What is the X in X-mas?
dystonia dys·to·ni·a (dĭs-tō'nē-ə)
Abnormal tonicity of tissue.
movement disorder characterized by the involuntary and repetitive contraction of muscle groups, resulting in twisting movements, unusual postures, and possible tremor of the involved muscles. As the disorder persists, movement may affect other muscle groups. Although dystonias may occur in families or sporadically, many are secondary to other disorders as reactions to medications; for example, one of the most common dystonias is induced by levodopa, a drug used in the treatment of Parkinson disease.