Spasmodic dysphonia
Spasmodic dysphonia, also known as laryngeal dystonia, is a disorder in which the muscles that generate a person's voice go into periods of spasm.
[1] Triggers may include an upper respiratory infection, injury to the larynx, overuse of the voice, and psychological stress.
[1] The underlying mechanism is believed to typically involve the central nervous system, specifically the basal ganglia.
[6] 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.
[7] It is commonly reported by people with spasmodic dysphonia that symptoms almost only occur on vocal sounds that require phonation.
[6] It is hypothesized this occurs because of an increase in sporadic, sudden, and prolonged tension found in the muscles around the larynx during phonation.
[6] Although the exact cause of spasmodic dysphonia is still unknown, epidemiological, genetic, and neurological pathogenic factors have been proposed in recent research.
[14] 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.
The pathophysiology underlying dystonia is becoming better understood as a result of discoveries about genetically based forms of the disorder, and this approach is the most promising avenue to a long-term solution.
"[19] 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”.
[25][24] A team of professionals including a speech–language pathologist, an otolaryngologist, and a neurologist, are typically involved in spasmodic dysphonia assessment and diagnosis.
[26] The speech–language pathologist conducts a speech assessment including case history questions to gather information about voice use and symptoms.
[25] Following the speech assessment, the otolaryngologist conducts a flexible transnasal laryngoscopy to view the vocal folds and activity of the muscles controlling them in order to eliminate other possible causes of the voice disorder.
[24] In spasmodic dysphonia, producing long vowels or speaking sentences results in muscle spasms that are not observed during other vocal activities such as coughing, breathing, or whispering.
[citation needed] Because spasmodic dysphonia shares many characteristics with other voice disorders, misdiagnosis frequently occurs.
[28] The movements that are found in this disorder are typically rhythmic in nature, as opposed to the muscle spasms of spasmodic dysphonia.
[25] Diagnosis of spasmodic dysphonia is often delayed due to these challenges, which in turn presents difficulties in choosing the proper interventions.
[31] As the name suggests, these spasms occur in the adductor muscles of the vocal folds, specifically the thyroarytenoid and the lateral cricoarytenoid.
[31] As the name suggests, these spasms occur in the single abductor muscle of the vocal folds, called the posterior cricoarytenoid.
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.
[35] Botulinum toxin (Botox) is often used to improve some symptoms of spasmodic dysphonia through weakening or paralyzing the vocal folds, thus preventing muscle spasms.
[34][32] Some transient side effects observed in adductor spasmodic dysphonia include reduced speaking volume, difficulty swallowing, and a breathy and hoarse voice quality.
[42] Laryngeal manual therapy, which is massaging of the neck and cervical structures, also shows positive results for intervention of functional dysphonia.
In 1871, Ludwig Traube coined the term 'Spastic Dysphonia' while writing a description of a patient who suffered from a nervous hoarseness.
[47] 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.
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.
Aronson described that adductor SD suffered from decreased loudness, and a mono-tonality, with a choked, strain-strangled voice quality.
[49][50] Initial surgical efforts to treat the condition were published in 1976 by Herbert Dedo and involved cutting of the recurrent laryngeal nerve.
