What does the head thrust test assess in patients with dizziness?

The head thrust test is specifically designed to evaluate vestibular function, which is critical in the context of diagnosing the causes of dizziness or balance disorders. During the test, the clinician rapidly turns the patient's head to one side while asking the patient to maintain their gaze on a fixed target. A normal vestibular system allows the eyes to stay focused on the target, as the vestibular mechanism compensates for head movements by stabilizing vision. If there is a deficit in vestibular function, the eyes will make a corrective saccade back to the target, indicating a failure of the vestibular system to maintain stable vision during head movements.

This test is particularly useful in differentiating between central and peripheral causes of dizziness. While factors such as cognitive function, ocular movement, and motor coordination might influence a patient's overall assessment in a clinical setting, they are not specifically evaluated by the head thrust test, making vestibular function the primary focus of this test.