What is the normal auditory‑brainstem‑response (ABR) threshold?

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Last updated: October 10, 2026 • View editorial policy

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Normal ABR Threshold

Normal auditory brainstem response (ABR) thresholds are approximately 0-20 dB nHL (normalized hearing level) for click stimuli in adults and children, with frequency-specific thresholds varying by test frequency.

Age-Specific Normal Values

Neonates and Infants

  • Click stimuli: Mean ABR threshold of 3.75 dB nHL (40.75 peak SPL) for air-conducted clicks 1
  • Bone-conducted clicks: Mean threshold of 1.25 dB nHL in neonates 1
  • Frequency-specific thresholds (using tone bursts in notched noise) 2:
    • 500 Hz: 23.6 dB nHL
    • 2000 Hz: 12.9 dB nHL
    • 4000 Hz: 12.6 dB nHL
  • Clinical significance: 92-100% of infants with normal hearing show ABR responses to 30 dB nHL tones 2

Adults

  • Click stimuli: Mean ABR threshold of 3.75 dB nHL for air-conducted clicks 1
  • Bone-conducted clicks: Mean threshold of 18.75 dB nHL (significantly higher than neonates) 1
  • High-frequency thresholds: ABR thresholds at 6 and 8 kHz average 5-6 dB above behavioral thresholds 3

Clinical Interpretation Framework

Threshold Correlation with Behavioral Hearing

The relationship between ABR thresholds (measured in dB nHL) and behavioral pure-tone thresholds (measured in dB HL) shows predictable patterns 2:

  • 500 Hz: ABR threshold averages 8.6 dB higher than behavioral threshold
  • 2000 Hz: ABR threshold averages 0.4 dB lower than behavioral threshold
  • 4000 Hz: ABR threshold averages 4.3 dB lower than behavioral threshold

98% of ABR thresholds fall within 30 dB of behavioral thresholds, and 93% fall within 20 dB 2. This makes ABR highly reliable for estimating hearing sensitivity.

Screening vs. Diagnostic Criteria

According to AAP guidelines 4:

  • Air-conduction thresholds >20 dB at any frequency indicate possible hearing loss requiring referral to a pediatric audiologist
  • ABR is not a true test of hearing but rather tests auditory pathway structural integrity
  • Behavioral audiometry remains the gold standard when obtainable

Important Clinical Caveats

Binaural vs. Monaural Testing

Binaural ABR thresholds are approximately 5.5 dB lower than monaural thresholds 5. This difference is statistically significant and should be considered when interpreting results.

Test Specificity

For high-frequency testing (6-8 kHz), test specificity is 100%: no participants with behavioral thresholds ≤20 dB HL had ABR thresholds >25 dB nHL 3. This means ABR accurately identifies normal hearing sensitivity with no false positives.

Limitations in Severe Hearing Loss

In patients with severe hearing loss (ABR thresholds ≥60 dB nHL or speech perception <50%), ABR thresholds do not correlate with functional hearing 6. This limits ABR's clinical validity for assessing cochlear implant candidacy or functional auditory performance in this population.

Age-Related Differences

The dissimilarity in bone conduction thresholds between neonates (1.25 dB nHL) and adults (18.75 dB nHL) likely reflects differences in signal delivery efficiency to the cochlea 1. This must be considered when comparing results across age groups.

Practical Application

When evaluating ABR results:

  • Thresholds 0-20 dB nHL: Normal hearing range
  • Thresholds 20-30 dB nHL: Borderline; correlate with behavioral testing
  • Thresholds >30 dB nHL: Likely hearing loss; refer for comprehensive audiological evaluation
  • For infants: Most with normal hearing respond to 30 dB nHL tones across frequencies 2

References

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.