Diagnosis of<unk>  requires a multidisciplinary team and consideration of both perceptual and physiological factors. There is currently no universally accepted diagnostic test for<unk> , 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. A team of professionals including a speech-language pathologist, an otolaryngologist, and a neurologist, are typically involved in<unk>  assessment and diagnosis. The speech-language pathologist conducts a speech assessment including case history questions to gather information about voice use and symptoms. This is followed by clinical observation and perceptual rating of voice characteristics such as voice breaks or strain, which are selectively present in normal speech over other voice activities such as whispering or laughing. Symptoms also vary across types of<unk> . For example, voiced sounds are more affected in adductor<unk> , while unvoiced sounds are more affected in abductor<unk> . Following 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. In<unk> , producing long vowels or speaking sentences results in muscle spasms which are not observed during other vocal activities such as coughing, breathing, or whispering. To evaluate the individual for any other neurological problems, this examination is followed up with an assessment by the neurologist. Voice quality symbol The voice quality symbol for<unk>  is ꟿ. Differential diagnosis Because<unk>  shares many characteristics with other voice disorders, misdiagnosis frequently occurs. A common misdiagnosis is muscle tension dysphonia, a functional voice disorder which results from use of the voice, rather than a structural abnormality. Some parameters can help guide the clinician towards a decision. In muscle tension dysphonia, the vocal folds are typically hyperadducted in constant way, not in a<unk>  way. Additionally, the voice difficulties found in<unk>  can be task specific, as opposed to those found in muscle tension dysphonia. Being able to differentiate between muscle tension dysphonia and<unk>  is important because muscle tension dysphonia typically responds well to behavioural voice treatment but<unk>  does not. This is crucial to avoid providing inappropriate treatment, but in some cases a trial of behavioural voice treatment can also be helpful to establish a differential diagnosis.<unk>  can also be misdiagnosed as voice tremor. The movements that are found in this disorder are typically rhythmic in nature, as opposed to the muscle spasms of<unk> . It is important to note that voice tremor and<unk>  can co-occur in some patients. Differential diagnosis is particularly important for determining appropriate interventions, as the type and cause of the disorder determine the most effective treatment. Differences in treatment effectiveness are present even between the types of<unk> . Diagnosis of<unk>  is often delayed due to these challenges, which in turn presents difficulties in choosing the proper interventions. Types The three types of<unk>  <unk>  are adductor<unk> , abductor<unk> , and mixed<unk> . A fourth type called whispering dysphonia has also been proposed. Adductor<unk>  is the most common type. Adductor<unk>  Adductor<unk>  (ADSD) is the most common type, affecting around 87% of individuals with<unk> . In ADSD, sudden involuntary muscle movements or spasms cause the vocal folds (or vocal cords) to squeeze together and stiffen. As the name suggests, these spasms occur in the adductor muscles of the vocal folds, specifically the thyroarytenoid and the lateral cricoarytenoid. These spasms make it difficult for the vocal folds to vibrate and produce voice. Words are often cut off or are difficult to start because of the muscle spasms. Therefore, speech may be choppy but differs from stuttering. The voice of an individual with adductor<unk>  is commonly described as strained or strangled and full of effort. Surprisingly, the spasms are usually absent while laughing, speaking at a high pitch, or speaking while singing, but singers can experience a loss of range or the inability to produce certain notes of a scale or with projection. Stress, however, often makes the muscle spasms more severe. Abductor<unk>  Abductor<unk>  (ABSD) is the second most common type, affecting around 13% of individuals with<unk> . 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<unk> , 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<unk>  Mixed<unk>  is the most rare type. Mixed<unk>  involves both muscles that open the vocal folds and those that close them and therefore has features of both adductor and abductor<unk> . Some researchers believe that a subset of cases classified as mixed<unk>  may actually be ADSD or ABSD subtype with the addition of compensatory voice behaviours 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.
Spasmodic dysphonia
Stuttering
Muscle tension dysphonia
Dysphagia lusoria
Odynophagia
Anotia
Pseudodysphagia
Hallucinatory palinopsia