Voice Therapy 

Voice therapy encompasses a myriad of techniques employed in the management schema for patients with voice disorders. These techniques may seek to eliminate potentially harmful vocal behaviors, alter the manner of voice production, and/or enhance vocal fold tissue healing following injury. Emerging data suggest that voice therapy is an effective and appropriate method of therapy either in itself or as a compliment to other treatment modalities (eg, surgery, medications).

The particular therapeutic regimen employed for a particular patient is highly variable and based on several key issues including: (1) vocal fold tissue health, (2) vocal demands of the patient, (3) baseline phonatory behaviors, and (4) patient compliance. Once these 4 factors have been evaluated, a customized voice therapy program is developed and contoured to address the vocal complaints and the demands of the patient. For example, a voice therapy program for a 70-year-old housewife is likely to vary significantly from that for a 30-year-old attorney, even in the presence of similar laryngeal appearance.

Simplistically, voice disorders may be divided into the following 3 categories: hyperfunctional, hypofunctional, and dysfunctional. In each of these cases, a vocal fold lesion and/or neurological abnormality may contribute to the voice disorder.

Hyperfunctional voice disorders, regardless of the presence of a vocal fold lesion, involve increased laryngeal and/or supralaryngeal muscle tension. The goal of therapy for these disorders is to decrease laryngeal and supralaryngeal muscle tension during voice production in an attempt to improve vocal efficiency. A benign vocal fold lesion may likely accompany hyperfunctional voice disorders. Therapy must not only target improved vocal efficiency but also enhanced resolution of the lesion. Evidence is emerging that "exercise" in the broad sense may alter wound healing events and facilitate lesion resolution. Therefore, customized therapies must be designed to treat patients who present with benign vocal fold lesions (eg, nodules, polyps) because these lesions are likely the manifestation of the wound healing response to phonotrauma.

In contrast, hypofunctional voice disorders (eg, unilateral vocal fold paralysis, parkinsonian dysphonia) typically respond to behavioral voice therapy techniques that improve glottal closure or augment vocal tract dynamics to enhance vocal output.^[1]

Voice therapy is also widely believed to be effective with patients who do not fall into either of the above categories. These patients have a dysfunctional voice disorder (eg, psychogenic dysphonias, conversion dysphonia, puberphonia) in that they are capable of producing a normal voice but do not use the vocal mechanism in a functionally appropriate manner. In addition, several populations of patients may benefit from voice therapy. As described in the following section, a unique form of voice therapy called "respiratory retraining" has been shown to be effective in the management of patients with a condition referred to as paradoxical vocal fold movement disorders. In this condition, the vocal folds inappropriately close during breathing, causing shortness of breath and/or cough. In addition, voice therapy may be beneficial in the transgender population in which the voice must be manipulated to correspond with the patient's gender identity.

A prerequisite to voice therapy is a referral from a voice care team, which typically involves an otolaryngologist and speech pathologist. This referral should evolve from a complete evaluation of the vocal mechanism including rigid and/or flexible laryngeal endoscopy. Stroboscopy may also be indicated for many patients to visualize vibratory motion. In addition, experiments conducted to examine if knowledge of the patient's clinical condition affects voice quality assessment concluded that only blind tests can provide reliable results.^[2] This thorough evaluation process permits for the customization of a voice therapy program based on vocal physiology.

Overview

Treatment for an injured voice historically involved periods of voice rest followed by a long list of behavioral practices the patient should or should not do, more commonly known as vocal hygiene therapy. In current practice, short periods of voice rest (3-7 d) are typically prescribed following vocal fold surgery, to resolve vocal fold swelling, or treat an acute vocal injury, such as a vocal fold hemorrhage.^[2] The objective is to avoid further vocal fold trauma and allow for tissue restoration and healing.^[3] Assuming the cause of the voice disorder is driven by an inefficient or traumatic manner of speaking, resting only provides a temporary resolution. Once speaking resumes, voice problems return. In addition to serious job-related consequences, long-term voice rest also has negative psychological effects.^[3]

In contrast to previous treatment, contemporary voice therapy is dynamic, including (1) general education (eg, vocal anatomy and physiology, patient diagnosis, treatment options, and prognosis), (2) establishing healthy vocal habits and identifying and avoiding vocally traumatic behaviors, and (3) modifying voice production by training vocal techniques to alter vocal patterns that contribute or maintain the voice problem. A comprehensive approach with all these components is likely to yield superior outcomes.^[4]

Current literature exploring patient adherence also suggests that the patient’s perception of the voice therapy process may play a large part in patient compliance and therapeutic outcomes. Methods that facilitate or develop the patient’s sense of self-reliance (eg, practicing at home), self-efficacy (eg, “I can do this.”), and a positive patient-therapist relationship (eg, motivational interviewing) are likely to increase the success of voice therapy.^[5] A review of each is provided below.

Indirect voice therapy

Indirect voice therapy is primarily educational and helps the patient identify factors that might be contributing to his or her voice problem. Standard intervention addresses environmental irritants, vocal use, and personal behaviors and might include instructing the patient on the effects of adequate hydration, avoidance of phonotraumatic behaviors (ie, yelling, excessive throat clearing), and adequate control of health issues such as laryngopharyngeal reflux, allergies, and/or asthma.

The majority of vocal fold injuries are thought to be caused by an inflammatory response of the vocal fold tissue, most often related to excessive and prolonged shearing forces on the vocal folds. Understandably, vocal hygiene guidelines are widely viewed as a crucial aspect of vocal recovery. However, research results on the effects of educational hygiene programs alone have been mixed. This may be related to the restrictive and, at times, unrealistic restrictions.^[6] Modifications to tailor the advice to the needs of the patient for a more “slimmed-down” approach have been suggested for better compliance.^[7] In general, it is advisable for therapists to use vocal hygiene education as a minimum, adding direct voice treatment protocols on an individualized basis.

Direct voice therapy

Direct voice therapy involves alteration of a patient's speaking technique by targeting different aspects of voice and/or speech production. This may include addressing a combination of pitch, loudness, intonation, phonation, breathing, and resonance. Although therapy techniques can vary from therapist to therapist, the main goal of a treatment program is to establish a phonation pattern that does not cause vocal damage, while meeting the needs of the patient’s daily vocal responsibilities. The frequency of therapy sessions varies widely depending on the diagnosis being treated and the patient’s skill level; however, many treatment plans call for 1-2 sessions per week for approximately 6-8 weeks. In the case of phonosurgery, therapy is usually limited to several sessions before surgery and resumption of therapy about 1-2 weeks after surgery.

Synopses of the most cohesive and widely studied therapeutic approaches are provided below. A properly trained voice clinician may use a variety of different techniques, merging indirect and direct voice therapy to customize a program to the patient. These descriptions are not all-inclusive, nor are they an instruction manual for the inexperienced clinician. Rather, each therapy is a summary of the therapeutic concepts behind that model.

Confidential voice therapy

Confidential voice therapy involves lowering the volume of the voice while using an easy, breathy voice quality, as if speaking “confidentially” to someone. It is used most commonly as an effective means of significantly reducing the pressure on the vocal folds during phonation for a limited period, after which a patient may return to a more functional volume of speech. This type of voice use may be indicated following an acute vocal fold injury or as a method of gradually resuming voice use following surgery. There is no particular structure to this type of treatment. The clinician may train the desired sound with models and subsequently shape confidential voice quality into conversation.

Resonant voice therapy

Resonant voice therapy trains the patient to produce an easy and resonant voice by attending to vibratory sensations in nasal and facial cavities (also known as “forward focus”). Studies suggest the resonant voice quality is produced with “barely touching” or “barely separated” vocal folds. This configuration reduces impact stress on the vocal folds while achieving optimal vocal output (volume and clarity).

This laryngeal posture is favorable for patients who present with laryngeal hyperfunction, as it trains the patient to produce the clearest and most prominent voice with little effort and decreased risk of injury. Patients train using sounds that facilitate a vibratory or “buzzy” sensation in the front of the face while maintaining awareness of an “easy voice.” This is then systematically shaped into speech tasks. Resonant voice therapy can be used as a method of treatment for patients with overly pressed or inadequate vocal closure alike.

A review of the current literature by Zeigler et al (2010) suggests that using resonant voice therapy either in generic form or a formalized program (eg Lessac-Madsen Resonant Voice Therapy [LMRVT]) is effective in treating high-risk occupational voice users, such as teachers or actors.^[8]

Vocal function exercises

Vocal function exercises (VFEs) are based on a physiologic approach, focusing on the principle of exercise to achieve optimal stamina, strength, and coordination of breath support, phonation, and resonance. It has been described as “taking your larynx to the gym” for improved balance in laryngeal musculature. The program is highly regimented, with exercises performed twice daily for 6 weeks. Steps, to be repeated twice, include (1) a vocal warm-up, (2) maximal pitch glides (high-to-low and low-to-high), and (3) maximal vowel prolongations at selected pitches.

All voicing is produced with the softest possible tone in “extreme forward focus.” Published studies have revealed VFE is an effective treatment for singers, teachers, and priests. Findings also suggest that VFE may improve symptoms related to presbylaryngis or the aging voice.^[9]

Accent method

The accent method involves producing easy voice with abdominal engagement in pulsations of breathflow. Initial stages of training involve rhythmic consonant sounds (called accents) in combination with body movements that aid in respiratory support for each accent. As increasingly complex accents are graduated into speech tasks, body movements are diminished. Advocates of the accent method report increased pulmonary output, reduced laryngeal muscle tension (even in severe cases of dysphonia), and a normalized vibratory pattern of vocal folds during phonation.

Digital laryngeal manipulation or circumlaryngeal manual therapy

The focus of laryngeal manipulation, circumlaryngeal manual therapy (CMT), or laryngeal massage is to treat muscular imbalances via massage and pressure points along the extrinsic laryngeal musculature. In this treatment modality, it is believed that excessive laryngeal muscle tension leads to inefficient voice use and an eventual breakdown of the mechanism.^{[10, 11]} Patients may report an array of symptoms, from generalized neck pain to more focal areas of tenderness. Treatment requires patient compliance and excellent palpatory skills from the therapist.

An initial palpation of the larynx is essential to assess laryngeal posture, muscle tone, anatomic irregularities, and pain or tenderness of the muscle tissue. Areas of focus may include superior suspensory muscles, hyoid position and musculature, lateral laryngeal movement and rotation, and thyrohyoid space and muscles. Additional observations of the patient’s general posture and head position are also helpful in evaluating possible triggers of musculoskeletal dysfunction. Under the management of a skilled practitioner, digital laryngeal manipulation can be extremely effective in treating even severe dysphonia.

Lee Silverman voice treatment

Lee Silverman voice treatment (LSVT) is a well-known and heavily researched voice therapy protocol. It was developed to address speech and voice problems that affect patients with Parkinson disease.^{[12, 13]} Among other characteristics, breakdowns in the ability to self-monitor effort in relation to speech motor control results in a significantly softer volume of speech. The LSVT program retrains or “recalibrates” self-perception of appropriate vocal loudness for improved intelligibility. This is achieved through completion of an intensive 4-week, 16-session program.

Tasks include sustained loud maximum phonation, maximal pitch glides, and carryover of high-effort, high-volume voice quality into conversation. This high-intensity, high-effort mode of delivery is thought to have a more global effect on the speech motor system, triggering improvements in vocal quality and in articulation, facial expression, and swallowing. More recent developments in this therapeutic modality include the effects of LSVT on dysarthria following traumatic brain injury/stroke and hypernasality, as well as the success of online delivery.

Respiratory retraining

Respiratory retraining (RR) focuses on strategies of relaxed throat breathing with increased awareness of abdominal breathing patterns. RR is useful for patients with chronic cough that is refractory to medical treatments, paradoxical vocal fold motion disorder, laryngospasm, or laryngeal irritation. It is often used in conjunction with vocal hygiene education such as hydration therapy and avoidance of laryngeal irritants. Behavioral programs may include relaxed inhalation with abdominal focus, breathing with resistance (eg using sustained sibilants on an exhale), and laryngeal postures that either voluntarily suppress a cough or control breathing issues.

In some cases, psychoeducational counseling may be helpful to facilitate “internalization” of the belief that patients’ symptoms are in response to stimuli, rather than a phenomenon outside of their control. The relaxed-throat breathing technique by Florence Blager is a well described and widely implemented program that encompasses many of the techniques described above. Activity-based breathing and inspiratory muscle strength training have also been used as respiratory training programs for high-level athletes with paradoxical vocal cord movement (PVFM).

In the broad categorization of voice disorders, voice treatment may be more or less effective based on the associated etiology and need for medical or surgical intervention. Below is a general description of when voice treatment is appropriate.

Functional voice disorders

Functional voice disorders are characterized by the presence of vocal symptoms without anatomical laryngeal abnormality. Muscle tension dysphonia (MTD) is the most common disorder in this category. A course of indirect and direct voice therapy is very effective in decreasing laryngeal hyperfunction associated with MTD.

During evaluation, it is often helpful to determine if the patient is able to improve voice quality with trials of direct voice therapy techniques. This is a strong indicator of future therapeutic success. However, the longer the presence of dysphonia, the more guarded the prognosis. Psychogenic dysphonias, such as conversion dysphonia, also fall into the category of functional voice disorders. Combination therapy with a trained speech-language pathologist (SLP) and a skilled mental health specialist can treat these disorders effectively.

Organic vocal fold disorders

Organic vocal fold disorders include, but are not limited to, vocal fold nodules, cysts, and polyps. Vocal nodules are small, commonly bilateral lesions of the superficial layer of lamina propria, often located at the junction of the anterior third and posterior two thirds of membranous vocal fold. Voice therapy is indicated as a first line of treatment for vocal nodules if they are not long-standing in duration and not extremely fibrotic in nature.

Cysts and polyps are also lesions of the superficial layer of the lamina propria. For optimal results, voice therapy is performed prior to and following phonomicrosurgery. In cases such as these, voice therapy is thought to improve vocal technique and decrease the likelihood of lesion recurrence.

Neurological voice disorders

Neurological disorders may be localized to the larynx or may be present as part of a widespread neurological condition. The most common disorders resulting in dysphonia are Parkinson disease, essential tremor, and spasmodic dysphonia.

Approximately 75% of people with Parkinson disease have speech and voice characteristics that affect their communication abilities. Lee Silverman Voice Treatment (LSVT) is among the most highly researched techniques used for speech symptoms of Parkinson disease.^{[12, 13]} Among other characteristics, people with Parkinson disease often present with reduced vocal loudness, slurred articulation, and “flat” facial affect. Studies confirm that people with Parkinson disease often have breakdowns in their ability to monitor self-effort, resulting in a significantly softer voice despite their perception of normal production. The LSVT program was developed to retrain, or “recalibrate” self-perceptions of appropriate vocal loudness for improved intelligibility. This is achieved over the course of an intensive 4 week, 16-session program. Treatment results include improved articulatory precision and mobility.

Spasmodic dysphonia is a focal dystonia affecting the laryngeal musculature; the most widely used treatment is localized injections of botulinum toxin A (BOTOX). These injections temporarily weaken the muscles, decreasing dystonic laryngeal muscle activity. The duration of weakness varies from patient to patient and often from injection to injection. Murry and Woodson (1995) suggest that behavioral voice therapy used in combination with botulinum toxin A injection therapy increases the effectiveness and duration of botulinum toxin A therapy.^[14]

Vocal fold immobility

Success of voice therapy in patients with unilateral vocal fold immobility is dependent on the position of the paralyzed vocal fold, the remaining vocal fold bulk, the tension present in the immobilized fold, the duration of the disorder, and surgical correction if performed. Patients with a paralyzed vocal fold in a medial position are more likely to have successful therapy than are patients with an immobile vocal fold in a lateral position.

Voice therapy for vocal fold paralysis historically involved rigorous pushing/pulling exercises. Paradoxically, these exercises can induce laryngeal hyperfunction, resulting in a voice disorder in addition to the original problem. Vocal function exercises, resonant voice therapy, challenge therapy (modified LSVT), postural/position alterations, or a combination of these are safer alternatives.

Chronic Cough

Chronic cough is characterized by a persistent, often nonproductive, cough that is refractory to medical management and lasts longer than 3-6 weeks. Similar to paradoxical vocal fold motion disorder (PVFMD), chronic cough has been associated with heightened neurosensory reflexes of the larynx, which are triggered by various stimuli.

Patients may cough in response to fumes or strong scents, smoke, temperature extremes, talking, and throat irritability. Research on cough triggers suggests that abnormal laryngeal sensation (laryngeal paraesthesia) is present in approximately 94% of chronic cough cases, with stimuli of talking, exercise, and shortness of breath as common triggers.

Speech pathology is thought to play an important role in the treatment of refractory cough. Treatment focuses on identifying sensations that precede the urge to cough, vocal hygiene, and specific training of suppression and distraction strategies. In addition, supportive counseling that refocuses the patient’s sense of self-efficacy may be helpful.

Like many other medical practitioners, speech pathologists may specialize in one area of treatment, such as patients with expressive language difficulties, articulation disorders, or swallowing problems. Voice therapy should only be performed by a licensed speech pathologist with training in voice disorders. Referring a patient to a speech language pathologist without training and experience in voice-specific therapy techniques can lead to ineffective treatment and high levels of frustration.Voice therapy is most effective when individualized to the patient’s unique symptoms, skill level, and lifestyle. Every patient presents with a completely different syndrome, regardless of the physiology. Individual therapists may approach the same disorder very differently but still achieve the same goals. With encouragement, compliance monitoring, and effective intervention, every patient has the potential to be successful in therapy.

Voice therapy is an essential component of treatment for many patients with voice disorders. In many cases, voice therapy is the primary treatment recommended for many patients. This article is far from a comprehensive review of all voice therapy techniques, but rather a cursory outline of some of the more salient issues involved in the therapeutic process. Voice therapy is individualized; the type of therapy can vary greatly from patient to patient and from clinician to clinician with similar levels of success. In conclusion, when performed by a certified speech language pathologist (SLP) with specific training and experience in voice disorders, voice therapy can be effective in helping many patients with voice disorders.