Normal ABR Threshold
Normal auditory brainstem response (ABR) thresholds in adults typically range from 0-20 dB nHL (normalized hearing level), with most studies showing mean thresholds between 4-10 dB nHL for click stimuli.
Understanding ABR Threshold Normative Values
The provided guidelines focus primarily on pure tone audiometry as the gold standard for hearing assessment 1, 2, but research evidence establishes clear normative ABR values:
Click-Evoked ABR Thresholds
- Adults: Mean ABR threshold to air-conducted clicks is approximately 3.75 dB nHL (equivalent to 40.75 dB peak SPL) 3
- Neonates: Similar threshold of 3.75 dB nHL for air-conducted clicks 3
- Clinical correlation: ABR click thresholds typically fall within 5-10 dB of psychophysical thresholds for similar stimuli 4
Frequency-Specific ABR Thresholds
When using tone pips with appropriate masking:
- Thresholds range from 28.6 to 36.6 dB peak-equivalent SPL, equivalent to 4.4-8.8 dB nHL across frequencies from 500 Hz to 4000 Hz 5
- 1000 Hz specific: Binaural stimulation yields approximately 12 dB nHL, while monaural stimulation yields 18 dB nHL 6
Clinical Application Context
Important caveat: While the guidelines mention ABR as a screening tool for vestibular schwannoma in sudden sensorineural hearing loss 2, they emphasize that pure tone audiometry remains the gold standard for comprehensive hearing assessment 1. ABR is described as "less sensitive" than MRI for tumor screening but useful when MRI is contraindicated 2.
Key Clinical Thresholds
- Normal hearing: ABR thresholds ≤20 dB nHL
- Clinical significance: ABR thresholds within 10 dB of pure-tone average in pediatric populations with hearing loss ranging from mild to profound 4
- Severe hearing loss threshold: ABR thresholds ≥60 dB nHL indicate severe dysfunction and show poor correlation with speech perception 7
Practical Considerations
Sex differences matter: Recent evidence shows biological sex is a significant predictor of Wave V latency, independent of hearing thresholds 8, 9. Sex-specific normative ranges should be used when available.
Extended high-frequency sensitivity: While standard audiometry may appear normal (≤20 dB HL from 0.125-8 kHz), extended high-frequency thresholds (9-20 kHz) independently predict Wave I amplitude, suggesting subclinical cochlear deficits 8.
Test-retest reliability: Standard diagnostic variability in adults typically fluctuates by ±5 dB across frequencies 1, which should be considered when interpreting borderline results.