1 Behav. Thu. & Exp. Psychiar. Vol. 2?, No. 2, pp. 97-101.1991 Pergamon Press plc. Printed m Great Brttain.
0
Cno-7916/91$3.00 1991 Pergamon
+ 0.00 Press plc.
EMG BIOFEEDBACK TREATMENT OF PEDIATRIC HYPERFUNCTIONAL DYSPHONIA KEITH Meyer Rehabilitation
BONNIE
Institute,
D. ALLEN University
BERNSTEIN
of Nebraska
and DAVID
Boys Town National
Research
Medical
Center
H. CHAIT
Hospital
Summary - A 9-year-old boy with a long history of impaired communication resulting from hyperfunctional dysphonia and vocal nodules had proven to be unresponsive to traditional voice therapy. In this study, he engaged in biweekly visual EMG biofeedback training to reduce laryngeal muscle tension. In a multiple baseline design across two responses with changing criteria, results demonstrated sequential stepwise reductions in muscle tension with each new criterion. Concomitant improvements were found in laryngeal aerodynamic functioning and in voice quality. The treatment also resulted in the elimination of the vocal nodules without surgical intervention. These effects were maintained at 6 month follow-up.
Functional voice disorders are frequently characterized by excessive muscular contraction within the vocal tract (Boone, 1983). Hyperfunctional dysphonia (HFD), a type of functional voice disorder, involves difficulty in voice production that cannot be explained by any structural or neurological lesion (House & Andrews, 1988). It is attributed to excessive activity in the lateral cricoarytenoid muscle, resulting in over-adduction of the vocal cords. External features include visible and palpable muscular tension around the larynx (Morrison, Nichol, & Rammage, 1986). When prolonged, this condition may result in vocal nodules, partial loss of phonatory ability, vocal fatigue and throat pain (Redenbaugh & Reich, 1989). Approximately 69% of all children have voice problems with the most frequent complaints being dysphonia, with vocal fatigue and hoarseness (Wilson, 1979). Effective treatment is critical since dysphonia can greatly restrict communicative effectiveness (Reed. 1980). Traditional voice therapy has typically focused on developing the ability to reduce tension in All correspondence should bc addressed Omaha. NE 6X198-5350. U.S.A.
to: Keith
the laryngeal area through muscle relaxation exercises (e.g., Greene, 1980). Children with dysphonia do not, however, reliably respond to traditional voice therapy (Wilson, 1979; Moran & Pentz, 1987), creating a need for alternative means of treatment for children with HFD (Reed, 1980). Electromyographic (EMG) biofeedback is one such promising alternative. EMG biofeedback facilitates selective control of specific muscle activity. Successful rehabilitation and treatment has been demonstrated with EMG biofeedback in a variety of neuromuscular and localized muscular disorders in adults (e.g., Haynes, 1976; Brudny, Grynbaum, & Korein, 1974), and in children (e.g., Wooldridge & Russell, 1976; Basmajian, Takebe, Kukula, & Narayan, 1976). The extension of EMG biofeedback to children experiencing hyperfunctional dysphonia, however, has not been demonstrated. In fact, while several studies with adults have shown promising results, these investigations have failed to demonstrate the experimental control necessary to evaluate
D. Allen.
97
MRI.
Department
of Psychology,
600 S. 42nd Street.
9x
KEITH
D. ALLEN,
BONNIE
BERNSIEIN
critically the efficacy of the procedures (Prosek. Montgomery, Walden, & Schwartz, 1978; Stemple. Weiler, Whitehead, & Komray, 1080; Andrews, Stewart. & Warner 1986). A well-controlled empirical investigation of the efficacy of EMG biofeedback in the treatment of HFD remains to be done. The purpose of this research was to provide a controlled investigation of the efficacy of EMG biofeedback in the reduction of laryngeal muscle tension in a child with hyperfuntional dysphonia. In addition, the study evaluates EMG biofeedback as a nonsurgical alternative to the treatment of vocal nodules through the reduction of excessive laryngeal muscle tension.
Method Subject The subject was a Y-year-old white male with a 5 year history of hyperfunctional dysphonia. He was referred from Boys Town National Research Hospital where he had been diagnosed with HFD at the age of 4 and had a 3 year history of unresponsiveness to traditional voice therapy (i.e.. vocal abuse prevention. relaxation training, vocal rehabilitation). Vocal nodules had developed, further impairing vocal production. and surgery had been recommended to remove the nodules. Intervention to reduce muscle tension was requested so that following surgery, the nodules would not return. Initial screening involved a standardized voice and medical evaluation to rule out organic pathology.
~lcc,tr-onlyoRr(~I’Ilic.mwurc. EMG activity monitored and recorded via a computed-ized Bio-Track (Expanded Technologies, Inc.) biofeedback system. EMG signals were amplified and filtered using a .I & .I Clinical Scric$ M57 monitor. The r:lw EMG 4gnal was was
and DAVID
H. CHAI-I
band-pass filtered (25-1000 Hz) and averaged using a 2 set integration period. EMG electrodes were placed ipsilaterally and vertically, in parallel alignment, over the thyrohyoid membrane with a ground electrode placed on the wrist. Laryngeul uerodynumic msessment. Estimated subglottic pressure (from oral air pressure) was measured to provide quantitative information about laryngeal constriction at the level of the glottis during speech tasks. Measures were obtained from a pneumotachograph with a face mask attached to a pressure transducer and then amplified for analysis. Perceptual meusrire. Voice quality was evaluated by speech pathologists and the subject’s parents using the Buffalo II Voice Profile (Boone, lY83). Ratings on the profile are made using a 5 point Likert scale, with an overall rating reflecting the degree of deviation in speech production factors such as tone, pitch, loudness, tension, and intelligibility. Video endoscopic cvuluutiorz. Direct visual examination of the vocal cords was performed by an otolaryngologist using a fiberoptic endoscope to evaluate the integrity and action of vocal cords and surrounding muscles during speech.
EMG biofeedback training was introduced a multiple baseline design across two rcS~OIIS~S (resting or nonspeaking EMG and speaking EMG) with changing criteria. The two responses wcrc measured over time to provide baselines against which changes could be evaluated. Treatment was introduced after varying amounts of time in baseline. Treatment was carried out until ;I preset criterion was met, then a more stringent criterion w;15 experimental control i\ set. In thi\ design, demonstrated through the replication of trcatment cffccts with each behavior ~equentiall!~. in
EMG Biofeedback
and through the replication of stepwise reductions in muscle tension with increasingly difficult criteria. Procedure During baseline, following a 10 min habituation period, EMG measures of laryngeal muscle tension and voice quality during both phases were recorded and parental ratings of voice quality were obtained. During treatment, Tim was seen on a biweekly basis for a 30 min visual biofeedback training session. Following a shorter, 5 min habituation period, Tim was presented with 20 consecutive, 30 set trials, first during the resting or nonspeaking phase, then during a speaking phase. The two biofeedback phases were separated by a 5 min “no practice” period. During the biofeedback, Tim was instructed to attempt to reduce muscle tension around the vocal cords by observing feedback about laryngeal muscle tension. A microvolt criterion was established based on individual baseline data. During the resting and speaking phases, the criterion was lowered 0.5 uV and 5 yV, respectively each time the established criterion was met during at least 80% of the trials for three consecutive sessions. Two additional voice evaluations (voice recordings and pressure assessments) were performed as treatment progressed. Termination criterion was based on norm-referenced baseline data collected from adults since no normative data is available from children. Once termination criterion had been met, posttreatment EMG and voice evaluations were conducted. Follow-up assessments were performed at 3 and 6 months.
Treatment
99
tension across both types of responses. As Figure 1 shows, resting levels of EMG were reduced from an average of 7.5 uV in baseline to 3.2 uV at the conclusion of treatment. EMG activity during the speaking condition averaged 49.5 uV during baseline measurements. At the conclusion of treatment, these levels had been reduced to 10 uV posttreatment. These low levels of muscle tension were found to be maintained at 3 and 6 month follow-up examinations. Commensurate with decreases in laryngeal muscle tension were large reductions in subglottal pressure. Figure 2 shows that subglottic pressures in baseline were significantly higher than normal levels of subglottal pressure for children (i.e., greater than 3 SD). Following the introduction of treatment, subglottic pressure was reduced to levels equal to or below the established norms for this age group (Netsell, Lotz, & Barlow, 1989). Bosellne 65 60 F 75
I
Treatment
I Resting
7.0
phase
65 g
60
2 k 5
5.5 5.0 45 40 35 30 25 3mo 6mo follow-up
Treatment
Speaking
phase
-
Results The results baseline EMG introduction of results indicate reductions in
indicate stable or increasing activity levels. Following the EMG biofeedback training, the the replication of stepwise the average level of muscle
Figure 1. Average microvolts/session for last three sessions at each criterion. Criteria are indicated by solid horizontal lines.
KEITH
100
D. ALLEN.
BONNIE
m
Baseline
@B
Treatment
---
3SD
-
Age group mean (SD=1 6)
BERNSTEIN
and DAVID
H. CIIAIT
of the posterior of the true vocal folds, protruding well beyond the free edge of the vocal fold. The nodules were noted to decrease in size throughout treatment and at 3 month follow-up were noted. according to the otolaryngologist’s report, to be “dramaticaly rcduced.” At 6 month follow-up evaluation, the nodules were reported to be gone. Subsequently, plans for surgical removal of the nodules were canceled.
Discussion
Voice recordings taken before, during and following treatment were randomly presented to five speech therapists for blind ratings of voice quality. Figure 3 shows the ratings of the therapists, who rated Tim’s voice quality as severely impaired in baseline and near normal at post-treatment and at 6 month follow-up. Ratings of voice quality were also provided by the parents who rated Tim ;I 4 in baseline and a 2 at post-treatment and 6 month follow-up. Finally, video endoscopic evaluations were performed in baseline. during treatment, and at 3 and 6 month follow-up evaluations. Initially, there were large prominent nodules which occupied 33% of the anterior and 66%
5-
This study has demonstrated that EMG biofeedback can be an effective alternative to conventional voice therapy in the treatment of hyperfunctional dysphonia. The acquisition of behavioral control of specific muscle sites through criterion-based EMG biofeedback by a child was found to reduce significantly laryngeal muscle tension resulting in improved laryngeal aerodynamic functioning. More importantly, the treatment resulted in the elimination of chronic vocal nodules without surgical intervention. In addition, these effects were then maintained at 6 month follow-up in a child who had previously proven unresponsive to conventional voice therapy. This investigation also provides a demonstration of the social validity of the treatment effects. Social validation involves an attempt to quantify whether meaningful change has been achieved with treatment (Kazdin, 1977). This requires comparing an individual’s results with others (i.c., normative data) and/or a subjective evaluation of the results by those in a special position (i.c.. through expertise) to judge the behavior. Subglottal pressure was found to be comparable to normative age group values, while voice quality was found to be markedly improved when independently evaluated by voice experts. In addition, parental report of voice quality improvement suggests that there was generalization of effects to the home and other nonclinic settings. These results support the clinical or applied signifi-
EMG
101
Biofeedh ack Treatment
cance of EMG biofeedback as an alternative treatment for HFD. The demonstration of the effectiveness of this procedure has significant treatment implications for a number of additional functional voice disorders. Paradoxic vocal cord motion occurs when laryngeal constriction on inspiration results in asthma-like responses, and possibly hoarseness and vocal ulcers (Martin, Blager, Gay, & Wood, 1987). The condition has been conceptualized as a conversion or somatization disorder, with conventional treattherapy and ment centered on voice psychotherapy. EMG biofeedback has not been explored as a treatment alternative, although the recognized goal of treatment is the reduction of tension in the extrinsic laryngeal musculature (Martin et al., 1987). Similarly, ventricular fold phonation is a musculoskeletal tension disorder in which the ventricular folds adduct over the true vocal cords, resulting in a hoarse, gravel-sounding voice (Aronson, 1980). The objective measurement and controlled evaluation of existing and alternative treatments such as EMG biofeedback is important to the successful treatment and management of these and other functional voice disorders. Future research may also focus on the development of a more “streamlined,” treatment protocol. For example, home-based programs require fewer office visits and place greater emphasis on practice at home rather than in the clinic. Additional research will also need to explore whether treatment effects can be more quickly generalized by targeting speaking rather than resting responses first. Efforts to streamline and refine EMG biofeedback will ultimately provide an intervention that is less costly and more widely available to children with functional voice disorders.
References Andrews. S., Stewart, R.. & Warner. J. (19X6). EMG biofeedback and relaxation in the treatment of hyper-
functional
dysphonia.
Brilish Journul of Disorders in 21, 353-367. Aronson, A. ( 1980). Clinical voice disorders: an interdisciplinary approach. New York: Brain C. Decker. Communication.
Basmajian, J. V., Takebe. K., Kukula, C. G., & Narayan, M. G. (1976). Biofeedback treatment of foot drop after stroke compared with standard rehabilitation technique. Archives of‘ Physical Medicine and Rehabililalion. 57. Y11. Boone, D. R. (1983). The voice and voice lherapy (3rd cd) New Jersey, Prentice Hall. Brudny. J.. Grynbaum. B. B.. Ct Korcin, J. (1974). Spasmodic torticollis: Treatment by feedback display of the EMG. Archives Physical Medicul Rehabilirarion, 5.5, 403-408.
Greene,
M. C. L. (1980). The voice and its disorders. York: Pitman Medical. Haynes, S. N. (1976). Electromyographic biofeedback treatment of a woman with chronic dysphagia. EiofeedNew
back
Self-Regulation.
I,
121-126.
House. A. 0.. & Andrcws, H. B. (1988). Life events and difficulties preceding the onset of functional dysphonia. Journal of Psychosomalic Research, 32, 31 l-319. Kazdin, A. E. (1977). Assessing the clinical or applied importance of behavior change through social validation. Behavior Modificution. I, 427-45 1. Moran. M. J.. & Pentz. A. L. (lYX7). Otolaryngologists’ opinions of voice therapy for vocal nodules in children. Lunguage, 172-178.
Speech.
and Hearing
Services irr Schools.
19.
Morrison, M. D.. Nichol. H.. 6i Rammage, L. A. (19X6). Diagnostic criteria in functional dysphonia. l*uryngoscope, 94, l-8. Martin, R. J., Blager. F. B., Gay. M. L., & Wood. R. P. (1987). Paradoxic vocal cord motion in presumed asthmatics. Senlinars in Respirarory Medicine, 8, 332337.
Netsell, R., Lotz. W. K., & Barlow, S. M. (lY8Y). A speech physiology examination for individuals with dysarthria. In K. M. Yorkston & D. R. Beukclman (Eds.). Recent advances in clinical dysarrhrta, Boston: College-Hill Press. Prosek, R. A.. Montgomery. A. A., Walden, B. E., & Schwartz. D. M. (1078). EMG Biofeedback in the treatment of hypcrfunctional voice disorders. Journal oj Speech
and
Hearing
Disorder,~.
43. 282-294.
Redenbaugh, M. A.. & Reich, A. R. (1089). Surface EMG and related measures in normal and vocally hyperfunctional speakers. Journal of Speech and Hraring
Recd.
Disorders.
54,
h&73.
C. G. (lYH0). Voice therapy:
Journal
of Speech and Hearing
A need for research. Disorders,
4.5, 157-169.
Stemple, J. C.. Weiler. E.. Whitehead, W., bi Komray, R. (lY80). Electromyographic biofcedhack training with patients exhibiting a hyperfunctional voice disorder. Laryqoscope. 90, 47 l-476. Wilson, K. D. (197’)) Voice problems of‘ children, Baltimore. Williams & Wilkins. Wooldridge. C. P., 62 Russell, G. (1976). Head position training with the cerebral palsied child: An application of biofeedback techniques. Archives of‘ Physu-a/ Medicine and
RehubiliruGon.
57,
407-414.
0
Cno-7916/91$3.00 1991 Pergamon
+ 0.00 Press plc.
EMG BIOFEEDBACK TREATMENT OF PEDIATRIC HYPERFUNCTIONAL DYSPHONIA KEITH Meyer Rehabilitation
BONNIE
Institute,
D. ALLEN University
BERNSTEIN
of Nebraska
and DAVID
Boys Town National
Research
Medical
Center
H. CHAIT
Hospital
Summary - A 9-year-old boy with a long history of impaired communication resulting from hyperfunctional dysphonia and vocal nodules had proven to be unresponsive to traditional voice therapy. In this study, he engaged in biweekly visual EMG biofeedback training to reduce laryngeal muscle tension. In a multiple baseline design across two responses with changing criteria, results demonstrated sequential stepwise reductions in muscle tension with each new criterion. Concomitant improvements were found in laryngeal aerodynamic functioning and in voice quality. The treatment also resulted in the elimination of the vocal nodules without surgical intervention. These effects were maintained at 6 month follow-up.
Functional voice disorders are frequently characterized by excessive muscular contraction within the vocal tract (Boone, 1983). Hyperfunctional dysphonia (HFD), a type of functional voice disorder, involves difficulty in voice production that cannot be explained by any structural or neurological lesion (House & Andrews, 1988). It is attributed to excessive activity in the lateral cricoarytenoid muscle, resulting in over-adduction of the vocal cords. External features include visible and palpable muscular tension around the larynx (Morrison, Nichol, & Rammage, 1986). When prolonged, this condition may result in vocal nodules, partial loss of phonatory ability, vocal fatigue and throat pain (Redenbaugh & Reich, 1989). Approximately 69% of all children have voice problems with the most frequent complaints being dysphonia, with vocal fatigue and hoarseness (Wilson, 1979). Effective treatment is critical since dysphonia can greatly restrict communicative effectiveness (Reed. 1980). Traditional voice therapy has typically focused on developing the ability to reduce tension in All correspondence should bc addressed Omaha. NE 6X198-5350. U.S.A.
to: Keith
the laryngeal area through muscle relaxation exercises (e.g., Greene, 1980). Children with dysphonia do not, however, reliably respond to traditional voice therapy (Wilson, 1979; Moran & Pentz, 1987), creating a need for alternative means of treatment for children with HFD (Reed, 1980). Electromyographic (EMG) biofeedback is one such promising alternative. EMG biofeedback facilitates selective control of specific muscle activity. Successful rehabilitation and treatment has been demonstrated with EMG biofeedback in a variety of neuromuscular and localized muscular disorders in adults (e.g., Haynes, 1976; Brudny, Grynbaum, & Korein, 1974), and in children (e.g., Wooldridge & Russell, 1976; Basmajian, Takebe, Kukula, & Narayan, 1976). The extension of EMG biofeedback to children experiencing hyperfunctional dysphonia, however, has not been demonstrated. In fact, while several studies with adults have shown promising results, these investigations have failed to demonstrate the experimental control necessary to evaluate
D. Allen.
97
MRI.
Department
of Psychology,
600 S. 42nd Street.
9x
KEITH
D. ALLEN,
BONNIE
BERNSIEIN
critically the efficacy of the procedures (Prosek. Montgomery, Walden, & Schwartz, 1978; Stemple. Weiler, Whitehead, & Komray, 1080; Andrews, Stewart. & Warner 1986). A well-controlled empirical investigation of the efficacy of EMG biofeedback in the treatment of HFD remains to be done. The purpose of this research was to provide a controlled investigation of the efficacy of EMG biofeedback in the reduction of laryngeal muscle tension in a child with hyperfuntional dysphonia. In addition, the study evaluates EMG biofeedback as a nonsurgical alternative to the treatment of vocal nodules through the reduction of excessive laryngeal muscle tension.
Method Subject The subject was a Y-year-old white male with a 5 year history of hyperfunctional dysphonia. He was referred from Boys Town National Research Hospital where he had been diagnosed with HFD at the age of 4 and had a 3 year history of unresponsiveness to traditional voice therapy (i.e.. vocal abuse prevention. relaxation training, vocal rehabilitation). Vocal nodules had developed, further impairing vocal production. and surgery had been recommended to remove the nodules. Intervention to reduce muscle tension was requested so that following surgery, the nodules would not return. Initial screening involved a standardized voice and medical evaluation to rule out organic pathology.
~lcc,tr-onlyoRr(~I’Ilic.mwurc. EMG activity monitored and recorded via a computed-ized Bio-Track (Expanded Technologies, Inc.) biofeedback system. EMG signals were amplified and filtered using a .I & .I Clinical Scric$ M57 monitor. The r:lw EMG 4gnal was was
and DAVID
H. CHAI-I
band-pass filtered (25-1000 Hz) and averaged using a 2 set integration period. EMG electrodes were placed ipsilaterally and vertically, in parallel alignment, over the thyrohyoid membrane with a ground electrode placed on the wrist. Laryngeul uerodynumic msessment. Estimated subglottic pressure (from oral air pressure) was measured to provide quantitative information about laryngeal constriction at the level of the glottis during speech tasks. Measures were obtained from a pneumotachograph with a face mask attached to a pressure transducer and then amplified for analysis. Perceptual meusrire. Voice quality was evaluated by speech pathologists and the subject’s parents using the Buffalo II Voice Profile (Boone, lY83). Ratings on the profile are made using a 5 point Likert scale, with an overall rating reflecting the degree of deviation in speech production factors such as tone, pitch, loudness, tension, and intelligibility. Video endoscopic cvuluutiorz. Direct visual examination of the vocal cords was performed by an otolaryngologist using a fiberoptic endoscope to evaluate the integrity and action of vocal cords and surrounding muscles during speech.
EMG biofeedback training was introduced a multiple baseline design across two rcS~OIIS~S (resting or nonspeaking EMG and speaking EMG) with changing criteria. The two responses wcrc measured over time to provide baselines against which changes could be evaluated. Treatment was introduced after varying amounts of time in baseline. Treatment was carried out until ;I preset criterion was met, then a more stringent criterion w;15 experimental control i\ set. In thi\ design, demonstrated through the replication of trcatment cffccts with each behavior ~equentiall!~. in
EMG Biofeedback
and through the replication of stepwise reductions in muscle tension with increasingly difficult criteria. Procedure During baseline, following a 10 min habituation period, EMG measures of laryngeal muscle tension and voice quality during both phases were recorded and parental ratings of voice quality were obtained. During treatment, Tim was seen on a biweekly basis for a 30 min visual biofeedback training session. Following a shorter, 5 min habituation period, Tim was presented with 20 consecutive, 30 set trials, first during the resting or nonspeaking phase, then during a speaking phase. The two biofeedback phases were separated by a 5 min “no practice” period. During the biofeedback, Tim was instructed to attempt to reduce muscle tension around the vocal cords by observing feedback about laryngeal muscle tension. A microvolt criterion was established based on individual baseline data. During the resting and speaking phases, the criterion was lowered 0.5 uV and 5 yV, respectively each time the established criterion was met during at least 80% of the trials for three consecutive sessions. Two additional voice evaluations (voice recordings and pressure assessments) were performed as treatment progressed. Termination criterion was based on norm-referenced baseline data collected from adults since no normative data is available from children. Once termination criterion had been met, posttreatment EMG and voice evaluations were conducted. Follow-up assessments were performed at 3 and 6 months.
Treatment
99
tension across both types of responses. As Figure 1 shows, resting levels of EMG were reduced from an average of 7.5 uV in baseline to 3.2 uV at the conclusion of treatment. EMG activity during the speaking condition averaged 49.5 uV during baseline measurements. At the conclusion of treatment, these levels had been reduced to 10 uV posttreatment. These low levels of muscle tension were found to be maintained at 3 and 6 month follow-up examinations. Commensurate with decreases in laryngeal muscle tension were large reductions in subglottal pressure. Figure 2 shows that subglottic pressures in baseline were significantly higher than normal levels of subglottal pressure for children (i.e., greater than 3 SD). Following the introduction of treatment, subglottic pressure was reduced to levels equal to or below the established norms for this age group (Netsell, Lotz, & Barlow, 1989). Bosellne 65 60 F 75
I
Treatment
I Resting
7.0
phase
65 g
60
2 k 5
5.5 5.0 45 40 35 30 25 3mo 6mo follow-up
Treatment
Speaking
phase
-
Results The results baseline EMG introduction of results indicate reductions in
indicate stable or increasing activity levels. Following the EMG biofeedback training, the the replication of stepwise the average level of muscle
Figure 1. Average microvolts/session for last three sessions at each criterion. Criteria are indicated by solid horizontal lines.
KEITH
100
D. ALLEN.
BONNIE
m
Baseline
@B
Treatment
---
3SD
-
Age group mean (SD=1 6)
BERNSTEIN
and DAVID
H. CIIAIT
of the posterior of the true vocal folds, protruding well beyond the free edge of the vocal fold. The nodules were noted to decrease in size throughout treatment and at 3 month follow-up were noted. according to the otolaryngologist’s report, to be “dramaticaly rcduced.” At 6 month follow-up evaluation, the nodules were reported to be gone. Subsequently, plans for surgical removal of the nodules were canceled.
Discussion
Voice recordings taken before, during and following treatment were randomly presented to five speech therapists for blind ratings of voice quality. Figure 3 shows the ratings of the therapists, who rated Tim’s voice quality as severely impaired in baseline and near normal at post-treatment and at 6 month follow-up. Ratings of voice quality were also provided by the parents who rated Tim ;I 4 in baseline and a 2 at post-treatment and 6 month follow-up. Finally, video endoscopic evaluations were performed in baseline. during treatment, and at 3 and 6 month follow-up evaluations. Initially, there were large prominent nodules which occupied 33% of the anterior and 66%
5-
This study has demonstrated that EMG biofeedback can be an effective alternative to conventional voice therapy in the treatment of hyperfunctional dysphonia. The acquisition of behavioral control of specific muscle sites through criterion-based EMG biofeedback by a child was found to reduce significantly laryngeal muscle tension resulting in improved laryngeal aerodynamic functioning. More importantly, the treatment resulted in the elimination of chronic vocal nodules without surgical intervention. In addition, these effects were then maintained at 6 month follow-up in a child who had previously proven unresponsive to conventional voice therapy. This investigation also provides a demonstration of the social validity of the treatment effects. Social validation involves an attempt to quantify whether meaningful change has been achieved with treatment (Kazdin, 1977). This requires comparing an individual’s results with others (i.c., normative data) and/or a subjective evaluation of the results by those in a special position (i.c.. through expertise) to judge the behavior. Subglottal pressure was found to be comparable to normative age group values, while voice quality was found to be markedly improved when independently evaluated by voice experts. In addition, parental report of voice quality improvement suggests that there was generalization of effects to the home and other nonclinic settings. These results support the clinical or applied signifi-
EMG
101
Biofeedh ack Treatment
cance of EMG biofeedback as an alternative treatment for HFD. The demonstration of the effectiveness of this procedure has significant treatment implications for a number of additional functional voice disorders. Paradoxic vocal cord motion occurs when laryngeal constriction on inspiration results in asthma-like responses, and possibly hoarseness and vocal ulcers (Martin, Blager, Gay, & Wood, 1987). The condition has been conceptualized as a conversion or somatization disorder, with conventional treattherapy and ment centered on voice psychotherapy. EMG biofeedback has not been explored as a treatment alternative, although the recognized goal of treatment is the reduction of tension in the extrinsic laryngeal musculature (Martin et al., 1987). Similarly, ventricular fold phonation is a musculoskeletal tension disorder in which the ventricular folds adduct over the true vocal cords, resulting in a hoarse, gravel-sounding voice (Aronson, 1980). The objective measurement and controlled evaluation of existing and alternative treatments such as EMG biofeedback is important to the successful treatment and management of these and other functional voice disorders. Future research may also focus on the development of a more “streamlined,” treatment protocol. For example, home-based programs require fewer office visits and place greater emphasis on practice at home rather than in the clinic. Additional research will also need to explore whether treatment effects can be more quickly generalized by targeting speaking rather than resting responses first. Efforts to streamline and refine EMG biofeedback will ultimately provide an intervention that is less costly and more widely available to children with functional voice disorders.
References Andrews. S., Stewart, R.. & Warner. J. (19X6). EMG biofeedback and relaxation in the treatment of hyper-
functional
dysphonia.
Brilish Journul of Disorders in 21, 353-367. Aronson, A. ( 1980). Clinical voice disorders: an interdisciplinary approach. New York: Brain C. Decker. Communication.
Basmajian, J. V., Takebe. K., Kukula, C. G., & Narayan, M. G. (1976). Biofeedback treatment of foot drop after stroke compared with standard rehabilitation technique. Archives of‘ Physical Medicine and Rehabililalion. 57. Y11. Boone, D. R. (1983). The voice and voice lherapy (3rd cd) New Jersey, Prentice Hall. Brudny. J.. Grynbaum. B. B.. Ct Korcin, J. (1974). Spasmodic torticollis: Treatment by feedback display of the EMG. Archives Physical Medicul Rehabilirarion, 5.5, 403-408.
Greene,
M. C. L. (1980). The voice and its disorders. York: Pitman Medical. Haynes, S. N. (1976). Electromyographic biofeedback treatment of a woman with chronic dysphagia. EiofeedNew
back
Self-Regulation.
I,
121-126.
House. A. 0.. & Andrcws, H. B. (1988). Life events and difficulties preceding the onset of functional dysphonia. Journal of Psychosomalic Research, 32, 31 l-319. Kazdin, A. E. (1977). Assessing the clinical or applied importance of behavior change through social validation. Behavior Modificution. I, 427-45 1. Moran. M. J.. & Pentz. A. L. (lYX7). Otolaryngologists’ opinions of voice therapy for vocal nodules in children. Lunguage, 172-178.
Speech.
and Hearing
Services irr Schools.
19.
Morrison, M. D.. Nichol. H.. 6i Rammage, L. A. (19X6). Diagnostic criteria in functional dysphonia. l*uryngoscope, 94, l-8. Martin, R. J., Blager. F. B., Gay. M. L., & Wood. R. P. (1987). Paradoxic vocal cord motion in presumed asthmatics. Senlinars in Respirarory Medicine, 8, 332337.
Netsell, R., Lotz. W. K., & Barlow, S. M. (lY8Y). A speech physiology examination for individuals with dysarthria. In K. M. Yorkston & D. R. Beukclman (Eds.). Recent advances in clinical dysarrhrta, Boston: College-Hill Press. Prosek, R. A.. Montgomery. A. A., Walden, B. E., & Schwartz. D. M. (1078). EMG Biofeedback in the treatment of hypcrfunctional voice disorders. Journal oj Speech
and
Hearing
Disorder,~.
43. 282-294.
Redenbaugh, M. A.. & Reich, A. R. (1089). Surface EMG and related measures in normal and vocally hyperfunctional speakers. Journal of Speech and Hraring
Recd.
Disorders.
54,
h&73.
C. G. (lYH0). Voice therapy:
Journal
of Speech and Hearing
A need for research. Disorders,
4.5, 157-169.
Stemple, J. C.. Weiler. E.. Whitehead, W., bi Komray, R. (lY80). Electromyographic biofcedhack training with patients exhibiting a hyperfunctional voice disorder. Laryqoscope. 90, 47 l-476. Wilson, K. D. (197’)) Voice problems of‘ children, Baltimore. Williams & Wilkins. Wooldridge. C. P., 62 Russell, G. (1976). Head position training with the cerebral palsied child: An application of biofeedback techniques. Archives of‘ Physu-a/ Medicine and
RehubiliruGon.
57,
407-414.
