Author: David R. Stapells
Hamber Professor of Clinical Audiology  & Director, School of Audiology & Speech Sciences
University of British Columbia, Vancouver, B.C.  Canada
      © David R. Stapells, 2003, 2004, 2005, 2006


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How do I determine (i) which ear to test first, and (ii) starting intensity for retrocochlear assessments?
In most cases (i.e., adults), you will have a behavioural audiogram:

Can/should one use the contralateral recording to help identify/measure the ipsilateral wave V?

No. I disagree that one can use contralateral "wave V" to accurately identify or measure ipsilateral wave V. Although many clinicians persist in this practice, there is no evidence to support it! Indeed, by definition, the contralateral "view" results in a waveform that is different in latency, amplitude, and often morphology -- being different, it cannot provide a measure of ipsi wave V. This pdf file with four examples of how contra wave V can mislead you.

Infant responses: the contralateral recording in infants is even more different. Several papers in the 80s and 90s [e.g., Stapells, D.R. & Mosseri, M. Maturation of the contralaterally recorded auditory brainstem response. Ear and Hearing, 1991, 12, 167-173.]  demonstrated the different infant click-ABR contralateral response. One thing is clear, the normal infant contra response is much smaller and later than the ipsi response, and may even be absent (this is not abnormal).

Stapells (Revised, September 2005): Response signal-to-noise measures (RN, SNR, CCR) available on the IHS Smart-EP: Preliminary guidelines

The Intelligent Hearing Systems "Smart-EP" clinical AEP system has some interesting and useful SNR measures -- especially the residual noise (RN) measure. (Note: most clinical AEP systems have "CCR": correlation between replications.) This pdf file has some preliminary guidelines for their use. [click here]

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