Professional and Linguistic Assessments Board (PLAB) Practice Exam

What does unilateral spastic paresis and loss of proprioception/vibration sensation with loss of pain and temperature sensation on the opposite side indicate?

1. Multiple sclerosis

2. Brown-Sequard syndrome

3. Guillain-Barré syndrome

4. Cerebral palsy

The correct answer is: Brown-Sequard syndrome

Unilateral spastic paresis alongside a loss of proprioception and vibration sensation on one side of the body, combined with a loss of pain and temperature sensation on the opposite side, indicates a particular neurological condition known as Brown-Sequard syndrome. This syndrome occurs due to a hemisection (partial damage) of the spinal cord, which can result from trauma, tumors, or demyelinating diseases. In this condition, the pathways for proprioception and vibration, which ascend ipsilaterally (same side) in the spinal cord, are affected on the same side as the lesion. Meanwhile, the pathways for pain and temperature sensation cross over to the opposite side at the level of the spinal cord and thus are lost on the side of the body opposite to the lesion. Therefore, the combination of symptoms aligns perfectly with the characteristic presentations of Brown-Sequard syndrome, where there is a hemiparesis of spastic nature and disparate sensory loss in a distinct pattern. Other conditions mentioned do not produce the same specific combination of symptoms. Multiple sclerosis may lead to various neurological deficits due to demyelination but does not typically present in this particular unilateral and crossed sensory fashion. Guillain-Barré syndrome is characterized by acute inflammatory polyneurop