Brown-Sequard syndrome (BSS) is a rare neurological disorder characterized by a lesion on the spinal cord which results in weakness or paralysis (hemiparaplegia) on one side of the body and a loss of sensation (hemianesthesia) on the opposite side. BSS may be caused by a spinal cord tumor, trauma (such as a puncture wound to the neck or back), degenerative disease, ischemia (obstruction of a blood vessel), or infectious or inflammatory diseases such as meningitis, shingles, tuberculosis, or multiple sclerosis.

Generally treatment for individuals with BSS focuses on the underlying cause of the disorder. Early treatment with high-dose steroids may be beneficial in many cases. Other treatment is symptomatic and supportive.

From http://www.ninds.nih.gov/health_and_medical/disorders/brown-sequard.htm