Laryngeal dystonia is also known as spasmodic dysarthria. It is a rare condition that makes it difficult for patients to speak normally because it involves the muscles that control the vocal cords in the throat. Spasmodic dysarthria most often affects women and usually begins in middle age (between 30 and 60 years of age). There are two main types of spasmodic dysphonia: the most common type is called “inward” and causes the patient’s speech to sound staccato, strained and choked. The other type, called “adductor”, causes speech to sound breathy, like a whisper. About 2/3 of these patients have the adductor spastic dysarthria. The larynx (the “box” where speech is produced) is the top of the trachea. The larynx contains the vocal cords, the structures that allow people to speak. The muscles that control the vocal cords in the throat are called “laryngeal muscles”. The cause of laryngeal dystonia is not known. However, it is known that spasmodic dysarthria is caused by spasms of the muscles in the throat, so it is assumed that the condition is caused by a problem in an area of the brain that controls the movement of the vocal folds. If you have new speech problems that do not subside, you should be seen immediately! Doctors use a special tool called a “nasopharyngoscope” to look at the movement of the vocal cords to make a determination. The main treatment is currently Botulinum toxin type A injected into the muscles of the larynx, which helps the muscles relax and reduces the symptoms of spasmodic dysphonia. The efficacy of botulinum toxin type A in the treatment of spasmodic dysphonia has been recognized both nationally and internationally, especially in the inotropic spasmodic dysphonia. In 1984, botulinum toxin type A was first used in the treatment of laryngeal dystonia with remarkable results. After 12 years of treatment and follow-up of 900 patients with spasmodic dysarthria, American otolaryngologist Blitzer found that the treatment with low-dose botulinum toxin could significantly improve the speech disorder index, improve the articulatory function (reduce perturbation, fundamental frequency, and improve vocal spectrum characteristics), improve speech fluency, and prolong the maximum time of articulation. For inotropic spasmodic dysarthria, the onset of effect of botulinum toxin type A was 24 days on average, with a peak of 9 days, and lasted 151 weeks, restoring an average of 89.7% of normal function. The American Academy of Otolaryngology and Head and Neck Surgery has endorsed botulinum toxin type A as the treatment of choice for spasmodic dysphonia. Regarding safety, Botulinum toxin type A is generally safe for the treatment of spasmodic dysphonia as long as the target muscle is injected precisely. Common adverse effects include transient hoarseness, dysphagia and dyspnea. Adverse reactions are largely mild and reversible. Transient: “Transient” refers to a clinical symptom or sign that occurs once in a short period of time, often with an obvious trigger, such as after eating a certain food, taking a certain medication, receiving a certain clinical treatment or other factors that affect the body. As the trigger is removed, the symptom or sign disappears quickly. The term “transient” literally means that it passes in a flash, such as a transient headache, which is often overlooked. In clinical practice, “transient irritation” and “transient diarrhea” are usually seen.