Movement disorders are diseases which are characterized by movement impairments of all kinds, ranging from too little to too much. The most prominent example of this kind of illness is Parkinson's Disease.
Parkinson's disease is a degenerative central nervous system (CNS) disorder, affecting speech, motor skills and other functions. Generally, it occurs in patients around age 55, but can occur earlier. Disease can be caused by a number of different things. In so-called idiopathic Parkinson's (ca. 75% of all cases), a decrease of nerve cells in the midbrain which are responsible for the formation of dopamine is found. Diagnosis occurs after clinical testing.
Therapy is comprised of so called dopamine agonists, medications which activate dopamine receptors. Other medications work to counter the loss of dopamine in the brain. In some cases, deep brain stimulation may be necessary.
Here you will find the Parkinson's section of the German Neurological Society's website http://www.dgn.org/11.0.html (German)