2009 年 68 巻 1 号 p. 45-50
This study aimed to investigate vestibular evoked myogenic potential (VEMP) latencies in patients with acoustic neuromas (ANs), and to clarify the change in the 3 parameters: origin nerve, localization, and tumor size. The VEMPs of 119 patients with ANs confirmed surgically were recorded. We used the peak latencies of the first positive-negative peak of the VEMP, P13-N23, for the evaluation. VEMPs were absent in 49 (41%) of patients with ANs. Both patients with superior and inferior neuromas had a significantly prolonged p13 and n23. Patients with ANs of 11∼20mm in size had a significantly prolonged p13. Patients with ANs present in both the internal auditory meatus and the cerebropontine (CP) angle had a significantly prolonged p13 and n23. These results suggest that it is impossible to predict the origin nerve of a tumor from the results of the VEMP. We hypothesized that the latency prolongation is caused not only by the tumor size but also by the tumor localization.