Every body movement, from raising a hand to smiling, involves a complex interaction between the central nervous system (brain and spinal cord), nerves, and muscles. Damage to or malfunction of any of these components may result in a movement disorder.

Different types of movement disorders can develop, depending on the nature and location of the damage or malfunction, as in the following:

• Damage to the parts of the brain that control voluntary movement or the connections between the brain and spinal cord: Weakness or paralysis of the muscles involved in voluntary movements and exaggerated reflexes
• Damage to the basal ganglia (collections of nerve cells located at the base of the cerebrum, deep within the brain): Involuntary or decreased movements, but not weakness or changes in reflexes
• Damage to the cerebellum: Loss of coordination

Some movement disorders, such as hiccups, are temporary, usually causing little inconvenience. Others, such as Parkinson's disease, are serious and progressive, impairing the ability to speak, use the hands, walk, and maintain balance when standing.

Last full review/revision August 2007 by David Eidelberg, MD; Michael Pourfar, MD