Analyses of notches in audioscan and DPOAEs in subjects with normal hearing

In this study, the parameters of notches in the Audioscan have been compared with the distortion product otoacoustic emission (DPOAE) findings in 100 subjects with normal hearing, including 55 normal controls and 45 patients with King Kopetzky syndrome. Of those, 35 subjects had Audioscan notches (11 controls and 24 patients), 96 per cent (53 out of 55 notches) of which were associated with notches in DPOAEs. Analyses showed that the notch centre frequencies obtained in the Audioscan test correlated significantly with those of the notches found on the distortion product audiogram (DP-gram). In addition, the width of notches of the two procedures was also significantly correlated. It is likely, therefore, that such notches on Audioscan and DPOAE testing reflect localized areas of impaired cochlear function.