Yi-Feng Hu1, Po-Wen Cheng, Yi-Ho Young. 1. Department of Otolaryngology, Far Eastern Memorial Hospital, National Taiwan University Hospital, Taipei, Taiwan.
Abstract
CONCLUSION: Abnormal caloric and vestibular evoked myogenic potential (VEMP) responses are frequently encountered with a large cerebellopontine angle (CPA) schwannoma, while normal caloric responses and abnormal VEMPs are noted with a large CPA meningioma. This difference may possibly exist because schwannoma causes vestibular deficits via parenchymal involvement, while vestibular deficits in the meningioma are mostly due to compression neuropathy. OBJECTIVES: This study aimed to compare the tumor characteristics in relation to vestibular function, i.e. caloric and VEMP responses, between large-sized (>2.5 cm) meningioma and schwannoma in the CPA. PATIENTS AND METHODS: Five patients with large CPA meningioma and nine patients with large CPA schwannoma were enrolled in this study. Each patient underwent a battery of tests including audiometry, caloric test, VEMP test, and MRI study. RESULTS: The meningioma group showed 20% caloric abnormality and 75% VEMP abnormality, while the schwannoma group revealed 100% caloric and 100% VEMP abnormalities. A significant difference existed in relation to caloric abnormality between the two groups, but not in relation to VEMP abnormality.
CONCLUSION: Abnormal caloric and vestibular evoked myogenic potential (VEMP) responses are frequently encountered with a large cerebellopontine angle (CPA) schwannoma, while normal caloric responses and abnormal VEMPs are noted with a large CPA meningioma. This difference may possibly exist because schwannoma causes vestibular deficits via parenchymal involvement, while vestibular deficits in the meningioma are mostly due to compression neuropathy. OBJECTIVES: This study aimed to compare the tumor characteristics in relation to vestibular function, i.e. caloric and VEMP responses, between large-sized (>2.5 cm) meningioma and schwannoma in the CPA. PATIENTS AND METHODS: Five patients with large CPA meningioma and nine patients with large CPA schwannoma were enrolled in this study. Each patient underwent a battery of tests including audiometry, caloric test, VEMP test, and MRI study. RESULTS: The meningioma group showed 20% caloric abnormality and 75% VEMP abnormality, while the schwannoma group revealed 100% caloric and 100% VEMP abnormalities. A significant difference existed in relation to caloric abnormality between the two groups, but not in relation to VEMP abnormality.