In Brown-Sequard syndrome, which deficit pattern is typical?

• A. Ipsilateral hypertonic/paralysis and loss of vibration and proprioception; contralateral loss of pain and temperature
• B. Ipsilateral loss of pain and temperature; contralateral motor loss
• C. Bilateral loss of all sensation
• D. No motor deficits with preserved sensation

Answer: (A)

A unilateral spinal cord lesion on one side produces a characteristic pattern because different tracts have distinct crossing patterns. The corticospinal tract on the injured side is interrupted, leading to ipsilateral weakness with increased tone and brisk reflexes below the level of the lesion. The dorsal columns on the same side are also disrupted, causing ipsilateral loss of vibration, proprioception, and fine touch below the lesion. The pain and temperature fibers of the spinothalamic tract cross to the opposite side soon after entry, so a hemisection damages contralateral pain and temperature sensation starting a few segments below the lesion. This combination—ipsilateral motor weakness and dorsal column loss with contralateral loss of pain and temperature—defines Brown-Sequard syndrome.