CSD 726: Assignment 7
Piper Doering
Spring, 2013
Why might Lee Silverman Voice Therapy techniques improve articulation, facial expressions,
and swallowing?
Lee Silverman Voice Therapy (LSVT) techniques emphasize increasing loudness and effort
through multiple, intense repetitions (Fox, Morrison, Ramig, & Sapir, 2002). In addition to
increased loudness and effort, LSVT may also improve patients’ articulation, facial expressions,
and swallowing functions. Following is an explanation of these findings, specific to patients with
Idiopathic Parkinson Disease (IDP).
Articulation is the process of shaping sound into phonemes through the movement of oral and
facial structures. Clients with IDP often have decreased amplitude and speed of orofacial
movement, affecting articulation precision (Fox et al., 2002). LSVT has improved articulation
function in this population. This improvement is demonstrated by changes in formant transition
duration, increased orofacial muscle movement, and decreased vowel centralization (Fox et al.,
2002). There are a couple of explanations for these changes. First, LSVT encourages increased
neural activity to orofacial muscles as a result of the increased vocal effort (Fox et al., 2002).
Second, increased loudness correlates with stable motor output, demonstrated by a decreased
spatiotemporal index (Fox et al., 2002). In other words, a patient using LSVT indirectly
decreases the variability in the space and time of his or her articulation movements by focusing
on loudness and effort, thus making articulation more precise.
Facial expression is used when people show emotion through the movement of their oral and
facial structures. This can increase in clients with IPD after LSVT. As in articulation, an increase
in neural activity is a possible explanation for this change. Focusing on vocal loudness may also
stimulate neural pathways that are associated with the regulation of emotion and vocal
expression (Fox et al., 2002). As a whole, neural changes can be supported through positron
emission tomography (PET) scans. PET scans conducted on clients using LSVT demonstrated
increased paralimbic activity and the neural circuits connecting these areas of the brain (Fox et
al., 2002). This data counters the explanation that successful therapy merely increases facial
expression due to patient happiness. In addition, patients who participated in alternative
treatments have not shown this similar increase in facial expression (Fox et al., 2002).
Swallowing involves the formation and movement of a bolus from the mouth to the esophagus.
LSVT is associated with improved swallowing functions in patients with IPD who had oraltongue and tongue-base disorders (Fox et al., 2002). In essence, the patients did not have the
strength and coordination for a successful posterior bolus transfer. LSVT has been associated
with improved tongue strength, thus improving swallowing function (Fox et al., 2002).
Articulation, facial expression, and swallowing are all secondary effects that may occur as a
result of LSVT. While loudness and vocal effort are the main focuses of therapy, the changes
that result in strength and speed of facial and oral musculature, in addition to the increased
stimulation to neural pathways, causes secondary effects to occur. Changes in articulation, facial
expressions, and swallowing have all been reported in literature.
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CSD 726: Assignment 7
How to counsel a patient with vocal tremor, who’s receiving a bilateral botulinum toxin
injection to her thyroarytenoid muscles, about what to expect in the first 4 weeks post-injection
Essential tremor of the voice (ETV) occurs when muscle groups associated with the vocal tract
periodically and unintentionally move in a rhythmic manner (Bové, Daamen, Rosen, Wang,
Sulica, & Gartner-Schmidt, 2006). Bilateral botulinum toxin injections to the thyroarytenoid
muscles are one option for ETV treatment. When a patient receives these injections, a clinician
must counsel her about what to expect in the first four weeks post-injection. Steps to counseling
are outlined below.
Starting from this point forward, the clinician should have a patient-friendly diagram of vocal
tract musculature, for the patient to reference. First the clinician should describe botulinum toxin
and the effects to the injected thyroarytenoid muscle. The aim of botulinum toxin is to denervate
the thyroarytenoid muscle by blocking acetylcholine at the neuromuscular junction (Sapienza &
Hoffman Ruddy, 2009). Thus, the patient should be aware that injections to the thyroaryteniod,
the muscle that helps to relax and contract her vocal folds, will temporarily be inhibited of
movement. This will be noticed immediately following injections, as the tremor resulting from
uncontrollable movement of the thyroarytenoids will be diminished (Sapienza et al., 2009).
Secondly, the patient must be informed of the varying effects the botulinum toxin has on ETV as
a result of the characteristics of this neurologically based voice disorder. Botulinum toxin
injections are beneficial in 50% to 65% of treated patients (Bové et al., 2006). For patients that
do benefit, voice quality improvements vary since muscles beyond the thyroarytenoid are often
affected. Intrinsic laryngeal, extrinsic laryngeal, pharyngeal, and respiratory muscles may all be
affected by ETV (Bové et al., 2006). Thus, bilateral injection to the thyroarytenoid muscles alone
may have minimal effects to voice quality with the continual tremor of other muscles.
Specific improvements the patient will notice immediately post-injection should be described in
consideration to the possible perceptual changes in her voice. Common voice characteristics
associated with EVT include pitch changes, loudness variations, and voice breaks (Sapienza et
al., 2009). These characteristics are expected to decrease following botulinum toxin injections,
resulting in a less shaky, smoother voice quality.
While the aim of botulinum toxin injections is for the patient’s symptoms of voice tremor to
decrease or be eliminated, the effects of the injections will be temporary. Over the four weeks
post-injection the patient may notice her symptoms of tremor gradually returning (Sapienza et
al., 2009). However, the timeline for when symptoms of tremor will return varies for every
patient. The patient should be informed that tremor-relief is dependent on how fast her affected
nerve endings recover from the injections, but that this period of time is typically three months
(Sapienza et al., 2009). More injections can follow, with similar results.
Before receiving botulinum toxin injections to the thyroarytenoids, a patient must be counseled
on what to expect four weeks post-injection. Information should be shared regarding a
description of botulinum toxin, the effects on the thyroarytenoids, the persistence of tremor
beyond the thyroarytenoid muscles, and the progressive return of EVT symptoms experienced
pre-injections. Effective counseling aims to increase patient awareness and comfort.
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CSD 726: Assignment 7
References
Bové, M., Daamen, N., Rosen, C., Wang, C-C., Sulica, L., & Gartner-Schmidt, J. (2006).
Development and validation of the vocal tremor scoring system. The Laryngoscope,116:
1662-1667.
Fox, C.M., Morrison, C.E., Ramig, L.O., & Sapir, S. (2002). Current perspectives on the Lee
Silverman Voice Treatment (LSVT) for individuals with idiopathic Parkinson disease.
American Journal of Speech-Language Pathology, 11, 111-123.
Sapienza, C.M. & Hoffman Ruddy, B. (2009). Voice disorders. San Diego, CA: Plural
Publishing, Inc. – Chapter 6: Neurologically based voice disorders (pp. 267-313).
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