Lasting effects seen in three-year study of people with spasmodic dysphonia
ANN ARBOR, MI -- An injection that's best known for smoothing wrinkles also helps restore the voices -- and the confidence -- of people with a voice disorder caused by spasms in their vocal cord muscles, a new University of Michigan study finds.
Botulinum toxin type A, known as Botox, has been used off-label for years to help people with spasmodic dysphonia, a rare and often-misdiagnosed voice disorder that makes the voice sound strained, broken or breathy. The shots relax the muscles in the vocal cords, just as they do to the muscles in the furrowed foreheads of those who use Botox for cosmetic reasons.
But until now, no long-term data have been available on how the repeated injections affect both patients' voices, and the emotional, social and physical functioning issues that collectively make up what experts call voice-related quality of life, or V-RQOL. Those answers are being published by a team from the U-M Health System's Vocal Health Center and Department of Otolaryngology -- and the effect is striking.
In the April issue of the Archives of Otolaryngology, Head and Neck Surgery, the team reports results from a prospective study of 36 patients with the adductory form of spasmodic dysphonia who were treated with Botox up to six times.
Nearly all showed dramatic and reproducible improvement on a standardized questionnaire that measured their V-RQOL. On a scale of 100, with 100 being perfect, the patients went from an average score of 30 before the first injection to an average score of around 80 afterward.
Patients entered the study at the time of their diagnosis with spasmodic dysphonia, and began treatment soon after. Following an initial injection, they returned for re-injection when their voice symptoms had gradually come back. The average time between injections for study participants was 25 weeks. The biggest jump in scores occurred from baseline to after the first treatment. But even after six injections, the difference between pre-treatment and post-treatment V-RQOL scores was large.
The result counters previous suspicions that the effect of Botox diminishes after repeated injections. It also shows that when it comes to the very personal, subjective issue of how a voice problem affects a person's well-being, the injections produce a powerful and sustained improvement.
"We now have good evidence that this treatment does have a significant and repeatable beneficial effect on the voice-related quality of life, and that we can make objective measures of an otherwise subjective treatment effect," says senior author Norman D. Hogikyan, M.D., director of the UMHS Vocal Health Center.
"The voice means different things to different people, which is why we developed and validated a standardized tool to measure changes," adds Hogikyan, an associate professor at the U-M Medical School and in the Division of Vocal Arts at the U-M School of Music.
Hogikyan, who has administered Botox to voice patients for nearly 10 years and provides Botox therapy to about 20 spasmodic dysphonia patients a month, notes that the study relied on a Voice-Related Quality of Life measure he developed in conjunction with U-M School of Public Health researchers in the late 1990s.
The V-RQOL questionnaire asks the patients to think about the past two weeks and choose a level of agreement with each of 10 statements, ranging from 1 (not a problem) to 5 (the problem is 'as bad as it can be'). The statements include everything from "I have trouble speaking loudly or being heard in noisy situations" to "I avoid going out socially (because of my voice)." In the study, the responses were turned into a total score of 1 through 100 using an algorithm, and also as two sub-scores indicating physical and social/emotional impacts of the voice disorder.
The researchers also asked patients to give an overall rating of their voice, of excellent, very good, good, fair or poor. This allowed them to look at categorical improvement -- for example, a patient who gave herself a "poor" rating before a Botox injection, and then gave herself a "good" overall rating several weeks after her injection, would have a categorical improvement of +2.
The new study is based on pre- and post-injection V-RQOL results from each patient's initial Botox injection, given during office visits, and on results from questionnaires mailed to patients a month or so after subsequent injection visits where they completed the pre-treatment questionnaire again. Six patients who chose not to receive Botox injections were also given the questionnaire during an initial office visit.
The patients' average age was 51, and 85 percent were female, reflecting spasmodic dysphonia's general incidence patterns.
At the outset, the patients' average score on the 100-point V-RQOL scale was very low -- 32.7. After their first treatment, the average score shot up to 80.6. "This reflects a significant improvement in their state of mind about speaking, and their physical ability to speak," says Hogikyan.
During the study period, 23 of the patients had a second Botox injection, 14 of those had a third and fourth, 11 of those 14 had five injections, and five of those 11 patients had six injections. The number of injections a particular patient had was primarily based upon the point in the study period when they were diagnosed and started on treatment. All patients newly diagnosed with spasmodic dysphonia at the U-M during the three-year study period are included in the study.
There was significant improvement in scores on the 100-point scale with each successive treatment, although the size of the jump was not as big as it had been with the first injection. The degree of improvement was stable over the third through sixth injections. Thirty of the patients are still receiving injections at U-M about twice a year.
Overall, 97 percent of the patients' pre-injection self-assessments rated their voice as poor or fair, but 74 percent of the post-injection assessments said their voices were good to excellent. Eighty percent of injections resulted in at least one categorical improvement in voice rating. The categorical changes in ratings corresponded well with changes in V-RQOL scores;
Previous studies by Hogikyan and others have shown the V-RQOL tool to be reliable and easy for patients to complete. But he notes that the new data reaffirm its validity in assessing treatment outcomes in voice disorders, which has typically been a hard thing to do because of difficulty in quantifying voice problems.
Mainly, though, Hogikyan and his colleagues are pleased that the patients enjoyed a significant and reproducible benefit from the Botox injections. They also note that the patients' expectations might explain the smaller jumps in V-RQOL scores after the second through sixth injections.
"After the initial treatment, patients may begin to think about their vocal capabilities relative to normal voices around them, and may come for their subsequent injections before the situation gets as critical as the first time," says Hogikyan. "We think perceptions stabilize after a few injections."
In addition to Hogikyan, the study's authors include Adam D. Rubin, M.D., Walter Wodchis, Ph.D., of the Toronto Rehabilitation Institute; Constance Spak, M.A.; and Paul Kileny, Ph.D. The development of the V-RQOL instrument used U-M funding in the 1990s; the current research was funded internally. None of the authors has any financial interest in Botox or its manufacturers.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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