Temporal bone studies of the human peripheral vestibular system 2. Normative Scarpa's ganglion cell data

Scarpa's ganglion cell counts were performed in 106 serially sectioned, nor mal human temporal bones from 75 individuals. Of these 106 bones, 15 were f rom neonates less than 30 days old, 14 were from infants between the ages o f 1 and 12 months, and the remainder were distributed throughout each decad e of life, with sample sizes ranging from 4 to 10 per decade. All temporal bones had to meet 2 criteria: no symptoms or signs of inner ear disease exc ept for presbycusis in the medical case history and no abnormality in the i nner ear on light microscopy. The total ganglion cell counts declined signi ficantly with age at an average rate of 57 cells per year. The age-related decline was significantly greater in the superior division than in the infe rior division. There was also a significant sex effect, independent of age: for any age, the count in men averaged 1,526 cells higher than in women. T here was no significant interaural difference. Mathematical models were dev eloped to compute the mean and 95% prediction intervals for Scarpa's gangli on cell counts in terms of age and sex parameters. The counts and models wi ll serve as a normative database against which to compare counts made in te mporal bones from subjects with known vestibular disorders.