Intertest Reliability in Non-invasive Electrocochleography

Intertest reliability of action potential (AP) and summating potential (SP) parameters in non-invasive electrocochleography (ECochG) was studied in 4 normal ears and 7 hearing-impaired ears with stable audiograms. The interval between test and retest was 10 days to 2 years and 5 months. Intertest differences in AP response threshold and -SP detection threshold were within 10 dB. N1 amplitude, N1 latency, -SP amplitude, and -SP/AP ratio had excellent correlations between test and retest. N1 latency had a better intertest reliability than N1 amplitude. Waveform had almost the same shape in retest as in test. The intertest differences in AP and SP parameters were examined. On the basis of these data values for the criteria of significant change in test and retest in non-invasive ECochG are presented. The non-invasive ECochG is particularly suitable for monitoring both progressive and fluctuant hearing loss.