Spontaneous otoacoustic emissions in schoolchildren.

OBJECTIVE

Spontaneous otoacoustic emissions (SOAEs) are one of the least studied types of otoacoustic emissions (OAEs). The purpose of this study was twofold: first, to determine the prevalence of SOAEs in schoolchildren, and second to test whether there was dependence between the presence or absence of SOAEs in a subject and the corresponding level of their transiently evoked OAEs (TEOAEs).

METHODS

Measurements were made on a group of normally hearing children of age 7-13 years. A technique which detects synchronized SOAEs (SSOAEs) was used in which the response to repetitive clicks (12.5/s) was analyzed in the 60-80 ms time window following each click. The matching pursuit method was used to detect SSOAEs components above the noise in this window. For comparison, TEOAEs evoked by clicks (40/s) were obtained using the standard nonlinear protocol (20 ms time window).

RESULTS

The prevalence of SOAEs was 37%, and higher in females and right ears. There was an average of 2.3 SOAEs per emitting ear. TEOAE levels were higher for ears that had SOAEs and were lower for ears that did not have any SOAEs.

CONCLUSION

Although not all normal human have SOAEs, they appear to reflect an important aspect of cochlear function. Their presence is strongly related to elevated levels of TEOAEs which are routinely used in audiological tests.