Structural Changes in Vocal Folds
+ Vocal Fold Bowing
Vocal fold bowing is a condition that develops secondary to muscle atrophy of the thyroarytenoid muscle. Vocal fold bowing is most frequently seen in the elder population and is generally thought to be part of the normal aging process. It may also be referred to as presbylarynges. When vocal folds are bowed, they often do not close completely as they should, resulting in a spindle-shaped glottic closure configuration. The voice of a person with bowed vocal folds may be breathy and/or weak. This condition may also be seen in conjunction with other laryngeal disorders/pathologies, such as with a paralyzed vocal fold.
Bowing resultant from age-related changes and muscle weakness is typically treated with voice therapy designed to re-strengthen and re-balance the laryngeal musculature. Occasionally, a filler is injected into one or both vocal folds to increase tissue mass and improve glottic closure.
+ Laryngeal Myasthenia
The term laryngeal myasthenia refers to generalized muscle weakness in the laryngeal area. Laryngeal myasthenia is often associated gaps in glottic closure (anterior, posterior, spindle), which allows too much air to escape past the vocal folds when they are vibrating. Normal vocal folds move in a mirror image of each other, but with laryngeal myasthenia, asymmetrical movement is often present thus creating variability in voice quality. Laryngeal Myasthenia is treated through direct restrengthening of the laryngeal musculature through voice therapy. No surgical intervention is required with this disorder.
Presbylaryngeus means “aging voice,” and is thought to be a voice disorder that develops during normal processes of laryngeal aging of the larynx, including decreased breathing efficiency, loss of elasticity of the vocal fold cover, and possibly deterioration of the tone of the vocal fold body. Also, during the aging process, the supple cartilages of the larynx become more rigid and bone-like. The effects on voice due to these aging changes are usually decreased loudness, pitch wavering, and decreased voice quality. Presbylaryngeus appears to begin after the age of 65 and may be forestalled in aging speakers in excellent physical condition and/or speakers who have professional voice training and have remained active vocal users. Voice rehabilitative therapy may improve voice quality dramatically in patients with presbylaryngeus unassociated with other medical problems.
+ Reinke's Edema and Polypoid Degeneration
Reinke’s edema occurs when the area known as Reinke's space becomes filled with viscous fluid due to long-standing trauma. In its most severe form, the entire membranous portion of the vocal folds become infiltrated with thick, gelatinous fluid, and gives them the appearance of enlarged, fluid-filled bags or balloons. This extreme form is called polypoid degeneration. In some cases, polypoid degeneration may become so severe that the glottic airway may become partially obstructed by the vocal folds. Both Reinke’s edema and polypoid degeneration are most often caused by chronic irritation from smoking.
Unlike other laryngeal pathologies, Reinke's edema and polypoid degeneration tend to result in consistent changes in voice quality, including dysphonia (hoarseness), characterized by low pitch and a husky hoarseness. This voice quality has traditionally been described as a "whiskey" or “smoker’s” voice. Treatment for polypoid degeneration is usually surgical excision. If the patient continues to smoke, Reinke’s edema/polypoid degeneration may re-occur. Therefore, patients are advised to stop smoking prior to undergoing surgical management. Voice therapy is valuable both preoperatively in identifying the causes for the pathology and postoperatively for reestablishing good vocal hygiene and improved voice production.
Acute and Chronic
The term laryngitis is used to describe an inflammation (swelling) of the vocal fold mucosa (cover) causing mild to severe dysphonia (hoarseness) with lowered pitch and intermittent breaks in voice. In severe cases, aphonia (complete loss of voice) may result. The cause of acute laryngitis is unknown, but is usually associated with upper respiratory viruses and bacterial infections. The most effective treatments for acute laryngitis include external and internal hydration, antibiotics if prescribed, and rest. Occasionally, a cough suppressant may be prescribed to limit additional damage to the vocal folds. Because many patients will not feel pain with repeated coughing, they may unknowingly injure their voices further because of they are not aware of the potential vocal fold damage from severe or prolonged coughing.
Chronic (ongoing) laryngitis is a condition of long standing laryngeal mucosa inflammation, viscous (thick, sticky) mucus, and tissue lining thickness not associated with infection. Voice quality can range from mild to severely dysphonic depending upon the severity of the mucosa and epithelial change. Other symptoms include laryngeal fatigue (tired voice) and non-productive coughing and throat clearing. The causes of chronic laryngitis include (but are not limited to): repeated episodes of acute laryngitis, vocal misuse and abuse, smoking, poor hydration, air pollutants, airborne allergies, the use of dehydrating medications, gastroesophageal reflux disease, and repeated vomiting associated with bulimia. The typical treatment for chronic laryngitis is to identify and eliminate potential causative factors. Voice therapy is often very useful in identifying specific reasons for the prolonged hoarseness and helping patients develop strategies to modify these harmful elements.
+ Vocal fold Nodules
Vocal fold nodules are one of the most common benign (non-cancerous) vocal fold lesions. Nodules are typically the result of voice abuse and misuse over a period of time. The chronic impact on the vocal fold mucosa caused by inappropriate phonotory habits often results in callous-like lesions. These lesions are usually bilateral (occur on both vocal folds) and vary in size from as small as a pinhead to as large as a pea. Nodules can occur at any age but occur frequently in both male and female children and in female adults. In most cases, nodules occur in people who frequently engage in phonotraumatic voice use, such as yelling/screaming, speaking over loud noise, harsh throat clearing/coughing, and/or singing too much or too loudly. They may also occur in untrained singers using inappropriate vocal technique. Nodules are rarely present in adult males. The effects on the voice vary depending upon how big the lesions are, how long they have been on the vocal folds, and any accompanying laryngeal inflammation.
The first line of management for vocal nodules is voice therapy. When nodules are removed surgically without the benefit of voice rehabilitation therapy, they may quickly recur. Even the chronic nodule may resolve when the appropriate management program is followed. When nodules do not respond to therapy for the patient who has been compliant with voice therapy, then surgical management may be required followed by post-surgical voice rehabilitation.
+ Vascular Lesions
Vocal Hemorrhage, Hematoma, and Varix
Vascular vocal fold lesions, including hemorrhage, hematoma, and varix occur due to some traumatic (usually sudden onset) injury to the small blood vessels of the vocal fold. Often, a hemorrhage occurs when a small blood vessel on the top surface of the vocal fold breaks causing bleeding into Reinke's space. A hematoma is the accumulation of blood that has leaked from the vessel. A varix is a mass of blood capillaries that appears as a small, longstanding "blood blister" that has hardened over time. It may also appear as a blunt end of a varicose vein, seen on the surface of the vocal fold after the hemorrhage has resolved.
All of these resulting injuries create stiffness in the mucous membranes. In the most severe cases, scarring of the vocal fold cover may occur. This scarring may cause significant sudden onset of severe hoarseness at the time of the bleed. Often the hoarseness lasts for a long period after the injury. The effects on voice vary, depending upon the extent and length of time since the onset. A varix in the nonprofessional voice is usually not cause for concern. However, even this slight disruption in normal vocal fold function may be significant for those who depend on their voices professionally.
The treatment of choice is strict voice rest, which, in most cases, results in spontaneous resolution of the hematoma. Conservative voice use, taking vocal naps and markedly limiting voice use, may be recommended. Other treatment for these vascular lesions may include a rapid course of steroids, or, in the case of an unresolved varix, micro excision of the lesion using careful laser vaporization. Voice therapy following resolution of these lesions is useful to restore voice quality, endurance, and range.
Cancer of the larynx (laryngeal carcinoma) is potentially the most devastating of all laryngeal pathologies due to the life threatening implications of the disease and the effect on vocal communication. The most common symptom of this pathology is persistent hoarseness. Vocal symptoms will vary from a very mild to severe dysphonia depending upon the location and the extent of the tumor. Sensations of laryngeal pain or referred pain to the ear may be present in later stages in the development of the disease. In advanced disease, the extent of the tumor may create both airway compromise or swallowing problems.
Laryngeal cancer in its early stages has one of the best rates of successful treatment of any type of cancer. Most laryngeal carcinomas are the squamous cell type and originate from the cover of the vocal fold. If the lesion develops further, it will invade into deeper layers of the vocal fold. Laryngeal carcinoma is thought to be caused by chronic irritation of the laryngeal epithelium and mucosa by chemical agents such as tobacco smoke and alcohol, but may have other causes. Carcinoma can also occur in other sites of the larynx external to the true vocal folds.
Whenever a suspicious lesion is identified in the laryngeal area, a surgical biopsy is conducted to excise a tissue sample for histopathological analysis, and a definitive diagnosis. Once the presence of malignancy is confirmed, treatment options may include surgical excision, radiation therapy, chemotherapy, or a combination approach
+ Congenital and acquired webs
Webs of the vocal folds occur when there is a tissue bridge between the two vocal folds at the very front portion (anterior). Congenital (from birth) webs arise when the vocal folds fail to separate during the tenth week of embryonic development. Webbing may cause various degrees of shortness of breath and stridor (noisy breathing), depending upon the extent of the web. The voice qualities of children with congenital webs will range from normal voice to a severe dysphonia, depending on the length and thickness of the web. In some cases, virtually no effects are noted in either breathing or voice quality. Treatment typically includes surgery to separate the web. Voice therapy may have a role in post-operative rehabilitation, to encourage proper development of voice pitch and quality.
Acquired webs may develop in the post-operative period following vocal fold surgeries that involve the anterior membranous portion of the folds, or following a vocal trauma. These micro webs, also called synechias, occur when irritation of the anterior commissure heals as a small fibrotic web. The effect of this micro web on voice quality can be variable, and surgical management is occasionally warranted, especially in elite performers.
Epithelial hyperplasia is a general term that describes abnormal changes in the mucous membranes of the vocal folds. These changes usually occur in response to combination of hyperfunctional voice use and chemical irritants, such as tobacco use and alcohol. Two vocal fold pathologies seen in adults, typically classified under epithelial hyperplasia, are leukoplakia and hyperkeratosis. These lesions appear as irregular thickening of the vocal fold cover and usually have some discoloration associated with the tissue irregularity. Lesions that go beyond the outermost layer of the vocal folds and invade the intermediate and deep layers are at high risk for signaling early carcinoma. The lesions increase the mass and stiffness of the cover of the vocal fold, usually resulting in change in vocal quality.
Leukoplakia (shown at right) is a pre-diagnostic term that means "white plaque" and describes the appearance of a thick white substance that covers the vocal folds in diffuse patches, usually on the top surface of the vocal fold. The pathology of leukoplakia may include both benign and malignant lesions. Hyperkeratosis is a layered buildup of keratinized cell tissue and consists of a horny overgrowth of irregular margins on the vocal folds.
Both lesions are treated as cautionary signs for possible future malignancy. People who have such lesions are instructed to avoid future exposure to chemical inhalants, tobacco smoke, and other irritants including alcohol. Usually, a biopsy and surgery will be conducted to confirm the diagnosis and remove lesion from the vocal fold cover. Voice therapy is often is used to assist in recovery of voice quality and assist in modifying the behaviors that contributed to the causes
+ Sulcus Vocalis
A vocal fold sulcus is a ridge or depression that runs along the medial (middle) surface of the membranous portion of the vocal fold. The sulcus often causes the vocal fold edge to appear bowed. Sulci usually occur bilaterally though a unilateral sulcus can occur. When a sulcus is present, the vibrating cover of the vocal fold becomes stiff. There is no clear cause for sulcus vocalis. However, one proposed theory is that vocal fold sulci develop following abnormal embryologic maturation of the vocal fold cover, resulting in a furrowed appearance of the membranous vocal fold edge. Acquired onset of sulcus vocalis is also possible, especially following laser surgery, aging changes, and vocal fold paralysis.
Voice quality that results from a vocal fold sulcus may be mild to severely dysphonic depending on the stiffness of the vocal fold and the size of the glottal gap caused by the sulcus. Treatment attempts involving surgical techniques for removing the sulcus have been attempted with mixed results. Direct voice therapy focused on increased vocal efficiency without excessive strain has yielded voice improvement for some patients. No characteristic treatment of choice has emerged for this pathology.
+ Recurrent Respiratory Papillomatosis (RRP)
Recurrent Respiratory Papillomatosis is a rare disorder with wart-like growths (papillomas) that can be anyway in the voice box (larynx) and respiratory tract, most often involving the larynx including the vocal folds. Due to the often invasive nature of the Papilloma, the vocal quality in these patients is typically severely dysphonic. Because of the diffuse locations and rapid spread of the papilloma, medical treatments are aggressive, including interferon therapy and laser excision. Multiple laser surgeries are often required to control these tumors, and these repeat procedures can create vocal fold scarring. The biggest concern with papilloma the potential that growth of these lesions can obstruct the airway, leading to compromised respiration. Papillomas are wart-like lesions that develop on the surface of the vocal folds, but often invade deeper into the vocal folds layered structure and even into the vocalis muscle. Papillomas are persistent tumors (typically benign) thought to be caused by viruses, although no clear etiology has been established. They tend not to be transmitted between family members, nor has any genetic pattern been identified. Papillomas are usually found equally in both genders of children usually appearing between the ages of two and four years. Less frequently, the disorder can begin in adult years, and the incidence of adult onset is increasing. In children, the development of papilloma usually decreases with age and often papillomas may disappear altogether during puberty.
Although aggressive medical and surgical management is necessary for the treatment of these lesions, direct voice therapy may be beneficial in some patients as well. There is some evidence that papilloma spread and severity may be reduced in patients who avoid hyperfunctional voice use and reduce excessive medial compression of the vocal folds. Additionally, treatment may be required to assist patients in re-establishing optimal voice quality after surgery, especially when vocal folds are scarred due to multiple procedures.
Systemic Disease Contributors to Laryngeal Pathology
+ Laryngopharyngeal Reflux (LPR) and Gastroesophageal Reflux Disease (GERD)
Reflux esophagitis may result in both hoarseness and throat pain, especially if the irritation of the laryngeal mucosa is so great that granuloma tissue or contact ulcers have formed. Pharmaceutical management with over-the-counter or prescription acid reducers, coupled with a behavioral anti-reflux protocol, can generally bring symptoms under control. Recently, otolaryngologists have prescribed aggressive medical treatment of LPR using medications, including proton pump inhibitors (PPIS) and H2 blockers augmented with antacids. Other behavioral aspects of an anti-reflux protocol may include recommendations for changes in diet, losing excess weight, elimination of caffeine, alcohol, and other substances that can aggravate or inhibit digestion, eliminating consumption of carbonated beverages, wearing loose clothing that does not bind the midriff, elevating the head of the bed at night, and avoiding unnecessary bending for activities such as bowling or gardening.
+ Endocrine Influences
Thyroid disorders affect the entire chemical and emotional balance of the body, so medical, intellectual, and affective influences are all possible. Hyperthyroidism results from excessive secretions of the thyroid gland, which is managed either through surgical excision or radioactive iodine treatment. Hypothyroidism, or reduced thyroid hormone production, may be treated medically using thyroid replacements. Thyroid function also affects voice production, but the predicted vocal outcomes are not clear. Various physical signs and perceptual attributes have been associated with hypothyroidism, including hoarseness, low pitch, coarse, and gravelly vocal symptoms due to thickened or edematous vocal folds. Other patients with this diagnosis have reported a persistent, unexplained dry cough. Perceptual features of hyperthyroidism include slight vocal instabilities, including "shaky" voice, breathy quality and reduced loudness. Because the voice disorder arises from a primary medical etiology, treatment is referred back to the appropriate medical specialist.
Sex Hormone Imbalances
In females, ongoing cyclic changes that fluctuate with puberty onset, pregnancy, menstrual cycle, and menopause may alter voice production during certain times. During menstruation, for example, the resulting vocal fold swelling may result in hoarseness, reduced pitch and loudness range, and loss of stability of phonation. In the post-menopausal years, female fundamental frequency and other structural changes in the vocal fold appear more prominent, affecting voice quality and endurance.
As a general rule, hormonal imbalances produce the greatest effect on vocal pitch. Virilization is the abnormal secretion of androgenic hormones, resulting in male gender characteristics in females. The vocal effects are low pitch, hoarseness, and occasionally voice breaks. Other specific hormone therapies, including estrogen replacement, androgens, testosterone, and oral contraceptives may alter voice quality. This sensitivity to hormonal changes is more common in females than in males. Behavioral voice therapy can be used to augment the "feminine" quality of voice and speech. Treatment with estrogen or other hormonal therapy may improve voice quality, but pitch changes are usually permanent.
+ Connective Tissue Diseases
Voice disorders seem to occur in persons with connective disease, but without other obvious contributing etiologies (e.g., vocal abuse, laryngeal pathology). Although there is little research about the potential effects of these diseases on laryngeal health and voice quality, clinicians who work in medical settings are familiar with the potential for voice change and deterioration in patients with connective tissue disorders. Connective tissue is a complex mixture of proteins that provide strength and elasticity to the skin, joints, and blood vessel walls. Connective tissue diseases predominantly affect women.
Due to the effect on tissue elasticity and strength, diseases such as rheumatoid arthritis (RA), Ehlers-Danlos syndrome, systemic lupus erythematosus (SLE), Sjogren’s syndrome, scleroderma, mixed connective tissue disease, and other autoimmune disorders may contribute to voice problems, as well as breathing problems. The changes in voice quality are not predictable, and certainly not every patient with these diagnoses will exhibit voice complaints. Most commonly, patients who are referred to a voice clinic with these disorders describe throat pain during talking, symptoms of vocal fatigue, loss of voice quality, endurance, or range. Ehlers-Danlos syndrome may contribute to shortness of breath in some patients as the laryngeal cartilages may not open sufficiently during inhalation.
Disease management and control is essential, as well as adequate hydration. However, voice therapy may be indicated and beneficial for improving voice quality and efficiency, as well as training to optimize breathing through laryngeal control exercises. The benefit of therapy is best determined by obtaining a videostroboscopic laryngeal exam. The finding of bamboo nodules, a yellowish usually transverse band of thickened tissue across the middle one-third of the true vocal folds can confirm the presence of a connective tissue disorder.
+ Pharmaceutical Effects on Voice
The effects of medications on voice performance and vocal function have not been explored exhaustively but a listing of some of the most common medications and their possible effects on voice can be found at www.ncvs.org.
Disorders of Voice Use
+ Muscle Tension Dysphonia
Muscle tension dysphonia is a term used to describe a disturbance of the coordination of the muscles of the larynx and breathing patterns needed to support ease of voicing. This may occur in varying degrees and characterized by variable symptoms of voice disruption. It is accompanied by observable tension or stiffness of the neck, jaw, shoulders, and throat. Often, patients with muscle tension dysphonia will report periodic pain in the sites of the larynx, neck, and other areas. Some patients may experience a sudden onset of almost complete loss of voice in the absence of illness. Behavioral voice rehabilitative therapy is very useful for relieving symptoms and restoring appropriate vocal technique for improved speaking.
+ Ventricular Phonation (Plica Ventricularis)
This occurs when a great amount of muscle tension above the vocal folds is created in the laryngeal area causing an approximation of the false, or ventricular, vocal folds. In the extreme case, the ventricular folds may actually be the source of vibration for voice production instead of the true vocal folds. The voice quality of ventricular phonation is typically a moderate to severe dysphonia characterized by low pitch, roughness, and strain. When true vocal fold vibration is physically possible, ventricular phonation can be improved or even eliminated through treatment including counseling and vocal rehabilitation through direct voice therapy.
+ Vocal Fatigue
Vocal fatigue is a frequent descriptor for a set of symptoms including deteriorated vocal quality or hoarseness, decreased endurance, loss of frequency and intensity control, and complaints of effortful, unstable, and/or ineffective voice production. The sensation of fatigue or muscle ache may accompany vocal fatigue. These symptoms typically worsen with extended periods of voice use.
+ Vocal Abuse and Misuse
These terms have long been subject to disagreement and dispute by voice professionals, and other labels have been proposed, including "phonotrauma," and "repetitive strain injury." The essential components of vocal abuse and misuse are prolonged, effortful, and maladaptive vocal behaviors, usually based on excessively loud or aggressive voice production, sharp glottal attack (voice onset), inappropriate technique for voice or singing, and aggressive laryngeal vegetative maneuvers, including throat clearing, coughing, or grunting. Some forms of abuse and misuse rise from at-risk situations or environments, including the need to talk above loud ambient noise, the need to talk for long periods of time, or unhealthy vocal demands placed on persons through external occupational demands. Vocal abuse and misuse often result from poor or ineffective training in vocal technique, including insufficient respiratory support, excessive laryngeal tension during phonation, and failure to achieve proper oral resonant focus. Across time, the aggregate effect of these poor vocal behaviors, whether produced knowingly or unknowingly, is traumatic injury to the vocal fold cover, sometimes to the extent that benign lesions will be formed.
+ Psychogenic Conversion Dysphonia or Aphonia
Stress and tension can induce a psychological conversion reaction that will manifest itself as hoarseness or changes in vocal quality. In a conversion dysphonia, this voice problem may result in complete voice loss. Most patients will respond quickly to direct voice therapy with combination psychotherapy.
The laryngeal mechanism goes through a dramatic change in both males and females during puberty. The male voice lowers about one octave during pubescence and the female voice lowers two to three semitones. When this acoustic change does not take place following the normal physical maturation, the male is said to have a functional falsetto and the female a juvenile or child-like voice. The voice qualities associated with these pathologies are typically mild dysphonias characterized by high pitch, low intensity, and breathiness. Common complaints are associated with the inability to shout, to compete with background noise, and voice fatigue. Voice therapy designed to engage the vocal musculature appropriately is the treatment of choice with these disorders.
Neurogenic Voice Disorders
+ Spasmodic Dysphonia
Spasmodic dysphonia remains a curious and unresolved voice disorder, due to its uncertain etiology and treatment potential. Spasmodic dysphonia is a descriptive term for a family of symptoms, all of which include some form of strained, strangled, and effortful voice production. The cause of this disorder has been debated for many years. Recent research has demonstrated strong evidence that spasmodic dysphonia has a neurologic origin and should be considered a focal dystonia specific to the larynx and similar to other dystonias such as blepharospasm and torticollis. Theories abound, but neither definitive etiology nor structural defect has been identified.
+ Adductor and Abductor types
There are two principle types of spasmodic dysphonia: adductor type and abductor type. Adductor spasmodic dysphonia is the most common type, and results in a severely hyper-functional voice, including a "strained-strangled" quality, multiple pitch or voice breaks and occasional voicing "blocks" of tension or effort that interrupt the continuity of phonation. Intermittent periods of normal voicing may occur during speech production, during both laughter and angry outbursts of speech, and while singing. Some patients are able to reduce the frequency and severity of the spasms when talking at a pitch level that is slightly higher than normal. The majority of patients with adductor spasmodic dysphonia find it difficult, if not impossible to shout. Many patients with adductor type spasmodic dysphonia complain of physical fatigue, tightness of the neck, back, and shoulder muscles and shortness of breath due to their efforts to phonate through the tightened glottis. The severity of the symptoms of adductor spasmodic dysphonia varies within and among individuals. Some patients experience only a very mild interruption in normal phonation, while others may be rendered voiceless by the severity of the spasms. Abductor spasmodic dysphonia is a virtual "mirror image" of the adductor type. Instead of the vocal folds spasming together (adductor SD), the vocal folds spasm apart creating an involuntary moment of no voice, which is accompanied by a burst of air. Voice is characterized by involuntary voice breaks and intermittent aphonia, with uncontrolled prolonged bursts of breathy phonation. Voice onset may appear normal, and then loss of voice ensues with continued speaking. The vocal fold spasms appear to occur primarily during the production of unvoiced consonants (such as /p/, /f/, /s/) and can occur during all positions within words, on whole words, and on several words in succession. Often, patients report that their voices improved when they were angry, increased their intensity, or altered their pitch. Voice quality worsened when they were anxious or fatigued.
The prevalence of spasmodic dysphonia is relatively low, approximately 1 per 100,000 population. The disorder is said to occur somewhat more in women than men with the most common onset in middle age. Rarely, symptoms of spasmodic dysphonia can occur in adolescence. Some patients experience a rapid onset associated with the occurrence of a traumatic event. Others report a more gradual onset following hoarseness associated with an upper respiratory infection. Still others appear to present with an idiopathic spasmodic dysphonia. The severity of the vocal symptoms appears to peak within the first year following the onset of the disorder.
Many patients with spasmodic dysphonia have experienced long and discouraging searches for many years, first for a diagnosis of the disorder and then for a treatment to cure or reduce the symptoms. To this end patients may have seen several otolaryngologists, neurologists, psychologists, and speech pathologists. They may have received voice therapy, psychotherapy, psychological counseling, stress reduction interventions, drug therapies, EMG and thermal biofeedback, relaxation training, acupuncture, hypnosis, and faith healing. Unfortunately, none of these approaches has proved to be consistently effective in relieving the vocal symptoms. In the past two decades, a specialized form of chemodenervation has been used with good success to treat spasmodic dysphonia. Percutaneous injections of botulinum toxin (BOTOX) into the intrinsic laryngeal muscles have provided temporary reprieve from symptoms of spasmodic dysphonia.
+ Organic (Essential) Vocal Tremor
Essential tremor is a central nervous system disorder that is characterized by rhythmic tremors (4 to 7 cycles/second) of various body parts including the larynx. Tremor may involve the head, arms, neck, tongue, palate, face, and larynx in isolation or in combinations. In some patients, the tremor may only be observed when the affected body part is being used (intentional tremor), whereas other patients will exhibit the tremor behavior even at rest (resting tremor). Vocal tremors involve not only tremor of the intrinsic muscles of the larynx but also, on occasion, the extrinsic laryngeal, pharyngeal, and palatal muscles, as well as the muscles of the diaphragm, chest wall, and abdomen. The onset of essential tremor is usually gradual and begins most commonly in the fifth or sixth decade of life. The disorder occurs most frequently in males, is often hereditary, and is often accompanied by other neurological signs. Laryngeal tremor is most noticeable during prolonged vowels as the rhythm of the tremor is easily discerned. Connected speech may be negatively affected as well. In some cases, the tremor is so severe that it causes voice stoppages like those of spasmodic dysphonia. Indeed, these two disorders, which may co-exist, are often mistaken for one another. Some patients with essential tremor have benefitted from injection of Botox into the vocal folds, but not all do, and some have side effects from the injection that make it difficult to swallow. Voice therapy for essential vocal tremor can help make the voice sound more stable and make it feel easier to speak for some people with vocal tremor, but more research is needed in this area to determine who the best candidates for therapy are and what the best treatment approaches are for these individuals.
+ Other Neurologic Disorders
Neurologic disorders that affect the larynx do not occur in isolation and, as such, voice impairments often accompany other disordered motor speech functions including respiration, articulation, resonance, and prosody. Indeed, many of the hallmark diagnostic signs and symptoms are based on clusters of perceptual attributes and deficits of the speech pattern. The range and type of neurologic voice problems are as varied as the underlying dysarthrias. Some of the neurologic diseases that may also affect voice include (but are not limited to): myasthenia gravis, multiple sclerosis, Huntington’s chorea, Parkinson’s disease, Amyotrophic Lateral Sclerosis (Lou Gehrig’s disease). The treatment options for voice therapy differ depending on the effects the individual diseases on the respiratory, phontory, and resonance systems.
+ Vocal Cord Dysfunction (VCD)
Although vocal cord dysfunction (also known as paradoxical vocal fold movement or inducible laryngeal obstruction) is not a primary vocal complaint, the disorder is marked by inappropriate closure (adduction) of the vocal folds during the breathing cycle, usually with inhalation. This results in inhalatory stridor, which can be confused with upper respiratory disorders such as asthma. Patients will perceive episodic shortness of breath, often during periods of exercise. Although the episodes are typically self-limiting, they have the potential to create airway distress and are often perceived as frightening by patients. In severe and very rare cases, the disorder may result in chronic dyspnea, requiring a tracheotomy. The etiology for vocal cord dysfunction is unknown, but a large percentage of patients with these symptoms have other respiratory diagnoses, including asthma, allergies, or frequent upper respiratory infections. Other etiologies associated with this disorder include esophageal reflux, panic/anxiety disorders, and neuromuscular dyskinesia. Recent evidence suggests that some latent differences in laryngeal movements are detectable in persons with vocal cord dysfunction even during asymptomatic periods. Treatment for vocal cord dysfunction is frequently successful, using behavioral techniques to interrupt the cycle of adductor inhalatory motion, and to restore the normal respiratory pattern with vocal fold opening (abduction). Depending upon the patient profile, this behavioral treatment approach must be augmented with anti-reflux medication and psychological intervention, as warranted.
+ Tracheal Stenosis
Constriction or narrowing of the windpipe (trachea), which is located just below the vocal folds is referred to as tracheal stenosis. People with tracheal stenosis may experience shortness of breath, wheezing, stridor, cough, and recurrent pneumonitis. There are multiple causes of stenosis including congenital, neoplastic, infectious and inflammatory. The most common etiology is trauma caused by intubation. Diagnosis of this problem may include direct laryngoscopy, videostroboscopy, bronchoscopy, CT scan, MRI, and/or traditional X-ray. There is no behavioral treatment for tracheal stenosis, and when constriction is severe, tracheal dilation, laser surgical intervention, or tracheal resection is indicated.