Certified Neuroscience Registered Nurse (CNRN) Practice Exam

Which syndrome is characterized by pure motor hemiparesis?

1. Corticobasal degeneration

2. Pure motor stroke

3. Lacunar stroke

4. Subcortical stroke

The correct answer is: Lacunar stroke

Pure motor hemiparesis is a syndrome that typically results from a specific type of stroke that affects the motor pathways in the brain without impacting sensory functions. In this context, the correct answer refers to a lacunar stroke, which occurs as a result of occlusion of small penetrating arteries that provide blood to the brain's deep structures. These small vessel diseases often lead to lesions in areas like the posterior limb of the internal capsule, which is crucial for motor control. Lacunar strokes often present with pure motor hemiparesis due to their nature of affecting a limited area within the brain, primarily targeting the neural pathways responsible for motor function. The condition is distinct because the motor impairments occur with relatively intact sensory and cognitive functions, which differentiates it from other types of strokes or neurological syndromes that could also affect motor functions. Thus, understanding the mechanism and presentation of lacunar strokes offers clarity on why they are associated with pure motor hemiparesis specifically.