Cerebellar Ataxia is caused by lesions of the cerebellum region of the brain or the connections to it in the cerebellar peduncles, the pons or the red nucleus.
Cerebellar Ataxia is a relatively common symptom of multiple sclerosis but is also associated with other conditions. These include an idiopathic (cause unknown) condition most usually in children which often follows a viral infection such as chicken pox and a genetic condition known as Miller Fisher Syndrome.
In Cerebellar Ataxia, afferent nerve transmissions to the cerebellum are disturbed which affects coordination and muscle reactions. The symptoms include:
Hypotonia - defective posture maintenance, diminished resistance to passive limb movements and delay in responses to such rapid imposed movements. Hypotonia is tested with Holmes' sign.
Incoordination - delays in initiating responses in limbs, errors in the range and force of movement or dysmetria, and errors in the rate and regularity of movements. This is manifest in an inability to perform rapid alternating movements - dysdiadochokinesia
Action or Intention tremor - inability to perform small movements accurately producing jerky movements. This most pronounced during termination of movement which leads to an action tremor as the limb approaches the target.
Lesions of the midline vermis and fastigial nuclei often result in nystagmus, gait ataxia and unstable stance. The most severe disturbances are produced by lesions of the superior cerebellar peduncle and the deep nuclei.
Cerebellar Ataxia links:
Buspirone in the treatment of cerebellar ataxia
Study of brain stem and cerebellar involvement in multiple sclerosis
Source details
Author: Paul Jones
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