Intrasubject Test-Retest Reliability in Tympanic Electrocochleography

To help establish the clinical reliability of electrocochleography (ECochG), we defined normal limits of variability for the summating potential (SP)/auditory nerve action potential (AP) amplitude ratio across multiple recording sessions from the same subjects . ECochG was recorded bilaterally from the tympanic membranes of 10 normal-hearing adults at six sessions separated by 2to 14-day intervals. The measures of variability examined included overall range, overall average standard deviation, and mean average difference . Examiner improvement over the six sessions also was examined . Results from the variability data indicate that the reliability of tympanic ECochG can be determined by how many of the measures of variability fall within the normal limits established in this study. No significant examiner improvement was seen between the first three and last three recording sessions .