Test-Retest Reliability of the Binaural Interaction Component of the Auditory Brainstem Response.
Alexander T Ferber, Victor Benichoux, Daniel J Tollin
PMID 27232069WHAT IT FOUND
In guinea pigs, raw binaural auditory brainstem amplitudes varied across sessions.
Dividing the binaural amplitude by the monaural response strength let 20% curve changes be detected; raw amplitudes needed more than 50% reduction or a two-fold increase.
Key findings
01Across recording sessions in guinea pigs, raw BIC DN1 peak amplitude varied by about 0.08 μV on average, while the maximal amplitude was about 0.8 μV.
02RMS normalization allowed a 20% change in the BIC-to-ITD curve to be distinguished, while raw data required more than 50% reduction or a two-fold increase.
03After normalization, a lateral shift of 250 μs could be detected, whereas raw data could not distinguish shifts even as large as 1 or 2 ms.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study used eight anesthetized guinea pigs, not people, so it does not show how the method performs in patients. Only 29 BIC recordings were analysed, and the animals were normal-hearing, so the range of human binaural hearing problems is not represented. Abnormality detection was tested by applying simulated changes to animal recordings, not by measuring people with suspected binaural hearing disorders. The authors did not set false-positive rates or diagnostic thresholds; they state the comparison is not a proper test per se.
Declared interests
The authors declared no conflicts of interest.
The easy way to misread this
Do not read this as validation of a clinical BIC test for people. The finding comes from repeated recordings in eight guinea pigs and from simulated curve changes, not from patients or a diagnostic accuracy study.