Dysarthria: Tools for Clinical Decision-Making Dysarthria represents a group of motor speech disorders characterized by weakness, slowness, and/or lack of coordination of the speech musculature as the result of damage to the central or peripheral nervous system. Diversity is the hallmark of this group of disorders because the dysarthrias vary along a number of dimensions, ... Features
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Features  |   May 01, 2004
Dysarthria: Tools for Clinical Decision-Making
Author Notes
  • Kathryn M. Yorkston, is professor in the department of Rehabilitation Medicine of the University of Washington in Seattle. She chairs the Writing Committee for Practice Guidelines in Dysarthria for the Academy of Neurologic Communication Disorders and Sciences (ANCDS; e-mail: ancds@incnet.com).
    Kathryn M. Yorkston, is professor in the department of Rehabilitation Medicine of the University of Washington in Seattle. She chairs the Writing Committee for Practice Guidelines in Dysarthria for the Academy of Neurologic Communication Disorders and Sciences (ANCDS; e-mail: ancds@incnet.com).×
  • David R. Beukelman, is in the department of Special Education & Communication Disorders at the University of Nebraska in Lincoln, the Division of Speech Language Pathology at the Munroe-Meyer Institute of Genetics and Rehabilitation at the University of Nebraska Medical Center, and Institute for Rehabilitation Science and Engineering at Madonna Rehabilitation Hospital.
    David R. Beukelman, is in the department of Special Education & Communication Disorders at the University of Nebraska in Lincoln, the Division of Speech Language Pathology at the Munroe-Meyer Institute of Genetics and Rehabilitation at the University of Nebraska Medical Center, and Institute for Rehabilitation Science and Engineering at Madonna Rehabilitation Hospital.×
Article Information
Speech, Voice & Prosodic Disorders / Dysarthria / Professional Issues & Training / Features
Features   |   May 01, 2004
Dysarthria: Tools for Clinical Decision-Making
The ASHA Leader, May 2004, Vol. 9, 4-21. doi:10.1044/leader.FTR2.09092004.4
The ASHA Leader, May 2004, Vol. 9, 4-21. doi:10.1044/leader.FTR2.09092004.4
Dysarthria represents a group of motor speech disorders characterized by weakness, slowness, and/or lack of coordination of the speech musculature as the result of damage to the central or peripheral nervous system. Diversity is the hallmark of this group of disorders because the dysarthrias vary along a number of dimensions, including age of onset, natural course, site of lesion, neuropathology, severity, and so on.
Historically, the field of dysarthria has moved through a series of phases. The first phase, which culminated in the mid-1970s with the Mayo Clinic studies, was the era of diagnosis when classic types of dysarthria were distinguished from one another and the speech characteristics associated with neurologic conditions were documented. The second phase was characterized by the development, description, and testing of various types of assessment and intervention procedures. This phase led to an arsenal of potential interventions.
During this phase, it became apparent that intervention for dysarthria was clearly not a “one size fits all” solution. It was also clear that some interventions, although popular and potentially effective for some clients, were not supported empirically or by the authoritative experts for other clients. For example, strengthening exercises may be appropriate for speakers with severe weakness associated with traumatic brain injury but not for those with severe weakness associated with amyotrophic lateral sclerosis. Thus, the field of dysarthria is now entering into a phase of decision-making in which logic must be provided to the clinician for selection and timing of the various interventions.
Clinical decision-making is a process by which facts are gathered, options considered, and a course of action selected. Clinicians working with speakers with dysarthria must make many decisions. For example: What aspects of the disorder will be responsive to treatment? What type of intervention is best? How much intervention is needed? When should the intervention be undertaken? In a lecture to a group of medical educators at the University of Washington, Arthur Elstein (1999) suggested that medical students do the wrong things in a clinical setting not because of a deficiency in knowledge but because they do not make good decisions. They know a lot, but they do not think systematically.
Every profession needs tools. The carpenter needs a hammer, the scholar needs books, and the speech-language pathologist needs tools for systematic decision-making. This article describes two tools that assist clinicians in the decision-making process. The first is a model of disablement that provides a framework for understanding a broad range of consequences of dysarthria and the second is evidence-based practice (EBP) guidelines that provide up-to-date and systematic reviews of intervention-related issues.
Models of Disablement
Before decisions can be made, it is necessary to organize the facts upon which they are made. The World Health Organization model of disablement, now called the International Classification of Function, Disability, and Health (ICF), is a helpful way to organize the consequences of chronic conditions. It is a framework organizing many aspects of disablement including structure and function, activity and participation, and environmental context. The ICF represents a true advancement over earlier models in that it integrates the various dimensions of disablement into a biopsychosocial approach.
Using ICF terminology, the consequences of dysarthria include impairment or changes in structure or function such as respiratory, phonatory, or velopharyngeal dysfunction, limitations in activity such as changes in speech intelligibility or naturalness, and restrictions in participation such as role restrictions in areas such as personal or household management, work, leisure, relationships, and community life. The ICF provides clinicians with a framework by which to evaluate the multiple dimensions of an individual’s speech disability in order to complete a multiple-level assessment, focus the intervention, and evaluate the impact of the intervention.
EBP Guidelines
If models of disablement such as the ICF allow for the identification and organization of the “facts” regarding particular individuals with dysarthria, then the movement toward EBP provides clinicians with a means of using the information at hand to develop a plan of action. EBP is an approach to decision-making in which the clinician uses the best evidence available, in consultation with the patient, to decide upon the option that best suits that patient. Clinical practice guidelines are explicit descriptions of how patients should be evaluated and treated. The purpose of guidelines is to improve the quality of care and to assure it by reducing variation in care. Guidelines develop through systematic review of evidence and, when the evidence is insufficient, through expert opinion.
In 2001 the Academy of Neurologic Communication Disorders and Sciences (ANCDS), with support from ASHA and the Department of Veterans’ Affairs, initiated a project to develop and disseminate EBP guidelines for a range of neurological conditions including dysarthria, aphasia, cognitive-communication disorders associated with traumatic brain injury, dementia, and apraxia of speech (see Frattali et al. [2003] for an overview). The Writing Committee for Practice Guidelines in Dysarthria has published a series of Technical Reports and articles focusing on specific management issues. This series of modules is based on systematic literature searches of both electronic databases (PsychINFO, MEDLINE, and CINAHL) and hand searches of relevant edited books. The topics of the modules were selected because they deal with a clinically relevant problem where approaches to intervention vary and research evidence exists regarding the outcomes of treatment.
Modules
Management of Velopharyngeal Function
The first module focused on management of velopharyngeal function in dysarthria. A total of 33 intervention studies were identified in the categories of prosthetics, surgery, and exercise. Based on evidence in the literature and expert opinion, a flowchart for clinical decision-making was developed. Using this flowchart, clinicians can identify characteristics of speakers with velopharyngeal impairment who are good candidates for interventions such as palatal lifts. For example, the literature suggests that the best candidates for palatal lifts have a flaccid soft palate, pharyngeal wall movement, good oral articulation and respiratory support, and a stable disease course.
Medical Interventions for Spasmodic Dysphonia
In the second module, “Medical Interventions for Spasmodic Dysphonia,” a systematic review of the literature was conducted in which 103 intervention studies were identified in the categories of recurrent laryngeal nerve (RLN) section (20 articles), the use of botulinum toxin (Botox) injections for the management of SD (58 articles), and miscellaneous interventions (25 articles). Because many SLPs work as part of a team that manages individuals with SD, this review provides a historical review of various approaches to medical treatment of this focal dystonia, along with studies of the outcomes of current intervention approaches.
A review of this literature suggests that RLN section as a treatment for adductor SD results in a substantial degree of improvement for a large percentage of patients, but that recurrence of SD signs and symptoms is common. Botox injection also results in a substantial degree of improvement for a large percentage of patients. Benefits generally last for three to four months at which time reinjection is required to maintain the effect. The side effects of a weak or breathy voice and mild dysphagia last for several weeks in many patients. The effectiveness of Botox injection for abductor SD is less pronounced and occurs in a smaller percentage of patients than adductor SD.
Management of Respiratory/Phonatory Dysfunction
The third module developed by the Writing Committee in Dysarthria reviews behavioral techniques for the management of respiratory/ phonatory dysfunction in dysarthria. A search of electronic databases (PsychINFO, MEDLINE, and CINAHL) and hand searches of relevant edited books yielded 35 intervention studies in the categories of biofeedback, device utilization, the Lee Silverman Voice Treatment (LSVT), and several miscellaneous studies.
A review of this literature suggests that biofeedback can be effective in changing physiologic variables, although the relationship between changes in specific physiologic variables and speech production or communication participation has yet to be clearly established. Conclusions about the effectiveness of devices are limited by the small number of subjects studied; however, they may improve the speech loudness and, in most cases, intelligibility of individuals with hypokinetic dysarthria who have not experienced success with behavioral intervention alone. LSVT has been systematically studied in a relatively large number of individuals with Parkinson’s disease. There is strong evidence to suggest immediate post-treatment improvement; there is some evidence of long-term maintenance of effect but the data are complicated by the expected neurologic deterioration in this population and by the small number of studies that report long-term follow up.
Flowcharts for clinical decision-making are provided that assist clinicians in matching client characteristics with possible interventions.
Three general areas of respiratory/phonatory dysfunction are identified to provide an organizing framework for a clinician’s approach to respiratory/ phonatory management. Those areas include: decreased respiratory support, decreased respiratory/phonatory coordination and control, and reduced phonatory function. Within each area, behavioral techniques are delineated in terms of the available support from the dysarthria literature or from expert opinion.
Speech Supplementation
The final module reviews a set of studies where dysarthric speech is supplemented by a variety of cues in order to increase speech intelligibility. Speech supplementation is a group of several different strategies that augment the speaker’s natural speech by providing additional contextual information to convey the spoken message. Speech supplementation techniques offer this additional information, independent of the speech signal, to supplement the highly distorted acoustic signal that is associated with severe dysarthria.
Three general types of speech supplementation are represented in this review: alphabet supplementation, semantic or syntactic supplementation, and illustrative gestures. A total of 19 studies were identified, obtained, and rated. Strategies include alphabet supplementation, in which the speaker indicates the first letter of the word spoken; topic supplementation, in which the speaker indicates the topic of the message, or gestures accompanying and illustrating speech. A review of this literature suggests that speech supplementation strategies may be useful for speakers with severe or profound dysarthria, regardless of medical diagnosis or type of dysarthria. Selection among the various strategies must be made on an individual basis because each strategy has unique advantages and disadvantages. Some strategies may have the benefit of improving speech production, especially in cases where rate reduction is an appropriate target for intervention.
Present and Future
At the beginning of this article, we reviewed some of the many decisions that a speech-language pathologist makes during the course of treating a speaker with dysarthria. Although these decisions are complex, tools are available that assist clinicians in the selection of an appropriate course of intervention. Models of disablement provide a framework for organizing facts about the consequences of the neurologic condition. Evidence-based practice guidelines are thorough, systematic reviews of evidence of opinion. They are explicitly designed to assist in the decision-making process. Our field is undertaking important initial steps in developing practice guidelines that will not only help us make decisions today, but also help us to identify future research needs.
Dysarthria References
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Duffy, J. R. (1995). Motor speech disorders: Substrates, differential diagnosis, and management. St. Louis: Mosby.
Duffy, J. R. (1995). Motor speech disorders: Substrates, differential diagnosis, and management. St. Louis: Mosby.×
Duffy, J. R., & Yorkston, K. M. (2003). Medical interventions for spasmodic dysphonia and some related conditions: A systematic review. Journal of Medical Speech-Language Pathology, 11(4), ix–lviii.
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Elstein, A. (April 27, 1999). Clinical decision-making: Teaching evidence-based practice to medical students. A lecture presented at University of Washington.
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Frattali, C., Bayles, K. A., Beeson, P., Kennedy, M. R. T., Wambaugh, J., & Yorkston, K. M. (2003). Development of evidence-based practice guidelines: Committee update. Journal of Medical Speech-Language Pathology, 11(3), ix–xvii.
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Hanson, E. K., Yorkston, K. M., & Beukelman, D. R. (2004). Speech supplementation techniques for dysarthria: A systematic review. Journal of Medical Speech-Language Pathology, 12(2), ix–xxix.
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Spencer, K. A., Yorkston, K. M., & Duffy, J. R. (2003). Behavioral management of respiratory/phonatory dysfunction from dysarthria: A flowchart for guidance in clinical decision-making. Journal of Medical Speech-Language Pathology, 11(2), xxxix–lxi.
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Yorkston, K. M., Beukelman, D. R., Strand, E. A., & Bell, K. R. (1999). Management of motor speech disorders in children and adults (2nd ed.). Austin, TX: Pro-Ed.
Yorkston, K. M., Beukelman, D. R., Strand, E. A., & Bell, K. R. (1999). Management of motor speech disorders in children and adults (2nd ed.). Austin, TX: Pro-Ed.×
Yorkston, K. M., Spencer, K. A., & Duffy, J. R. (2003). Behavioral management of respiratory/phonatory dysfunction from dysarthria: A systematic review of the evidence. Journal of Medical Speech-Language Pathology, 11(2), xiii–xxxviii.
Yorkston, K. M., Spencer, K. A., & Duffy, J. R. (2003). Behavioral management of respiratory/phonatory dysfunction from dysarthria: A systematic review of the evidence. Journal of Medical Speech-Language Pathology, 11(2), xiii–xxxviii.×
Yorkston, K. M., Spencer, K. A., Duffy, J. R., Beukelman, D. R., Golper, L. A., Miller, R. M., Strand, E. A., & Sullivan, M. (2001). Evidence-Based Practice Guidelines for Dysarthria: Management of Velopharyngeal Function. Journal of Medical Speech-Language Pathology, 9(4), 257–273.
Yorkston, K. M., Spencer, K. A., Duffy, J. R., Beukelman, D. R., Golper, L. A., Miller, R. M., Strand, E. A., & Sullivan, M. (2001). Evidence-Based Practice Guidelines for Dysarthria: Management of Velopharyngeal Function. Journal of Medical Speech-Language Pathology, 9(4), 257–273.×
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May 2004
Volume 9, Issue 9