merrill, R., Thibeault, S., Parsa, R., Gray, S., & Smith, E. (2004). Prevalence of voice disorders in teachers and the general population. Journal of Speech, Language, and Hearing Research, 47 (2), 281–293. [Article]
Roy, N., Merrill, R., Thibeault, S., Parsa, R., Gray, S., & Smith, E. (2004). Prevalence of voice disorders in teachers and the general population. Journal of Speech, Language, and Hearing Research, 47 (2), 281–293. [Article] ×
Roy, N., Merrill, R., Thibeault, S., Gray, S., & Smith, E. (2004). Voice disorders in teachers and the general population: Effects on work performance, attendance, and future career choices. Journal of Speech, Language, and Hearing Research, 47 (3), 542–551. [Article]
Roy, N., Merrill, R., Thibeault, S., Gray, S., & Smith, E. (2004). Voice disorders in teachers and the general population: Effects on work performance, attendance, and future career choices. Journal of Speech, Language, and Hearing Research, 47 (3), 542–551. [Article] ×
Roy, N., Gray, S.D., Ebert, M. Dove, H., Corbin-Lewis, K., & Stemple, J.C. (2001). An evaluation of the effects of two treatments for teachers with voice disorders: A prospective randomized clinical trial. Journal of Speech, Language, and Hearing Research, 44 (2), 286–296. [Article]
Roy, N., Gray, S.D., Ebert, M. Dove, H., Corbin-Lewis, K., & Stemple, J.C. (2001). An evaluation of the effects of two treatments for teachers with voice disorders: A prospective randomized clinical trial. Journal of Speech, Language, and Hearing Research, 44 (2), 286–296. [Article] ×
Roy, N., Weinrich, B., Gray, S.D., Tanner, K., Walker-Toledo, S., Dove, H., Corbin-Lewis, K., & Stemple, J. (2002). Voice amplification versus vocal hygiene instruction for teachers with voice disorders: A treatment outcomes study. Journal of Speech, Language, and Hearing Research, 45 (4), 625–638. [Article]
Roy, N., Weinrich, B., Gray, S.D., Tanner, K., Walker-Toledo, S., Dove, H., Corbin-Lewis, K., & Stemple, J. (2002). Voice amplification versus vocal hygiene instruction for teachers with voice disorders: A treatment outcomes study. Journal of Speech, Language, and Hearing Research, 45 (4), 625–638. [Article] ×
Roy, N., Weinrich, B., Gray, S.D., Tanner, K., Stemple, J., & Sapienza, C. (2003). Three treatments for teachers with voice disorders: A randomized clinical trial. Journal of Speech, Language, and Hearing Research, 46 (3), 670–688. [Article]
Roy, N., Weinrich, B., Gray, S.D., Tanner, K., Stemple, J., & Sapienza, C. (2003). Three treatments for teachers with voice disorders: A randomized clinical trial. Journal of Speech, Language, and Hearing Research, 46 (3), 670–688. [Article] ×
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April 2005
Volume 10, Issue 5