Unbiased stereological quantification of neurons in the human spiral ganglion

We applied an unbiased stereological technique, the optical fractionator, o n five human archival temporal bone specimens to estimate the total number of spiral ganglion neurons. Available archival human temporal bone specimen has been serially sectioned at 20 mum and every tenth section was stained. All the stained sections passing through the spiral ganglion were used for the analysis. From each section sampled, the counting areas were systemati cally randomly sampled within the sectional area of the spiral ganglion. Th e neurons within the counting areas sampled were counted with the optical d isector technique. The total number of the human spiral ganglion neurons wa s estimated by multiplying the number of neurons counted by the reciprocal of the aggregate sampling fraction. We found an average of 41 700 neurons w ith a coefficient of variation of 0.14, which is a significant departure fr om the previously published data obtained with the assumption-based methods . The mean coefficient of error for the stereological estimates of the tota l number of human spiral ganglion neurons was 0.078. The present report pre sents unbiased stereological sampling and counting strategies for the futur e quantitative studies on the spiral ganglion neurons. The result of the pr esent study provides the fi rst unbiased baseline value of the human spiral ganglion neurons. (C) 2001 Elsevier Science Ireland Ltd. All rights reserv ed.