What Do Vestibular Tests Reveal in Vestibular Migraine?

INTRODUCTION: Vestibular migraine (VM) is a common cause of recurrent vertigo, yet no single vestibular test is specific to it. This study aimed to evaluate videonystagmography (VNG), caloric test, and video head impulse test (vHIT) findings in VM patients and to examine the relationships between these tests. METHODS: This retrospective study included 193 patients with definite VM diagnosed per Bárány Society/International Headache Society criteria (January 2016-May 2026). All patients underwent VNG, caloric testing, and vHIT on the same day, in all cases outside an acute attack. Oculomotor, positional, and caloric findings were compared with vHIT results. Demographic characteristics, audiometric findings and vascular comorbidities were also recorded. RESULTS: vHIT was normal in 66.3% of patients and abnormal in 33.7%. Mean VOR gain was 0.97 ± 0.19 overall and 0.86 ± 0.14 in patients with an abnormal vHIT. Oculomotor abnormalities were detected in 38.3%, positional test positivity in 20.7%, and caloric test abnormalities in 40.9% (mean canal paresis 42.9 ± 16.7% in affected patients). No significant associations were found between vHIT and oculomotor (p=0.262), positional (p=0.255), or caloric test results (p=0.974). A caloric-vHIT dissociation, defined as an abnormal caloric response with a normal vHIT, was present in 53 patients (27.5%). CONCLUSION: Vestibular tests reveal a heterogeneous pattern of dysfunction in VM with no significant categorical inter-test associations. The caloric-vHIT dissociation may reflect frequency-dependent differences in vestibular function, although at a rate well below that reported for Ménière's disease, so that it supports rather than replaces clinical differentiation. These findings suggest that each test captures distinct aspects of vestibular function and should be used as complementary tools in the multimodal evaluation of vestibular migraine.