Ann F. Russell
Robert C. Bilger
Dept. of Speech and Hear. Sci., Univ. of Illinois at Urbana--Champaign, 901 South Sixth St., Champaign, IL 61820
Because spontaneous otoacoustic emissions (SOEs) are correlated with sex and because sex is determined genetically, Bilger et al. (1990) hypothesized that SOEs are inherited. A twin study was planned to pursue this idea. A total of 60 sets of twins [15 sets of monozygotic (MZ) females, 15 sets of MZ males, 15 sets of dizygotic (DZ) females, and 15 sets of DZ males] were measured for SOEs using an off-line procedure to determine the broad-sense heritability (H) of these emissions. Their ages ranged from 5--40 years. All subjects had essentially normal hearing. Zygosity was determined by means of a zygosity questionnaire (Lykken et al., 1988). Results indicate that SOEs are a highly heritable trait (H=1.0). Further, the SOE profiles of MZ twins were strikingly similar, whereas the profiles for DZ twins were not. [Work supported by DC00174.]