p-ISSN 2083-389x   e-ISSN 2084-3127



Edward C. Killan, Ruth E. Brooke, Alexandra Farrell, Jessica Merrett

(LICAMM, University of Leeds, Leeds, United Kingdom)

JHS 2017; 7(2): 27-36

DOI: 10.17430/902926

Published: 2017-05-15

BACKGROUND: Contralateral suppression of click-evoked otoacoustic emissions (CEOAEs) is a potentially useful clinical tool. Recent studies have provided descriptions of the reliability of this measure. In terms of their clinical relevance, the studies were limited as they utilised custom-built measurement systems or were conducted by a single tester over a short time. Further, previous studies generally reported only group data. The present study addresses these limitations by reporting individual and group data collected by two testers, using standard clinical equipment over longer time-frames.
MATERIAL AND METHODS: Contralateral suppression of CEOAEs was recorded from 12 ears using the ILO 292 system. Clicks and contralateral broadband noise (BBN) were presented at 60 dB p.e. SPL and 65 dB SPL respectively. Global and best half-octave band suppression values (in dB) were measured on four separate occasions by two testers spanning an average period of 35.5 days. Reliability was assessed via the intraclass correlation coefficient (ICC) and the standard error of measurement (SEm). Multilevel regression analysis was used to explore potential causes of variation in suppression.
RESULTS: Global suppression reliability was shown to be worse than previous reports, with only fair to good reliability observed. ICC and SEm values were 0.57 and 0.47 dB respectively. Corresponding values for best half-octave band suppression were 0.49 and 0.64 dB. Further analysis revealed no significant effect on contralateral suppression for a range of variables tested. Substantial variation (up to 2 dB) in contralateral suppression between test sessions was seen for individual subjects.
CONCLUSIONS: Findings suggest that contralateral suppression of CEOAEs, measured by separate testers using standard clinical equipment, is not reliable over long time periods.

Keywords: Cochlea, Hearing Tests, Reproducibility of Results