Cochlear nerve fiber populations in 25 patients with profound deafness due to Menière's disease or sudden deafness.

Surgical biopsy specimens of the cochlear nerve from 19 patients with Menière's disease and six patients with sudden deafness were studied. The total number of myelinated nerve fibres in the transverse fascicular area of each nerve were counted and the results were correlated with the clinical and preoperative audiological data. The total number of cochlear neurons in patients with Menière's disease ranged from 5,760 to 27,722 and in patients with sudden deafness from 8,500 to 22,714. The long duration of the disease or absent speech discrimination appeared not to be connected with lower numbers of neurons than preserved speech discrimination or short history of the disease.