Transient evoked otoacoustic emissions in superior canal dehiscence syndrome.

Superior semicircular canal dehiscence syndrome (SCDS) is a clinical disorder that is characterized by vertigo and oscillopsia induced by loud sounds. Transient evoked otoacoustic emissions (TEOAEs) allow to noninvasively check the integrity of the cochlea. The present study aimed at identifying cochlear stress as the result of micro alterations of the cochlear functionality due to anatomic anomaly. 11 SCDS and 10 normal individuals as control group were submitted to history taking, otological examination, basic audiologic evaluation and TEOAEs analysis using the standard wideband protocol and moving time window analysis. Although TEOAEs test results showed no statistically significant difference using the standard protocol, off-line analysis of the waveforms' "effective duration" was statistically significantly shortened (p < 0.0001) when compared to normal ears. In conclusion, dehiscence of bone overlying the superior canal has been shown to have effects on inner ear function in terms of a third mobile window theory, thus altering pressure across cochlear partition with decrease in inner ear impedance.