What is (are) myoclonus-dystonia ?
Myoclonus-dystonia is a movement disorder that typically affects the upper half of the body. Individuals with this condition experience quick, involuntary muscle jerking or twitching (myoclonus) that usually affects their arms, neck, and trunk. Less frequently, the legs are involved as well. More than half of affected individuals also develop dystonia, which is a pattern of involuntary muscle contractions that causes twisting and pulling movements of specific body parts. The dystonia associated with myoclonus-dystonia may affect a single part of the body, causing isolated problems such as a writer's cramp in the hand, or it may involve multiple areas of the body. Rarely, people with this condition have dystonia as their only symptom.  The movement problems usually appear in childhood or early adolescence, and myoclonus is typically the initial symptom. Myoclonus may be triggered by movement or stimulation of the affected body area, stress, sudden noise, or caffeine. In some cases, the myoclonus gets worse over time; in other cases, people experience a spontaneous improvement (remission) of their symptoms. It is unclear why the movement abnormalities improve in some people but not in others.  People with myoclonus-dystonia may have an increased risk for developing psychological conditions such as depression, anxiety, panic attacks, and obsessive-compulsive disorder (OCD).