Vestibular function analysis in patients with unilateral Ménière's disease

Ménière's disease (MD) is characterized by episodic vertigo, fluctuating hearing loss, tinnitus, and aural fullness. As vertigo is a cardinal symptom, evaluating vestibular function is essential for disease assessment. However, the relationship between vestibular function and the degree or location of endolymphatic hydrops (EH), as well as the stages of Ménière's disease (MD), remains unclear.

Patients diagnosed with definite Unilateral Ménière's disease (UMD) underwent a comprehensive vestibular function evaluation, including cervical and ocular vestibular evoked myogenic potentials (cVEMP, oVEMP), video head impulse test (vHIT), caloric test, and sensory organization test (SOT). Inner ear gadolinium-enhanced MRI (Gd-MRI) was performed to the assessment of endolymphatic hydrops(EH).Vestibular function parameters were compared across MD stages and EH categories. Fisher's exact test was used for statistical analysis.

cVEMP and oVEMP non-response rates increased significantly with advancing MD stage and were significantly higher in Stages III-IV compared to Stages I-II. vHIT abnormalities were predominantly observed in Stage IV. Caloric test abnormalities were significantly lower in Stage I but showed no significant differences among later stages(II, III, IV). No significant differences were found in SOT-derived balance function (BF) or vestibular function (VF) across MD stages. Furthermore, there was no linear correlation between vestibular test results and overall endolymphatic hydrops level(EHL). Similarly, vestibular dysfunction rates did not differ significantly among patients with isolated cochlear, isolated vestibular, or both cochlear and vestibular EH.

Vestibular function changes in UMD are stage-dependent, with early involvement of otolithic and low-frequency semicircular canal function, while high-frequency canal dysfunction appears later. However, these changes do not consistently correlate with EH severity or anatomical distribution. Central compensation and functional-structural mismatch may underlie these discrepancies. Multimodal and longitudinal approaches are needed to better understand vestibular pathophysiology in MD.