Differentiating cerebellopontine angle meningioma from schwannoma using caloric testing and vestibular-evoked myogenic potentials

ObjectiveThis study utilized audiometry, and caloric, ocular vestibular-evoked myogenic potential (oVEMP) and cervical VEMP (cVEMP) tests to differentiate between cerebellopontine angle (CPA) meningioma and schwannoma.Patients and methodsEleven CPA meningioma patients with mean tumor size 2.8 ± 1.4 cm and another 11 CPA schwannoma patients with mean tumor size 2.7 ± 1.0 cm were enrolled in this study. All patients underwent a battery of audiovestibular function tests.ResultsThe two groups did not differ significantly in terms of clinical manifestation. The abnormal percentage of caloric test in the meningioma group was 36%, compared to 91% in the schwannoma group, and thus both groups differed significantly. However, such difference was not observed between the two groups regardless of mean hearing level, oVEMP test and cVEMP test.ConclusionCombined caloric with oVEMP test results may help differentiate a CPA tumor. Correlation between the caloric and oVEMP test results in a CPA tumor indicates a schwannoma nature, while dissociation between the caloric and oVEMP test results depicts a meningioma character.