neurologic disorders
Cerebellar Disorders
Introduction
Cerebellar disorders have numerous causes, including congenital malformations, hereditary ataxias, and acquired conditions. Symptoms vary with the cause but typically include ataxia (impaired muscle coordination). Diagnosis is clinical and often by imaging and sometimes genetic testing. Treatment is usually supportive unless the cause is acquired and reversible. (See also Overview of Movement and Cerebellar Disorders .) The cerebellum has 3 parts: Archicerebellum (vestibulocerebellum):It includes the flocculonodular lobe, which is located in the medial zone. The archicerebellum helps maintain equilibrium and coordinate eye, head, and neck movements; it is closely interconnected with the vestibular nuclei. Midline vermis (paleocerebellum):It helps coordinate trunk and leg movements. Vermis lesions result in abnormalities of stance and gait. Lateral hemispheres (neocerebellum):They control quick and finely coordinated limb movements, predominantly of the arms and hands. There is growing consensus that in addition to coordination, the cerebellum controls some aspects of memory, learning, and cognition. is the archetypal sign of cerebellar dysfunction, but many other motor abnormalities may occur (see table Signs of Cerebellar Disorders ). 