Question

Describe Brown-Séquard syndrome and the sensory and motor losses that accompany it. In responses, describe the basis for these losses.

Answer 1

Brown-Sequard syndrome (BSS) is a rare neurological condition characterized by a lesion in the spinal cord which results in weakness or paralysis (hemiparaplegia) on one side of the body and a loss of sensation on the opposite side.

It may caused by spinal cord tumor, trauma , ischemia (obstruction of a blood vessel), or infectious or multiple sclerosis.

In dorsal column, sensations which are responsible for fine touch, vibration, two-point discrimination, and conscious proprioception would be affected on the same side of lesion because dorsal columns ascend ipsilaterally carrying the information from the lower half of body in the gracile fasciculus and the upper half of body in the cuneate fasciculus before they decussate in lower medulla, these are cause sensational loss.

In Dorsal and ventral spinocerebellar tracts are carrying sensations of unconscious proprioception, lesion affecting dorsal spinocerebellar tracts cause ipsilateral dystaxia and involvement of ventral spinocerebellar would cause contralateral dystaxia since these fibers ascend and cross to the opposite side.these cause loss of sensation.

The lesion to fasciculus gracilis or fasciculus cuneatus (dorsal column) results in ipsilateral loss of vibration and proprioception (position sense) as well as loss of all sensation of fine touch.The loss of the spinothalamic tract leads to pain and temperature sensation being lost from the contralateral side beginning one or two segments below the lesion.

These are the basis of sensory and motor losses.