Vestibular Evoked Myogenic Potential in Vestibular Migraine: A Systematic Review of Diagnostic Utility

Background/Objectives: Vestibular migraine (VM) is one of the most prevalent causes of episodic vertigo, yet it remains underdiagnosed due to overlapping features with other vestibular disorders and the absence of definitive diagnostic tests. Vestibular evoked myogenic potentials (VEMPs) assess otolith and vestibular nerve function and may help identify pathophysiological mechanisms in VM. This systematic review aimed to evaluate the usefulness of VEMP in understanding VM, synthesize existing findings, and explore its clinical implications. Method: A systematic search was performed in PubMed, ProQuest, Scopus, Web of Science, and EMBASE up to 2025 following PRISMA guidelines. Studies were included if they assessed cVEMP and/or oVEMP in patients diagnosed with VM using established clinical criteria. Data extraction and quality assessment were conducted independently by three reviewers using Cochrane and Joanna Briggs Institute tools. A total of 2578 titles and abstracts were screened, and 28 studies met the inclusion criteria. Results: Across 28 studies, 23 reported VEMP abnormalities in VM. The most frequent findings were reduced amplitudes and increased asymmetry ratios compared to healthy controls, indicating potential otolithic dysfunction. Latency prolongations were less consistently reported. Differences between cVEMP and oVEMP findings in individuals with VM suggested variable involvement of saccular and utricular pathways, with oVEMP abnormalities appearing more prominent. Conclusions: VEMP testing reveals subtle vestibular dysfunction in VM, primarily reflected in reduced amplitude and altered asymmetry ratios. However, the association between VEMP abnormality and VM is inconclusive, specifically due to heterogeneity among the included studies. Although findings support its potential as a diagnostic adjunct, methodological variability (including variability in patient recruitment) underscores the need for standardized VEMP protocols to enhance diagnostic accuracy and comparability across studies.