D-0120578-C – 2019/11
Eclipse – Instructions for Use - US
Page 56
3.12.3 Interpretation of the ALR result
The ALR/ACR latency ranges from 50-300ms and amplitude sizes ranges from 0-20uV. A typical ALR threshold
recording here using Tone Burst 2kHz for threshold evaluation
.
Typically the ALR threshold recording is started at 60 dB nHL and a decision is then made to increase or
decrease the stimulus intensity by 20 dB. 5 or 10 dB steps are typically used when close to threshold. The
ALR threshold at 25 dB nHL at 2kHz found here would be within the range of normal hearing. Applying a
typical correction factor would estimate the behavioral audiogram threshold to be 18.5 dBHL at 2 kHz.
Lowest level response >5uV: interpolate
Lowest level response <5uV: is threshold
3.12.4 Electrophysiological threshold estimation and infant hearing instrument
fitting
ALR threshold behavioral correction factors to estimated hearing thresholds to be used for hearing
instrument fitting.
Example of correction from dBnHL to dBeHL.
nHL
(dB)*
hearing level eHL
*Reference http://www.corticalera.com/research.html
“Results: The mean error in the N1-P2 threshold estimate was 6.5 dB, with no
significant effect of frequency. After correcting for this bias, 94% of individual
threshold estimates were within 15 dB of the behavioral threshold and 80%
were within 10 dB. Establishing the 6 threshold estimates (3 frequencies, 2
ears) took on average 20.6 minutes.”
Further information about ALR recordings can be obtained from Eclipse Additional Information Manual.
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