149 Voice Disorders

Efficacy for speech and language therapy for dysphonia

MARGARET GORDON The Victoria Infirmary NHS Trust, Scotland MYRA LOCKHART Lanarkshire Healthcare NHS Trust, Scotland

ABSTRACT In order to establish efficacy of any type of interuention for a func- tional disordec it is necessary to eualuate the function before and after treatment and to haue confidence in the measurements used. Vocal function has many param- eters which require the employment of different tests for reliable assessment. The validity of these tests needs to be established by systematic literature review and, where possible, formal meta-analysis. The US Agency for Health Care Policy and Research (US-AHCPR) has recommended a method of grading euidence for use in the deuelopment of guidelines (AHCPR, 1992) and a similar method could be em- ployed to eualuate the reliability of uocal function tests. Hirano ( I 989) presented the results of a survey carried out to identify the type, nature, aim and frequency of use of clinical voice eualuation procedures and also reviewed the results of the procedures used in his own department in Kurume, and their reliability in measur- ing parameters of uocal function. Hirano (1 989) made suggestions and recommen- dations for useful measurements, including perceptual eualuation, visual inspec- tion, tape-recording, stroboscopy, Fo measurements, sound pressure, level meas- urement, aerodynamic tests and acoustic tests. A standard, using the GRBAS scale, has been suggested by the IALP Voice Committee for perceptual eualuations, but no standards haue yet been agreed for the remaining tests. This paper looks at some of the euidence for assessment standard setting and at reported efficacy stud- ies which haue used these assessments for monitoring outcomes.

INTRODUCTION

In order to establish efficacy of any type of intervention for a disorder of motility or function, it is necessary to evaluate the function before and after treatment and to have confidence in the measurements used. In many ways, vocal function lends itself to this approach as there are many parameters which can be measured. These parameters, however, require the employment of different tests for reliable assessment. The tests, in turn, need to have their validity established by systematic literature review and, where possible, formal meta-analysis. It is also important that we do not overlook the un- known psychological influence.

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METHOD

A literature search was carried out to establish the validity of various assessment proce- dures used in measuring perceived voice change and/or physiological change in voice production, and to examine studies reported to measure outcomes of voice therapy with respect to:

The design of the study. The assessment procedures used. A description of intervention. Reported outcomes. The effect of psychological factors.

A Medline search of the past 20 years was supplemented by a search of various journals, books and conference proceedings and produced only 52 relevant publica- tions in English. These studies were then subdivided into the following:

Those designed to validate assessment tools - 20 papers (38%). Those concerned with efficacy of surgical intervention - eight papers (15%). Those concerned with efficacy of therapy - 12 papers (23%). Those regarding validation of assessment tools and of therapy - six papers (1 1.5%). Those regarding efficacy of surgical intervention and of therapy - six papers (1 1.5%).

Since any study of efficacy needs to be evidence based, these studies were examined according to the criteria suggested by the US Agency for Health Care Policy and Re- search (US-AHCPR) which has been endorsed by the Scottish Intercollegiate Guide- lines Network (SIGN), as relevant in the establishing of national guidelines. The US- AHCPR grades the evidence presented according to the type, scope and design of the study and grades them A, B or C, accordingly.

Grade A evidence is obtained from meta-analysis of randomised controlled trials or from at least one randomised controlled trial. Grade B evidence is obtained from at least one well-designed controlled study without randomisation or from at least one other type of well-designed quasi-experimental study or from well-designed non-experi- mental descriptive studies, such as comparative studies, correlation studies and case studies. Grade C evidence is obtained from expert committee reports or opinions and/ or clinical experiences of respected authorities.

It is important to note that grading is not an assessment of the value of the study, but simply that a C grade based on opinion, albeit highly expert, does not carry the weight of evidence of a Grade A study.

RESULTS

The grading of the papers showed the following results. Those designed to validate assessment tools revealed three at Grade A, nine at Grade B, and eight at Grade C. Examples of A, B and C studies, respectively, would be:

Grade A Objective Evaluation of the Human Voice: Clinical Aspects (Hirano, 1989).

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Grade B The Quantitatiue Analysis of Dysphonia (Sanderson & Maran, 1992). Grade C Recommendations of the Union of European Phoniatricians (UEP): Standardising Voice Area Measuremenflhonetography (Schutte & Seidner, 1983).

Recognising the need for agreed assessments and procedures, Hirano (1989) car- ried out a worldwide survey of clinical voice evaluation using a questionnaire and the results of the Department of Otolaryngology at Kurume University Hospital, Japan. This was a large survey and involved meta-analysis. Similarly, the results from Kurume University involved a large sample from over many years, and use of established and standardised procedures. This study is examined in more detail later as it gives impor- tant recommendations for the future.

In efficacy of surgical intervention there was one Grade A study, five Grade B studies, and two Grade C studies. There were many different topics covered by these studies, examples being those involving granuloma, botulinum toxin injection and vocal polyps and nodules:

Grade A Contact Granuloma in the Larynx - Associated with Voice Deuia- tion (Alenbratt, Rydell & Schalen, 1995). Grade B Botulinum Toxin Injection for Adductor Spasmodic Dysphonia (Aronson et al., 1993). Grade C Vocal Polyps and Nodules (Harma et al., 1975).

In efficacy of therapy there were two Grade A studies, six Grade B, and four Grade C studies, an example of each being:

Grade A An Eualuation of Voice Therapy in Non-Organic Dysphonia (Carding & Horsely, 1992). Grade B Results of Vocal Therapy for Phononeurosis: Behauioural Approach (Milutinovic, 1990). Grade C Functional Aphonia in Young People (Harris & Richards, 1992).

The complete list of publications will be considered later. Those combining validation of assessment tools and therapy produced one Grade A

study, two at Grade B, and three at Grade C, with the following examples:

Grade A GRBAS Eualuation of Running Speech and Sustained Phonation (Sakata et a1.,1995). Grade B Longtime Auerage Spectograms of Dysphonic Voices (Kitzing & Akerlund, 1993). Grade C Phoniatric Indices of Change (Tosi & Bertaccini, 1990).

In few of these papers was there any description of the therapy type. The paper by Tosi and Bertaccini (1990), Graded C, is an example of an expert opinion giving direc- tion for an index of change which could be widely used. Although it is mentioned in their paper in relation to objective measurement, it could also be applied to subjective ratings and presents a valuable method of showing change.

In the combination of efficacy of surgical intervention and therapy there were no Grade A studies, four at Grade B, and two at Grade C. An example of each grade follows:

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Grade B Ventricular Dysphonia: A Profile of 40 Cases (von Doerston et al., 1992). Grade C The Outcome of Different Management Patterns for Vocal Cord Nodules Lancer et al., 1988).

In the paper by Lancer et al. (1988), the therapy was more fully described than in any of the others.

In all the graded studies, only 17% were Grade A, 50% were Grade B, and 36% were Grade C, demonstrating the need to provide sound evidence of efficacy, espe- cially in therapeutic intervention. It is also interesting to note that as many as 60% of the studies involved validating assessment tools, which may give an indication as to the current state of the art. It appears, therefore, that we are at a point where progress is dependant on developing these tools so that we can adequately measure therapeutic intervention with agreed and standardised procedures.

In his major survey, Hirano (1989) encouraged the development of standardised procedures. From his survey of clinical voice evaluation procedures he identified their type, nature, aim, frequency of use and their reliability in measuring parameters and made suggestions and recommendations for useful measurements.

Hirano (1989) details eight procedures, their purpose, and the parameters to be measured/checked:

1. Perceptual evaluation - pitch, loudness, quality and voice fluctuation. 2. Visual inspection - diagnosis by examination. 3. Tape-recording - documentation and analysis. 4. Stroboscopy - diagnosis of degree and extent of disease and/or disturbance of

5. Measurement of fundamental frequency - degree of dysphonia, potential

6. Measurement of pressure levels - softest and loudest, determining range. 7. Aerodynamic tests - degree of disturbance of aspects of vocal function, moni-

8. Acoustic tests - voice quality, pitch, period perturbation (jitter), amplitude per-

vibration.

of vocal function, monitors change.

tors change, determines glottic competence.

turbation (shimmer) and signal to noise ratio.

Some of these procedures would be readily available in many clinics.

Perceptual evaluation Already the IALP Voice Committee has recommended the use of the GRBAS scale as a standard perceptual evaluation. GRBAS rates on a four-point scale, with G = grade; R = roughness; B = breathiness; A = aesthenicity, and S = strain.

Stroboscopy The Ford and Bless ratings in the chapter ‘Assessment of Laryngeal Function’ found in Assessment and Surgical Management of Voice Disorders (Ford & Bless, 1991) are widely accepted as a standard for stroboscopic evaluation.

Fundamental frequency and sound pressure levels The Voice Range Profile or Phonetogram provides a means of measuring fundamental frequency and sound pressure levels with various studies on standardised procedures, such as those by Schutte and Seidner (1983) and Pederson et a1 (1995).

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Aerodynamic studies There are already recognised and standardised procedures available and in use in many clinics. Kelman et al. (1981)

In many respects, therefore, we have available the tools but perhaps not yet wide enough agreement on how they should be used.Table 1 shows the studies on efficacy of therapy and the grading according to US-AHCPR.

TABLE 1: Studies on efficacy of therapy and their grading according to the US- AHCPR

Study In teruen tion Treatment effect (%) AHCPR Grade

Smith & Thyme (1976)

Specific: Accent method 30 A

C Bridges & Epstein (1983)

No description of therapy 82

Thyme & Frokjaer-Jensen (1987)

Specific: Accent method 100 B

Koufman & Blalock (1 988)

Targeted parametrs and grouped 71 B

B Eclectic 95 Milutinovic (1990)

Carding & Horsely (1992)

Range of techniques: Eclectic 90 A

C Harris & Richards (1992)

Range of techniques: 100 Eclectic

Mueller & Larson (1992) Traditional techniques n/a C

Roy & Leeper (1993)

Specific: Laryngeal massage

Specific: Accent method

8 2 B

Fex & Kotby (1995) no details C

Gordon et al. (1995)

Targeted parameters and grouped 83 B

I3 Schalen et al. (1 995)

No description of therapy 96

In terms of intervention and the efficacy of treatment, it would seem that any study needs to describe the intervention type, whether it is specific in method, for example,

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the Accent method (Smith & Thyme, 1976) or Laryngeal massage (Roy & Leeper, 1993) or Targeting parameters (Kaufman, Blalock & Winston-Salom, 1988; Lockhart, Paton & Pearson, 1995; Gordon et al., in press) or describes therapy techniques as traditional (Mueller & Larson, 1992) or eclectic (Milutinovic, 1990; Carding & Horsely, 1992; Harris & Richards, 1992).

The treatment effect, which would seem to be an obvious inclusion, may not always be so. Whatever approach is used to measure vocal function, it needs to be well- planned, prospective, using reliable measurement, with random control and with trained listeners and random samples.

Having looked, therefore, at the literature review, some recommended procedures in voice evaluation and studies of efficacy of therapy, there is another aspect of efficacy of therapy to be considered. This is the extent to which the disorder effects the quality of communication and quality of life, with a need for an agreed classification of impair- ment which is nationally accepted. This would then allow an assessment of impairment before and after therapy, would assist in determining clinical priorities and has obvious implications on service planning.

In 1980 the World Health Organization published the International Classification of Impairments, Disabilities and Handicaps (WHO, 1980). Impairment is defined as ‘any loss or abnormality of psychological, physiological, or anatomical structure of function’. Vocal cord palsy is an example of this. Disability comprises ‘any restriction or lack (resulting from an impairment) of ability to perform an activity in the manner or within the range considered normal for a human being’. Dysphonia is an example. Handicap is defined as ‘a disadvantage for a given individual, resulting from an impair- ment or disability, that limits or prevents the fulfilment of a role that is normal (depend- ing on age, sex, and social and cultural factors) for that individual’. An example is a teacher with voice impairment.

Valuations on Rosser Health States (Rosser, 1976) describes disability on eight lev- els from ‘no disability’ through ‘unable to continue in employment’, ‘confined to bed’, to ‘unconscious’. This is similarly rated on a four-point scale on the degree of distress involved, from ‘no distress’ to ‘severe, suicidal depression’ or ‘overwhelming anxiety’. Although voice disorders would rarely be described in the Rosser higher levels of dis- ability, they certainly may affect employment and can result in high levels of distress. Enderby (1992) has very nicely married the two approaches together by suggesting that the categories of impairment, disability and handicap be supplemented by a fourth category of ‘distress’ and this format be used with a six-point scale of severity.

For many of us, this involves a new approach to patient treatment: measuring the level of impairment, disability, handicap or distress at the start of therapy; predicting the expected change and measuring that against the final outcome. This can then lead to a second planned episode of care, when the process begins again. Patient/carers and professionals all then reach an agreement score on their impression of the degree of change, involving all concerned.

Even within the limitations of this paper, it is clear that there is a wealth of material on which to build. Our way ahead must involve standards for evaluation of voice, regular monitoring of therapy, evaluation of impairment, disability, handicap and dis- tress, developing ability and skill in predicting change, establishing agreed protocols and care pathways, and auditing our procedures and practices so that we can demon- strate the efficacy of our therapy.

Perhaps our main aim now as clinicians is to assess what is available to us in our clinics, what are our development priorities, and begin to utilise the skills which we

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have in demonstrating efficacy, not necessarily always in research or in studies, but in routine practice, which will be of value both within and outside our profession.

It may seem an awesome task, with some clinicians only too aware of the lack of any objective instrumentation. The encouragement, however, is that no matter what we use, we can ensure and show that it is a standardised and validated tool which can be measured in some form. We can also take heart from Hirano (1989) who says this at the beginning of his major study in this field:

The vocal function is a multidimensional function. It is something like physical strength. Physical strength cannot be determined with any single scale. There is no single measure either with which one can evaluate the entire aspects of the vocal function. Any uocal function test, however useful i t is, can eualuate only part of the vocal function. (p. 89)

So, no matter how good our studies are, they form only a part of the whole picture. As we work together as a profession, planning efficacy studies, using our communica- tion network, sharing our experience and knowledge, we already have at our fingertips the means of demonstrating the efficacy of our therapy in the management of disor- ders of voice.

LITERATURE SEARCH

For a full list of all the literature reviewed, please contact the authors.

REFERENCES

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Koufman JA, Blalock PD, Winston-Salom NC (1988).Vocal fatigue and dysphonia in the professional voice user: Bogart-Bacall syndrome. Laryngoscope 98, 493-498. Lancer JM, Syder D, Jones AS, le Boutillier A (1988). The outcome of different management patterns for vocal cord nodules. Journal of Laryngology and Otology 102, 423-427. Lockhart MS, Paton F, Pearson L (in press) Targets and timescales: a study of dysphonia using objective assessment. Milutinovic 2 (1990). Advantages of indirect video-stroboscopic surgery of the larynx. Folio Phoniatrica 42, 77-82. Mueller PB, Larson GW (1992) Voice therapy practices and techniques: a survey of voice clinicians. Journal of Commununication Disorders 25, 251-260. Pedersen MF, Frokjaer-Jensen B, Pabst F, Schutte HK, Hacki T, Hansen HL (1995). Standardising VRP measurements. IALP Proceedings 23, 41-45. Roy N, Leeper HA (1993). Effects of the manual laryngeal musculoskeletal tension reduction technique as a treatment for functional voice disorders: perceptual and acoustic measures. Journal of Voice 7, 242-249. Sakata T, Kubota N, Yonkawa H, lmaizumi S, Niimi S (1995). GRBAS Evaluation of running speech and sustained phonation. IALP Proceedings 23, 33-36. Sanderson RJ, Maran AGD (1992). The quantitative analysis of dysphonia. Clinical Otolaryngology 17,

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440-443.