Spasmodic dysphonia

Symptoms of spasmodic dysphonia can come on suddenly or gradually appear over the span of years. They can come and go for hours or even weeks at a time, or remain consistent. Gradual onset can begin with the manifestation of a hoarse voice quality, which may later transform into a voice quality described as strained with breaks in phonation. These phonation breaks have been compared to stuttering in the past, but there is a lack of research in support of spasmodic dysphonia being classified as a fluency disorder. It is commonly reported by people with spasmodic dysphonia that symptoms almost only occur on vocal sounds that require phonation. Symptoms are less likely to occur at rest, while whispering, or on speech sounds that do not require phonation. It is hypothesized that this occurs because of an increase in sporadic, sudden, and prolonged tension found in the muscles around the larynx during phonation. This tension affects the abduction and adduction (opening and closing) of the vocal folds. Consequently, the vocal folds are unable to retain subglottal air pressure (required for phonation) and breaks in phonation can be heard throughout the speech of people with spasmodic dysphonia. Regarding types of spasmodic dysphonia, the main characteristic of spasmodic dysphonia, breaks in phonation, is found along with other varying symptoms. The voice quality of adductor spasmodic dysphonia can be described as "strained-strangled" from tension in the glottal region. Voice quality for abductor spasmodic dysphonia can be described as breathy from variable widening of the glottal region. Vocal tremor may also be seen in spasmodic dysphonia. A mix and variance of these symptoms are found in mixed spasmodic dysphonia. Symptoms of spasmodic dysphonia typically appear in middle-aged people, but have also been seen in people in their twenties, with symptoms emerging as young as teenage years. == Cause ==

Although the exact cause of spasmodic dysphonia is still unknown, epidemiological, genetic, and neurological pathogenic factors have been proposed in recent research. Risk factors include: • Being female • Being middle aged • Having a family history of neurological diseases (e.g., tremor, dystonia, meningitis, and other neurological diseases) • Stressful events • Upper respiratory tract infections • Sinus and throat illnesses • Heavy voice use • Cervical dystonia • Childhood measles or mumps • Pregnancy and parturition It has not been established whether these factors directly affect the development of spasmodic dysphonia, but they could be used to identify at-risk patients. However, a recent study that examined the mutation of these three genes in 86 SD patients found that only 2.3% of the patients had novel/rare variants in THAP1, but none in TUBB4A and TOR1A. Evidence of a genetic contribution for dystonia involving the larynx is still weak, and more research is needed in order to establish a causal relationship between SD and specific genes. SD is classified as a neurological disorder. However, because the voice can sound normal or near normal at times, some practitioners believe it to be psychogenic, originating in the affected person's mind rather than from a physical cause. This was especially true in the 19th and 20th centuries. However, another study found the opposite, with SD patients having significantly less psychiatric comorbidity compared to VFP patients: "The prevalence of major psychiatric cases varied considerably among the groups, from a low of seven percent (1/14) for spasmodic dysphonia, to 29.4 percent (5/17) for functional dysphonia, to a high of 63.6 percent (7/11) for vocal cord paralysis." A review in the journal Swiss Medicine Weekly states that "Psychogenic causes, a 'psychological disequilibrium', and an increased tension of the laryngeal muscles are presumed to be one end of the spectrum of possible factors leading to the development of the disorder". Alternatively, many investigations into the condition feel that the psychiatric comorbidity associated with voice disorders is a result of the social isolation and anxiety that patients with these conditions feel as a consequence of their difficulty with speech, as opposed to the cause of their dysphonia. The opinion that SD is psychogenic is not upheld by experts in the scientific community. SD is formally classified as a movement disorder; it is a type of focal dystonia known as laryngeal dystonia. == Diagnosis ==

Diagnosis of spasmodic dysphonia requires a multidisciplinary team and consideration of both perceptual and physiological factors. There is currently no universally accepted diagnostic test for spasmodic dysphonia, which presents a challenge for diagnosis. Additionally, diagnostic criteria have not been agreed upon as the distinguishing features of this disorder have not been well-characterized. The speech–language pathologist conducts a speech assessment including case history questions to gather information about voice use and symptoms. Some parameters can help guide the clinician towards a decision. In muscle tension dysphonia, the vocal folds are typically hyperadducted in a constant way, not in a spasmodic way. Additionally, the voice difficulties found in spasmodic dysphonia can be task specific, as opposed to those found in muscle tension dysphonia. Adductor spasmodic dysphonia is the most common type. Adductor spasmodic dysphonia Adductor spasmodic dysphonia (ADSD) is the most common type, affecting around 87% of individuals with SD. As the name suggests, these spasms occur in the adductor muscles of the vocal folds, specifically the thyroarytenoid and the lateral cricoarytenoid. Abductor spasmodic dysphonia Abductor spasmodic dysphonia (ABSD) is the second most common type, affecting around 13% of individuals with SD. In ABSD, sudden involuntary muscle movements or spasms cause the vocal folds to open. As the name suggests, these spasms occur in the single abductor muscle of the vocal folds, called the posterior cricoarytenoid. The vocal folds cannot vibrate when they are open. The open position of the vocal folds also allows air to escape from the lungs during speech. As a result, the voices of these individuals often sound weak, quiet, and breathy or whispery. As with adductor spasmodic dysphonia, the spasms are often absent during activities such as laughing or singing, but singers can experience a loss of range or the inability to produce certain notes of a scale or with projection. Mixed spasmodic dysphonia Mixed spasmodic dysphonia is the most rare type. Mixed spasmodic dysphonia involves both muscles that open the vocal folds and those that close them and, therefore, has features of both adductor and abductor spasmodic dysphonia. Some researchers believe that a subset of cases classified as mixed spasmodic dysphonia may actually be ADSD or ABSD subtype with the addition of compensatory voice behaviors that make it appear mixed. This further adds to the difficulty in achieving accurate diagnosis. Whispering dysphonia A fourth type has also been described. This appears to be caused by mutations in the TUBB4 gene on the short arm of chromosome 19 (19p13.2–p13.3). This gene encodes a tubulin gene. The pathophysiology of this condition has yet to be determined. == Treatment ==

There are a number of potential treatments for spasmodic dysphonia, including Botox, voice therapy, and surgery. Botulinum toxin Botulinum toxin (Botox) is often used to improve some symptoms of spasmodic dysphonia through weakening or paralyzing the vocal folds, thus preventing muscle spasms. However, it remains a choice for many people due to the predictability and low chance of long term side effects. It results in periods of some improvement, with the duration of benefit lasting for 10–12 weeks on average before symptoms return to baseline. Repeat injection is required to sustain good vocal production, as results are only temporary. Some transient side effects observed in adductor spasmodic dysphonia include reduced speaking volume, difficulty swallowing, and a breathy and hoarse voice quality. While treatment outcomes are generally positive, it is presently unclear whether this treatment approach is more or less effective than others. However, as it is difficult to distinguish between spasmodic dysphonia and functional dysphonias, and misdiagnosis is relatively common, trial of voice therapy is often recommended before more invasive procedures are tried. and others report success in more severe cases. Laryngeal manual therapy, which is massaging of the neck and cervical structures, also shows positive results for intervention of functional dysphonia. Surgery If other measures are not effective, surgery may be considered; however, evidence to support surgery as a treatment for SD is limited. Surgical approaches include recurrent laryngeal nerve resection, selective laryngeal adductor denervation-reinnervation (SLAD-R), thyroplasty, thyroarytenoid myectomy, and laryngeal nerve crush. Recurrent laryngeal nerve avulsion is a more drastic removal of sections of the nerve, and has positive outcomes of 80% at three years. SLAD-R is effective specifically for adductor spasmodic dysphonia, for which it has shown good outcomes in about 80% of people at 8 years. Thyroplasty changes the position or length of the vocal folds. ==History==

In 1871, Ludwig Traube coined the term 'Spastic Dysphonia' while writing a description of a patient who suffered from a nervous hoarseness. In 1895, Johann Schnitzler used the term "Spastic Aphonia", which is now called abductor SD, and "Phonic Laryngeal Spasms", now called adductor SD. Hermann Nothnagel followed by calling the condition "Coordinated Laryngeal Spasms", while Fraenkel coined the term "Mogiphonia" as a slowly developing disorder of the voice, in which is characterized by the increasing of vocal fatigue, the spasmodic constriction of the thorat muscles, and pain around the larynx. A comparison was made to "mogigraphia", which we now know as "Writer's Cramp". In 1899, William Gowers described functional laryngeal spasms whereby the vocal cords were brought together with too much force while speaking. This was contrasted to Phonic Paralysis, where the speaker's vocal chords could not be brought together during the action of speech. He reported in agreement with Fraenkel, that the vocal symptoms are most closely compared to Writers Cramp. Gowers reported and described a case by Gerhardt, where the patient had suffered from Writer's Cramp, and had learned to play the flute at the age of 50. Blowing the flute caused laryngeal spasms and a voice sound unintended by the patient, accompanied by contractions of the arm and mouth. This disorder was termed "Spastic Dysphonia", and as it was not a disorder with spasticity, was renamed to what is now called, "Spasmodic Dysphonia", by Arnold Aronson in 1968. In earlier works, Aronson performed Minnesota Multiphasic Personality Inventory screening and helped to establish SD as not being a Psychiatric Disorder, after reviewing psychiatric interviews of SD patients. Aronson formally characterized the two types of SD, the adductor, and abductor forms. Aronson described that adductor SD suffered from decreased loudness, and a mono-tonality, with a choked, strain-strangled voice quality. A vocal tremor was also often heard with a slowed speech rate. this was compared to what is seen in Essential Tremor. Initial surgical efforts to treat the condition were published in 1976 by Herbert Dedo and involved cutting of the recurrent laryngeal nerve. == Notable cases ==

• Scott Adams (1957-2026), creator of the comic strip Dilbert • Johnny Bush, country and western musician and songwriter • Keath Fraser, Canadian author who has documented the challenges and treatment of his condition in the book The Voice Gallery: Travels With a Glass Throat (2002) • Chip Hanauer, American hydroplane racing driver • Rodney Hicks, American Broadway, film, and TV performer • Kaori, Japanese voice actor • Robert F. Kennedy Jr., 26th Secretary of Health and Human Services • Mary Lou Lord, indie folk musician • Andy MacWilliams, radio broadcaster for the Cincinnati Stingers, Chicago Black Hawks, and Cincinnati Cyclones. • Benny Martin (1928–2001), American bluegrass fiddler, affected from 1980 to 1997 • Darryl McDaniels of the rap group Run DMC • Jenny Morris, New Zealand-born Australian pop, rock singer-songwriter • Petra Pau, one of the vice-presidents of the German Bundestag. • Jeff Pegues, Chief National Affairs and Justice Correspondent at CBS News • Diane Rehm, American public radio talk show host • Aleesha Rome, causing her to quit her singing career. • Jimmie Rodgers, Popular singer with his hits Honeycomb, Kisses Sweeter Than Wine, Secretly, etc. • Gail Strickland, an American actress • Mark Stuart, American Christian rock musician, of Audio Adrenaline • Linda Thompson, British folk-rock musician == References ==