A Behavioral Therapy Approach for Dysarthria

Introduction

Dysarthria is a group of motor disorders that result from congenital conditions or neurological injury, disease, or disorder.  “[It] is characterized by abnormalities in the strength, speed, range, steadiness, tone, or accuracy of movements required for breathing, phonatory, resonatory, articulatory, or prosodic aspects of speech production” (Duffy, 2013).  Furthermore, these abnormalities are related to sensorimotor problems such as weakness or paralysis, incoordination, involuntary movements, or excessive, reduced, or variable muscle tone (Duffy, 2013).  There are different types of dysarthrias that present with an array of symptoms depending on where the damage or lesion is located.  These include flaccid, spastic, ataxic, hyperkinetic, hypokinetic, and mixed.  The treatment procedures for dysarthria have an emphasis on the oral speech mechanism and focus on enhancing phonation, articulation, prosody, resonance, and respiration. Although there are many treatments for dysarthria, for the purpose of this research paper, the treatment of interest will be hand/finger tapping.  Hand/finger tapping is a behavioral approach for increasing speech intelligibility and lessening the perception of hypernasality (Freed, 2020).

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Finger or hand tapping is a behavioral approach that attempts to control the rate and rhythm of speech (Freed, 2020).  According to the American Speech-Language-Hearing Association (ASHA), rate and rhythm control approaches like hand/finger tapping use intonation patterns (i.e., melody, rhythm, and stress) to improve speech production.  Although, these approaches are aimed at improving prosody they have also been shown to improve articulation as well (ASHA, n.d.).  The target population for the utilization of hand/finger tapping are individuals presenting with flaccid dysarthria, hypokinetic dysarthria, ataxic dysarthria, spastic dysarthria, and apraxia of speech.

Methodology

 Data was obtained using the following database search engines: American Speech-Language-Hearing Association (ASHA), EBSCOhost Cumulative Index to Nursing and Allied Health Literature (CINAHL), National Center for Biotechnology Information (NCBI) PubMed, and PsychINFO.  All articles included are peer-reviewed and relate to pacing strategies such as hand/finger tapping, rhythmic cueing, and melodic intonation therapy in the treatment of motor speech disorders. Data focuses on the adult population whom have been medically diagnosed with motor speech disorders.  Terms searched included the following: dysarthria, pacing strategies, hand/finger tapping, apraxia of speech, metrical pacing, metronome, reduced rate, and motor speech disorders, intelligibility, and rhythmic cueing.

Literature Review

Hand Gesturing as a Potential Compensatory Communicative Strategy in Dysarthria

People naturally partake in hand gesturing while speaking.  It provides different communicative functions and is part of the typical speaker-listener interaction.  In their study, Garcia, Cannito, and Dagenais (2015), strived to examine the nature of hand gestures as a compensatory communicative strategy in dysarthria treatment.  There are various subtypes of gesticulations, which is described as a rhythmic movement that highlights or accentuates speech.  Furthermore, “it is short and quick, typically a flick of the hand or fingers up and down or back and forth that involves rhythmic movements that depict the rhythm or pacing or an event (as cited in McNeill, 1992, p. 108; Ekman & Friesen 1969, 1972, p. 108).”

When investigating the effect of gesticulation on speech intelligibility, Garcia et al. (2015) state that beats served as an external rhythmic marker or cue around which prosodic phrases may be reorganized.  In addition, speaking on a rhythmic beat has been shown to result in more precise articulation and can lead to an improvement in speech intelligibility for some individuals with dysarthria (as cited in Rosenbek, 1984; Yorkston & Beukelman, 1981; Yorkston et al., 1999).  When utilizing gesticulations as a possible treatment approach, it is important to take into consideration individuals with dysarthria that have significantly impaired neuromuscular control.  Reduced motor capabilities may affect the ability to use gesticulations efficiently enough to benefit from this treatment approach.  For example, individuals with Parkinson’s disease and hypokinetic dysarthria have reduced movement and may not benefit from this type of treatment (Garcia et al., 2015).

Overall, the researchers found that gesticulation can have a negative and positive influence of communication.  In addition, they considered beat gesticulation to be a more effective approach for mildly impaired speakers when their goal was to improve speech naturalness and more precise articulation.  Garcia et al., also recognized research limitations such as their research study being focused on scripted gesticulations to quantify their contribution to dysarthric speech in specific situations (2015).  For future research, they suggested a single subject or group design to better understand the effects of gesticulations using controlled treatment protocols.

Implementation of Rhythm to Decrease the Rate of Speech

 Since hand/finger tapping utilizes melody, rhythm, and stress, it makes sense that it can be used in conjunction with music therapy.  As a result, music therapy has been used in neuropsychological rehabilitation.  Music therapists have worked alongside healthcare professionals in aiding the rehabilitation of clients with brain trauma injuries (Cohen, 1988).  The purpose of Cohen’s study was to investigate whether the implementation of superimposed rhythm with a right brain injured adolescent would produce a slower rate of speech. 

The subject was an 18-year-old adolescent female with Kluver-Bucy syndrome.  According to the National Institute of Neurological Disorders and Stroke (NIH), Kluver-Bucy syndrome is a rare behavioral impairment that results from damage to the anterior temporal lobes of the brain (NIH, 2018).  It presents with hyperorality (insertion of inappropriate objects in the mouth), inappropriate sexual behavior, and compulsive eating.  This particular subject demonstrated hyperorality, disorientation of her environment, inability to distinguish between friends and strangers, inappropriate sexual behavior, and changes in her eating habits (Cohen, 1988).  The subject also suffered from dysarthria which resulted in rapid hand gestures near her mouth, constant mouthing of her fingers, and an excessively fast rate of speech.  In Cohen’s study, music at m.m. = 80 beats per minute was utilized in conjunction with a corresponding tapping movement of the fingers.  This type of pacing strategy has been recommended by speech pathologists in the treatment of dysarthria (as cited in Beukelman & Yorskton, 1981; Miller, 1982).  For those employing this pacing strategy, it requires clapping or counting one syllable on each finger as a form of rhythmic cuing in order to create a self-monitored rate of speech (Cohen, 1988).  It’s important to recognize that most of the subject’s musical abilities such as singing and matching tempo and rhythm were intact.  During baselining, the client’s rate of speech was analyzed by counting the number of syllables per second and averaged m.m. = 169.6.  Although, the subject’s speech was fragmented with frequent pauses between statements, she averaged 300 words per minute as opposed to the normal 190 words per minute (Cohen, 1988).

A metronome was utilized after each session to accurately measure the subject’s speech rate.  A cassette tape with the song “Hey Jude” by the Beatles and a cassette tape with conversational speech both played with the desired tempo of m.m. = 80 were used (Cohen, 1988).  Baseline data was collected over 5 consecutive sessions with 20-minute sessions each week.  Once the baseline was stabilized, a reversal design (ABACAC) was implemented. The A condition consisted of the baseline period and contained no independent variables.  The B treatment (music), which lasted for four consecutive sessions, added a tape consisting of three 30 second musical selections (“Hey Jude” at m.m. = 80).  Cohen asked the subject to sing along with the tape while tapping the beat on her legs with her hands.  Treatment C (functional speaking) was introduced and lasted four consecutive sessions.  Functional sentences such as, “May I have my medications, please?, “My name is…,” and “I miss my dad”  were utilized in which the subject was asked to repeat these sentences while tapping the beat on her legs (Cohen. 1988).

 Results of the study are as follows: results revealed that during the baseline period, the average metronomic rate of speech was 169.7.  The subject’s speech rate was reduced 11% during the music treatment.  However, the return to baseline caused a 5% increase in the rate of speech.  The introduction of the functional sentence tape caused a significant decrease of 28% from the original baseline with an additional 5% decrease in speech rate when a return to the third baseline was made (Cohen, 1988).  Overall, the subject’s speech rate was stabilized at m.m. = 122.  Extraneous factors that may have affected the study included the subject having two medication changes during the second and third baseline conditions and the addition of direct reinforcement of incompatible behavior (DRI) during the functional speaking treatment (Cohen, 1988). 

Effect of Rate Control on Speech Production and Intelligibility in Dysarthria

 Speech rate control is an effective technique for improving the intelligibility of individuals with dysarthric speech.  There are several rate control methods related to intelligibility in dysarthria and Nuffelen, De Bodt, Vanderwegen, Van de Heyning, and Wuyts (2010), conducted a study comparing seven rate control methods and their effect on articulation rate, speaking rate, and intelligibility in dysarthric speech.  The methods included were the following: speaking slower on demand, pacing board, alphabet board, hand tapping, and delayed auditory feedback with delays of 50 ms (DAF50), 100 ms (DAF100), and 150 ms (DAF150) (Nuffelen et al., 2010).   Their study included 27 participants (22 men and 5 women) with a mean age of 64 years ranging from ages 17-88 years of age.  In the case of hand tapping, subjects were asked to tap once for each syllable while uttering syllable per syllable.  Various speech tasks were utilized, the first being text passages.  For this task, 20 different passages that were comprised of simple sentences were used and subjects were asked to read randomly selected passages for at least 2 minutes (Nuffelen et al., 2010).  Second, two-minute speech samples were obtained in which each subject started with their habitual speaking rate followed by the seven rate control methods. Thirdly, the intelligibility of the speech samples was rated by three speech language pathologists who were not familiar with the text passages given to the subjects and who were also experienced in dysarthria and its treatment (Nuffelen et al., 2010). 

The effect of rate control on speaking rate showed that each rate control method resulted in a reduction of speaking rate of 9.3%.  In addition, the slowest mean speaking rates that were obtained were by hand tapping, alphabet board, and pacing board (Nuffelen et al., 2010).  The effect of rate control on articulation rate resulted in a reduction of articulation rate of 3.7% on average.  Similar to speaking rate, articulation rate was effectively reduced by hand tapping, alphabet board, and pacing board (Nuffelen et al., 2010).  The effects of rate control methods also had a significant effect on intelligibility.  In their study, each rate control method led to a significant increase in intelligibility in at least 1 participant.  Furthermore, the alphabet board, pacing board, and hand tapping were found to be the most effective rate control methods and increased intelligibility in 14 out of 27 participants (Nuffelen et al., 2010).  Overall, the researchers recognized that each rate control method had the potential to improve speech intelligibility, but alphabet board, pacing board, and hand tapping were discovered to be the most effective methods when applied to individuals with dysarthric speech.

Hand/Finger Tapping in Melodic Intonation Therapy (MIT)

It has been noted by clinicians that patients with nonfluent aphasia are able to sing words that they cannot speak.  Due to this knowledge, it has long been recommended to utilize melody and rhythm for the improvement of fluency in aphasic patients (Norton, Zipse, Marchina, Schlaugh, 2009). However, it was not until the 1970’s that a music-based treatment approach called Melodic Intonation Therapy was developed.  MIT has been one of the few accepted treatments for severe nonfluent aphasia.  It is “a treatment that uses musical elements of speech (melody and rhythm) to improve expressive language by capitalizing on preserved function (singing) and engaging language-capable regions in the undamaged right hemisphere (Norton et al., 2009, p. 431).”  Hand tapping, or rhythmic tapping, adds to MIT’s effectiveness because it may engage a right hemisphere sensorimotor network that controls both hand and mouth movements.  Furthermore, hand tapping is similar to a metronome’s purpose and thus helps pace the speaker and provides a continuous visual cue for syllable production (Norton et al., 2009). 

Since MIT was first introduced in 1973, the literature base supporting its effectiveness has grown drastically and other treatments have been used in conjunction with MIT (Morrow-Odom and Swann, 2013).  For example, Norton et al. (2009), studied two outcomes from two individuals with chronic, severe, nonfluent aphasia following left hemisphere stroke.  In this study, subject 1 had undergone the traditional MIT only, while subject 2 underwent MIT after completing speech repetition therapy (SRT).  SRT is a similar treatment approach to MIT but does not utilize intonation and hand tapping (Norton et al., 2009).  Treatment outcomes were measured using behavioral assessment and neuroimaging at pre- and post-treatment time points.  Both subjects “demonstrated increases in correct informational units when describing picture scenes, increases in the number of syllables produced per phrase, and improvements in confrontational picture naming following the completion of their treatments” (Morrow-Odom and Swann, 2013). However, it was MIT that demonstrated a greater improvement on all outcomes compared to the subject receiving SRT.  Thus, it was concluded that intonation and hand tapping were key components that contributed to a greater treatment success (Morrow-Odom and Swann, 2013).  Overall, not all clients will respond to MIT therapy, but in some cases, it has been considered to be effective in recovering speech for those with non-fluent aphasia.

Considerations and Contraindications

 As a clinician, when incorporating hand/finger tapping as a pacing strategy, it is imperative to assess and determine if the client’s muscle coordination is intact to effectively engage in the hand tapping movement needed for this particular therapy approach.  If so, it is recommended that hand/finger tapping be done with the client’s dominant and stronger hand (Mainka and Mallien, 2014).  It is also important that the purpose and goal of treatment be thoroughly explained to the client, especially to those presenting with spastic, ataxic, or mixed dysarthria who already have a slow speaking rate due to their dysarthria. Many times, they can feel that their speech is becoming worse due to the additional slowing down of their speech (Mainka and Mallien, 2014).

Conclusion

Hand/finger tapping is an external pacing strategy that attempts to control the rate of speaking for individuals with dysarthria.  It can be used alone or used in conjunction with rhythmic cueing strategies or music-based therapy, such as melodic intonation therapy.  The aforementioned studies have shown that hand/finger tapping is an acceptable therapy approach and has evidence-based research behind its effectiveness in the treatment of dysarthria.

References

American Speech-Language-Hearing Association.  (n.d.) Acquired Apraxia of Speech. Retrieved from https://www.asha.org/PRPSpecificTopic.aspx?folderid=8589934663& section=Treatment

Cohen, N. S. (1988).  The use of superimposed rhythm to decrease the rate of speech in a brain-damaged adolescent.  Journal of Music Therapy XXV (2), 85-93.

Duffy, Joseph R. (2013). Motor speech disorders: substrates, differential diagnosis, and management.  St. Louis, Missouri: Elsevier Mosby.

Freed, Donald (2020).  Motor speech disorders: diagnosis & treatment. Clifton Park, New York: Delmar Cengage Learning.

Garcia, J., Cannito M, & Dagenais, P.A. (2000). Hand gestures: perspectives and preliminary implications for adults with acquired dysarthria. American Journal of Speech-Language Pathology. 9(2), 107-115. DOI: 10.1044/1058-0360.0902.107

National Institute of Neurological Disorders and Stroke (2018) Kluver-Bucy Syndrome information page. Retrieved from https://www.ninds.nih.gov/Disorders/All-disorders/Klüver-Bucy-Syndrome-Information-Page

Norton, A., Zipse, L., Marchina, S., & Schlaug, G. (2009). Melodic intonation therapy: shared insights on how it is done and why it might help. Annals of the New York Academy of Sciences, 1169, 431-6. DOI: 10.1111/j.1749-6632.2009.04859.x

Nuffelen, G.W., De Bodt, M., Vanderwegen, J., Van de Heyning, P., & Wuyts, F. (2010). Effect of rate control on speech production and intelligibility in dysarthria. Folia Phoniatrica et Logopaedia. 62, 110-119.  DOI: 10.1159/000287209

Mainka, S. & Mallien, G. (2014). Rhythmic Speech Cueing (RSC). Retrieved from http://global.oup.com/booksites/content/9780199695461/13-Thaut-Chap13.pdfOdom-Morrow, K.L., & Swann, A.B. (2013). Effectiveness of melodic intonation therapy in a case of aphasia following right hemisphere stroke.  Aphasiology 27(11), 1322-1328. DOI: 10.1080/02687038.2013.817522