[Brachial presentation of spinal pseudochoreoathetosis. The result of proprioceptive information being processed in parallel]

The term pseudochoreoathetosis is used to refer to the choreoathetoid movements that are produced by alterations in the proprioceptive sensitivity due to damage it has suffered at some point along its course. Proprioceptive sensitivity is considered to go up as far as the cortex along the posterior cords of the spinal cord, which means that if they are injured in the cervical region there should be a sensory deficit in both the upper (UL) and lower limbs (LL).We describe five cases of transverse myelitis with localised cervical injury that selectively and mainly affected the posterior cords of the spinal cord. In the five patients there was selective involvement of the proprioceptive sensitivity in the UL respecting the LL and pseudochoreoathetoid movements of the limb that has been deafferented for proprioceptive sensitivity. The dissociation between the UL and the LL occurs because the spinocerebellar and spinocervical tracts take the proprioceptive information from the LL in parallel to the posterior cords, which receive the proprioceptive sensitivity from the UL.At present, the most widely accepted physiopathological mechanism explaining pseudochoreoathetosis consists in a failure in the integration of the sensory-motor afferences in the striatum, which causes faulty sensory-motor integration at this level and gives rise to pseudochoreoathetosis.