Genetic implications of gender differences in the prevalence of spontaneous otoacoustic emissions

Spontaneous otoacoustic emissions (SOAEs), which occur in about 40% of normal-hearing humans, do not have a firm explanation in auditory theory nor are their distributional properties well understood. To enhance our understanding of SOAEs, we have pooled data from three reports (Hammel, 1983; Strickland, Burns, & Tubis, 1985; Zurek, 1981) to assemble a large enough sample to assess the relevant hypotheses about the effects of ear and gender on their presence. The results, based on loglinear analyses of the pooled sample of 131 normal-hearing subjects, indicated that (a) the prevalence of SOAEs for female subjects [P(S/F) = .533] was significantly higher than that for male subjects [P(S/M) = .268]; (b) the percentage of right ears with SOAEs (36.6%) was significantly greater than that of left ears (25.2%); and (c) right and left ears were not independent with respect to the presence of SOAEs. These results can be explained by assuming that the (a) tendency to exhibit emissions is inherited, perhaps as a sex-linked trait and (b) ears are asymmetric with respect to the anatomical anomalies of the apical portion of the organ of Corti that may precipitate SOAEs.