Professional and Linguistic Assessments Board (PLAB) Practice Exam

What is the main characteristic of Weber's syndrome?

1. Hemiplegia with ipsilateral paralysis

2. Contralateral hemiparesis with oculomotor nerve palsy

3. Loss of proprioception and vibration sense

4. Unilateral hearing loss

The correct answer is: Contralateral hemiparesis with oculomotor nerve palsy

Weber's syndrome, also known as midbrain syndrome, is primarily characterized by contralateral hemiparesis due to the involvement of the corticospinal tract in the midbrain. This results in weakness or paralysis on the side of the body opposite to the lesion. In addition to this weakness, the syndrome features oculomotor nerve palsy, which affects the eye movements on the same side as the affected oculomotor nerve. This dual presentation is key to understanding Weber's syndrome, as it illustrates the impact on both motor function and ocular control. The presentation of contralateral hemiparesis alongside ipsilateral oculomotor nerve issues is crucial for diagnosis, emphasizing the involvement of specific brainstem regions. This combination aligns with the anatomical pathologies associated with the syndrome, particularly lesions in the ventral midbrain. While other options present potential neurological deficits, such as hemiplegia with ipsilateral paralysis or sensory losses, these do not accurately capture the distinctive features of Weber's syndrome. Each focuses on different neural pathways or structures, thereby confirming B as the correct answer characterizing this specific condition.