INTERRELATIONS BETWEEN PSYCHOACOUSTICAL TUNING CURVES AND SPONTANEOUSAND EVOKED OTOACOUSTIC EMISSIONS

With the hypothesis that cochlear active mechanisms are the origin of otoacoustic emissions (OAEs) and of the high frequency selectivity exh ibited by the ear, psychoacoustical tuning curves (PTCs), transiently evoked otoacoustic emissions (TEOAEs), and spontaneous otoacoustic emi ssions (SOAEs) have been examined in 50 normal hearing subjects. Using a clinical simplified method, PTCs were successively assessed at thre e frequencies-1, 2 and 4 kHz-in each subject. The results showed the e xistence of significant differences in the quality of tuning (Q10dB) o f the PTCs between, first, subjects having SOAEs and subjects having n o SOAEs (Student's t-test; p < 0.05; df = 35) and, second, subjects ha ving large TEOAEs and subjects having small TEOAEs (Student's t-test; p < 0.05; df = 14). Nevertheless, these significant differences did no t appear for all the frequencies studied: the frequency selective rela tionship between PTCs and OAEs mainly involved the 2 kHz zone. Such re sults are discussed according to the specificities of the clinical met hod used for PTC measurement as well as to the spectral characteristic s of OAEs.