Cervical vestibular evoked myogenic potential asymmetry may contribute to differentiation between vestibular migraine and Meniere's disease

Vestibular migraine (VM) and Meniere’s disease (MD) are both characterized by recurrent, episodic vertigo. In patients with recurrent vertigo, it is sometimes difficult to differentiate between VM and MD if the vertigo is not associated with migrainous headache or hearing loss. In the present study, to differentiate between VM and MD, we analyzed the results of ex-aminations of the peripheral vestibular system; the medical records of 23 patients, including 12 with definite VM and 11 with definite MD, were reviewed retrospectively, with a focus on the results of the caloric test and cervical vestibular evoked myogenic potential (cVEMP) testing. The caloric test revealed no statistically significant difference in the incidence of canal pa-resis between patients with VM and MD; however, the asymmetry ratio (AR) of cVEMP ob-tained using 500 ― Hz short-tone burst stimuli was significantly higher in patients with MD than in patients with VM (p ＝ 0.04, Fisher’s exact probability test). The tuning properties of short-tone burst stimuli of 500 Hz and 1,000 Hz during cVEMP testing tended to shift to a higher frequency in the affected ears of patients with MD as compared with that in the ears of patients with VM, although the difference was not significant (p ＝ 0.12, Welch’s t-test). These differ-ences are consistent with the findings of a previously conducted pathological investigation of the temporal bone in patients with MD, which suggested that severe endolymphatic hydrops is observed most frequently in the saccule of the inner ear. The present study findings indicate that evaluation of dysfunction of the saccule, especially the AR in cVEMP may be helpful in the differential diagnosis between VM and MD.