Angular vestibular function assessment: Multiaxial Head Impulse Test

Abstract

Introduction: The Head Impulse Head test represents a quick and simple technique for perioheral vestibular function assessment, by means of exploring the vestíbulo-ocu­lar reflex. It is usually performed on the horizontal semicircular canals planes, but it can also explore the anterior and posterior canals. Aim: To assess the head impulse test’s sensitivity and specificity for the anterior and posterior canals on a bedside scenario, taking the classic caloric test as gold standard. Material and method: Prospective test-assessment study. A head impulse test for every semicircular canal was performed on patients with indication of vestibular study with caloric test. Results: 118 patients were evaluated, where 49,2% presente an abnormal caloric test. The head impulse test’s sensitivity for the posterior canal canal was 13,1% (3,2% for the anterior canal). The test’s specificity was 100% for both vertical canals. On the horizontal plane, sensitivity reached 63,9%, while specificity was 100%. Discussion: The head impulse test for vertical (anterior and posterior) canal on a bedside scenario is highly specific but poorly sensitive, thus having a relatively low clinical utility. On the contrary the test for the horizontal canal remains a quick and simple tool, with acceptable sensitivy and great sensitivity for assessing vestibular function loss.