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:
MedStudents-Neurology
Cerebellar
Ataxia
Buspirone
in the treatment of cerebellar ataxia
Study
of brain stem and cerebellar involvement in multiple sclerosis
MS Glossary
All About Multiple Sclerosis