Introduction

Top Abstract Introduction Participants and methods Results Discussion References

Many patients have transient, self limiting changes in voice, but those who have been hoarse for more than three weeks need specialist assessment to exclude underlying laryngopharyngeal pathology. Once conditions that need surgery have been excluded, patients are usually referred to a speech and language therapist for voice therapy. Up to 40 000 patients with dysphonia are referred for voice therapy annually in the United Kingdom.¹ At the time of referral, many patients with vocal dysfunction have entered a vicious cycle in which psychological factors exacerbate voice pathology and poor voice quality adversely affects psychological wellbeing.^2-9

We aimed to examine the efficacy of voice therapy in patients with dysphonia and to identify those patients for whom voice therapy might be most beneficial.

	Participants and methods

Top Abstract Introduction Participants and methods Results Discussion References

We recruited consecutive outpatients attending the department of otorhinolaryngology and head and neck surgery of Glasgow Royal Infirmary with a primary complaint of dysphonia (hoarseness) present for a minimum of two months and without any relevant organic pathology (for example, polyp, papilloma, tumour, vocal cord palsy) or need for surgery.

The inclusion criteria were age greater than 16 years, motivation to resolve the voice problem, and willingness to enter into regular voice therapy sessions. The exclusion criteria were previously treated dysphonia, neurological disease, or upper aerodigestive tract malignancy; marked hearing impairment; acid reflux; multiple medical complaints; professional voice user requiring urgent intervention; puberphonia; and transsexual conflict.

Measures
PathophysiologyAn otolaryngologist (KMacK) used a flexible nasolaryngoscope to assess four featuresnodule formation, laryngitis, glottic escape, and hyperfunction of the laryngeal musculatureon a four point (0-3) rating scale.

Intervention
Baseline data were recorded after eligibility had been assessed and consent had been obtained. The participants were then seen by one speech and language therapist (CS), who obtained a number for random allocation of the participant to either a course of voice therapy or a period of observation. All voice therapy was delivered according to a protocol (see long version on bmj.com).¹⁶ Researchers involved in collecting outcome data were blind to details of the treatment. After six weeks of therapy or observation, data on pathophysiology, voice quality, psychological status, and quality of life were recorded. After a further 6-8 weeks, all measurements were repeated, and the clinical interview schedule was conducted.

Statistical analysis
Analysis of each outcome was conducted only on patients with complete data. Statistical analyses compared the mean difference in the outcome variables between the groups with and without treatment. We used an analysis of covariance procedure with group (treatment versus no treatment) as a between patients variable; we used people's baseline scores on the particular variable being compared as covariates for both the end of treatment and follow up analyses.

	Results

Top Abstract Introduction Participants and methods Results Discussion References

Of the 204 patients who gave informed consent for inclusion, 100 patients were randomised to voice therapy and 104 to no treatment. By completion of the study 12-14 weeks later, about a third of participants had dropped out or been excluded, leaving 70 patients in the treatment group and 63 patients in the observation group. As expected, most patients in both groups were women (50/72 (69%) in the control group and 56/73 (77%) in the treatment group); the groups were closely matched for age (mean (SD) age in the control group 52 (13) years and 51 (14) years in the treatment group). Laryngeal features at study entry were similar in the intervention and control patients. Grade 2-3 (moderate to severe) scores were uncommon for all of the four features, and only minimal resolution of the abnormalities occurred between the two time points.

The groups were well matched at entry to the study for subjective and objective voice variables. The treatment and no treatment groups differed at baseline only on the hospital anxiety and depression scale anxiety scores, which were higher in the control group. This difference between the treatment and no treatment groups was evident in the original 204 randomised recruits and in the 133 patients who completed all three phases of the study.

Effectiveness of voice therapy
By the end of treatment voice therapy significantly improved self rated quality of voice and the measurement of amplitude perturbation or "shimmer" by the Computerised Speech Laboratory. At follow up the patients in the treatment group had significantly lower scores than those in the no treatment group on the Buffalo overall rating and the voice profile questionnaire total score. Treatment effects (points) and 95% confidence intervals were calculated for each of the outcome variables at both completion of treatment and completion of follow up (tables 1 and 2). All participants with data at baseline and follow up were included. For the voice profile questionnaire the effect was 4.1 points (effect size 0.54 SD). For the Buffalo scale the effect was 0.82 points (effect size 0.76 SD). In conventional statistical terminology these are medium to large effects. Voice therapy had an effect on only one quality of life outcome variablemental health. This was significantly better in the treatment group at completion of treatment but not at completion of follow up.

	Discussion

Top Abstract Introduction Participants and methods Results Discussion References

This first randomised controlled trial of the efficacy of voice therapy for dysphonia has shown voice therapy to be effective in improving self rated and expert rated quality of voice. The magnitude of the observed mean improvements reflects clinically meaningful improvements in voice quality. The minimal change in laryngoscopic appearances during the study reflects the fact that many of the patients referred for non-surgical voice therapy have, by definition, relatively normal laryngeal appearances.

The voice therapy and no treatment groups were not significantly different in terms of either rate of attrition (30% in the therapy group, 39% in the no treatment group) or characteristics of patients who dropped out (sociodemographic variables or baseline voice or psychological variables). Thus, we believe that the attrition did not introduce bias.

Psychological distress was not significantly reduced as a result of treatment. Voice therapy had a significant effect on one quality of life variablemental healthat the end of treatment, but this was not maintained at follow up. A subgroup of patients remain psychologically distressed despite receiving treatment. Speech and language therapists often use psychological strategies but often acquire psychological training after qualification and in what has been described as an ad hoc manner.¹⁷ If patients with high psychological distress could be identified by screening they could be referred for psychological intervention, perhaps from a clinical psychologist.¹⁸

The disconcertingly abnormal SF-36 results highlight the importance of effective vocal communication for an individual's psychosocial wellbeing. Indeed, the level of psychological morbidity may also mainly reflect the greatly reduced quality of life in patients with dysphonia. Such interrelations underline the importance of a holistic treatment for reduction in symptoms and improvement in overall functioning.

	Acknowledgments

We acknowledge the contributions of Nicola Bradshaw and Shonagh Scott, who were both involved as research assistants in the collection of data for this paper; Dr Martha Whiteman for running the sensitivity analyses; Catherine Dunnet, chief speech and language therapist at Glasgow Royal Infirmary, for contributions to the project and comments on a draft of the paper; and Professor Stuart Gatehouse for his comments on an earlier draft of the paper.

	Footnotes

Funding: Scottish Office Home and Health Department (grant reference: K/RED/4/C249).

Competing interests: None declared. [Form not received yet]

The full version of this paper appears on the BMJ's website

	References

Top Abstract Introduction Participants and methods Results Discussion References

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(Accepted 8 July 2001)