Cerebellum - Pathology

Pathology

The most salient symptoms of cerebellar dysfunction are motor-related — the specific symptoms depend on which part of the cerebellum is involved and how it is disrupted. Damage to the flocculonodular lobe (the vestibular part) may show up as a loss of equilibrium and, in particular, an altered walking gait, with a wide stance that indicates difficulty in balancing. Damage to the lateral zone, or the cerebrocerebellum, results in problems with skilled voluntary and planned movements. This can cause errors in the force, direction, speed and amplitude of movements. Some manifestations include hypotonia (decreased muscle tone), dysarthria (problems with speech articulation), dysmetria (problems judging distances or ranges of movement), dysdiadokinesia (inability to perform rapid alternating movements), impaired check reflex or rebound phenomenon, and tremors (involuntary movement caused by alternating contractions of opposing muscle groups). Damage to the midline portion may disrupt whole-body movements, whereas damage localized more laterally is more likely to disrupt fine movements of the hands or limbs. Damage to the upper part of the cerebellum tends to cause gait impairments and other problems with leg coordination; damage to the lower part is more likely to cause uncoordinated or poorly aimed movements of the arms and hands, as well as difficulties in speed. This complex of motor symptoms is called "ataxia". To identify cerebellar problems, the neurological examination includes assessment of gait (a broad-based gait being indicative of ataxia), finger-pointing tests and assessment of posture. If cerebellar dysfunction is indicated, a magnetic resonance imaging scan can be used to obtain a detailed picture of any structural alterations that may exist.

The list of medical problems that can produce cerebellar damage is long: it includes stroke; hemorrhage; tumors; alcoholism; physical trauma such as gunshot wounds; and chronic degenerative conditions such as olivopontocerebellar atrophy. Some forms of migraine headache may also produce temporary dysfunction of the cerebellum, of variable severity.