Normative Ranges for Auditory Brainstem Response Wave I Amplitude: A Potential Diagnostic Indicator of Cochlear Deafferentation.

Summary

Established normative ranges for auditory brainstem response (ABR) Wave I amplitude, a marker sensitive to cochlear synaptopathy, in 169 low-risk adults with normal audiograms, minimal noise exposure, and no auditory complaints. Comparing 91 high-risk military veterans (normal audiograms but at least one auditory complaint) against these ranges, sex-adjusted ABR normative ranges (without further adjustment for outer hair cell function) distinguished the two groups, with 51% of the high-risk sample falling below normative amplitude at 8 kHz.

Key findings

• Sex-specific ABR Wave I amplitude normative ranges, from 169 low-risk adults, can flag likely cochlear deafferentation in individual patients with normal audiograms.
• 51% of a high-risk veteran sample (normal audiograms, auditory complaints) fell below the normative range at 8 kHz.
• Adjusting further for outer hair cell function (via DPOAE) did not improve, and could complicate, the normative ranges.