Spasticity is increased muscle contractions causing stiffness or tightness of the muscles that may interfere with movement, speech and walking. It’s usually caused by damage to the portion of the brain or spinal cord that controls voluntary movement. It may result from spinal cord injury, multiple sclerosis, cerebral palsy, stroke, brain damage caused by a lack of oxygen, severe head injury and metabolic diseases such as Lou Gehrig's disease (ALS).
Dystonia can be present in one part of the body, known as focal dystonia, or throughout the whole body, known as generalized dystonia. Focal dystonia may only occur during a movement or task. Generalized dystonia refers to dystonic movement that affects both legs and at least one arm, or the trunk in combination with at least one arm or leg. This type of dystonia can affect mobility as well as cause speech and swallowing difficulties.
Athetosis is characterized by slow, continuous, involuntary, writhing movements that happen at rest and can become worse by attempts to move. People with athetosis experience fluctuations in muscle tone – with muscle tone alternating between being floppy and extremely variable motion.
Chorea is characterized by involuntary movements that are abrupt, brief, irregular and unpredictable. People with mild chorea may appear fidgety or clumsy, while people with more severe choreiform movements may display wild, violent, and larger movements. Movements can affect various body parts and interfere with movement, speech and swallowing.