Author: David R.
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
TO GO TO HAPLAB
DOWNLOADS PAGE (includes info/papers related to ABR, ASSR, and
How do I determine
(i) which ear to test first, and (ii) starting intensity for
In most cases (i.e.,
adults), you will have a behavioural audiogram:
- Test the worse ear first
(based on 2-4 kHz behavioural oure-tone audiogram) [You do this because
(i) this is the side where a problem would typically be expected, and
(ii) this will determine the stimulus intensity for testing each ear
should you need to assess interaural latency asymmetries (remember:
IALD V requires the same acoustic intensity to be presented for each
- Start at 80 dBnHL or at 20 dB
"SL", whichever is higher -- that is, about 20dB above the
2-4kHz behavioural thresholds. If thresholds are 60dBHL or better,
start ABR at 80 dBnHL. If thresholds are 70dBHL, then clicks at 90dBnHL
are an appropriate starting intensity. Most equipment is limited to 95
or 100 dBnHL -- you likely do not want to go higher and might limit
your maximum to 95dBnHL.
Can/should one use the
contralateral recording to help identify/measure the ipsilateral wave V?
No. I disagree that one can use
"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.]
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).
(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]
© David R. Stapells, 2003, 2004