Ultrastructural analysis of the vestibular nerve in Ménièreʹs disease

Numerical analysis of the vestibular nerve in Ménièreʹs disease was performed. Vestibular nerve specimens were obtained from three patients with classical clinical findings of Ménièreʹs disease during retrosigmoid vestibular neurectomy. For each patient, an ultrathin section, including an entire cross-section of the nerve specimen, was examined. Fiber counts of nerve specimens with definite pathologic findings were compared with caloric testing results. A significant correlation was found between reduced vestibular response and the incidence of abnormal nerve fibers and also the density of the abnormal nerve fibers. However, the number of nerve fibers with pathologic findings was small. Results of the present study demonstrate no general degeneration of nerve fibers caused by the disease process of Ménièreʹs disease.