Abstract

Background: The objective of the study was to evaluate hearing threshold errors induced by the use of a new acoustical protocol (Cochlea-Scan).
Material/Methods: Thirty-five normally hearing and 30 hearing-impaired adults were used in the study. Hearing threshold levels were assessed by pure tone audiometry (PTA) and the Cochlea-Scan (Fischer-Zoth/Natus) DPOAE protocols.
Results: In the normal-hearing group, the mean difference in hearing levels at 2.0, 3.0, and 4.0 kHz was below 8 dB HL. At 1.5 kHz the mean difference was around 9 dB HL, while at 6.0 kHz the behavioral threshold was overestimated by 2 dB HL. Although linear regression models suggested a significant relationship between the behavioral and the Cochlea-Scan data in all the tested frequencies, the low R2 values in each model suggest an unexplained variability in the data. For the hearing-impaired group the mean difference in hearing levels at 1.5 and 2.0 kHz was below 5 dB, while at 4.0 kHz the behavioral threshold was overestimated by 7 dB. In this group the observed relationships were stronger (larger R[sup]2[/sup] values) than in the normal group, and the most significant relationships were observed at 2.0, 4.0, and 6.0 kHz (with descending R[sup]2[/sup] values).
Conclusions: The data from this pilot study indicate that Cochlea-Scan assessment is possible and accurate in both normal-hearing and in hearing-impaired subjects. The margin of assessment in the hearing-impaired group was found to be closer to a PTA value of 40 dB and not 50 dB HL as previously suggested.

Keywords: Cochlea - physiology, Auditory Threshold, Hearing - physiology, Hearing Tests - methods, Pilot Projects