Sudden involuntary contraction of muscle, a group of muscles, or a hollow organ such as the heart.Encyclopedia Entry for Spasm :Spasmodic dysphonia. The exact cause of spasmodic dysphonia is unknown. Sometimes is it triggered by psychological stress. Most cases result from a problem in the brain and nervous system that can affect the voice. The vocal cord muscles spasm, or contract, which causes the vocal cords to get too close or too far apart while a person is using their voice. Spasmodic dysphonia often occurs between ages 30 and 50. Women are more likely to be affected than men. Sometimes, the condition runs in the family.The voice is usually hoarse or grating. It may waver and pause. The voice may sound strained or strangled, and it may seem as if the speaker has to use extra effort. This is known as adductor dysphonia. Sometimes, the voice is whispery or breathy. This is known as abductor dysphonia. The problem may go away when the person laughs, whispers, speaks in a high-pitched voice, sings, or shouts. Some people have muscle tone problems in other parts of the body, such as writer's cramp.An ear, nose, and throat doctor will check for changes in the vocal cords and other brain or nervous system problems. Tests that will usually be done include: Using a special scope with a light and camera to view the voice box (larynx) Voice testing by a speech-language provider.There is no cure for spasmodic dysphonia. Treatment can only reduce the symptoms. Medicine that treats spasm of the vocal cord muscles may be tried. They appear to work in up to one half of people, at best. Some of these medicines have bothersome side effects. Botulinum toxin (Botox) treatments may help. Botulinum toxin comes from a certain type of bacteria. Very small amounts of this toxin may be injected into the muscles around the vocal cords. This treatment will often help for 3 to 4 months. Surgery to cut one of the nerves to the vocal cords has been used to treat spasmodic dysphonia, but it is not very effective. Other surgical treatments may improve symptoms in some people, but further evaluation is necessary. Brain stimulation may be useful in some people. Voice therapy and psychological counseling may help to reduce the symptoms in mild cases of spasmodic dysphonia. .Dysphonia - spasmodic; Speech disorder - spasmodic dysphonia.Central nervous system Central nervous system and peripheral nervous system.Blitzer A, Sadoughi B, Guardiani E. Neurologic disorders of the larynx.Encyclopedia Entry for Spasm :Spasmus nutans. Most cases of spasmus nutans begin between age 4 months and 1 year. It usually goes away by itself in several months or years. The cause is unknown, although it may be associated with other medical conditions. A link with iron or vitamin D deficiency has been suggested. In very rare cases, symptoms similar to spasmus nutans may be due to certain types of brain tumors or other serious conditions.Symptoms of spasmus nutans include: Small, quick, side-to-side eye movements called nystagmus (both eyes are involved, but each eye may move differently) Head nodding Head tilting.The health care provider will perform a physical exam of the child. The parents will be asked about their child's symptoms. Tests may include: CT scan of the head MRI scan of the head Electroretinography , a test that measures the electrical response of the retina (the back part of the eye).Spasmus nutans that isn't related to another medical problem, such as brain tumor, requires no treatment. If the symptoms are caused by another condition, the provider will recommend appropriate treatment.Usually, this disorder goes away on its own without treatment.Call for an appointment with your child's provider if your child has rapid, movements of the eyes, or head nodding. The provider will need to perform an exam to rule out other possible causes for the symptoms.Hertle RW, Hanna NN. Supranuclear eye movement disorders, acquired and neurologic nystagmus.