Use of the acoustic reflex threshold at 3 kc/s for setting optimal click-presentation level in ABR testing

Area of Science:

• Audiology
• Neuroscience
• Hearing Science

Background:

• Noise-exposed hearing loss affects young individuals.
• Acoustic reflex (AR) and auditory brainstem response (ABR) are key audiological assessments.
• Optimizing ABR parameters is crucial for accurate hearing loss diagnosis.

Purpose of the Study:

• To determine the optimal click level for ABR testing in individuals with noise-induced hearing loss.
• To evaluate the relationship between acoustic reflex thresholds and ABR Wave V latency.

Main Methods:

• Ten young men with normal otoscopic and tympanometric findings but noise-exposed hearing loss were recruited.
• Acoustic reflex (AR) thresholds at 3 kHz were measured.
• Auditory brainstem response (ABR) Wave V latency was assessed at click levels equivalent to the AR threshold and at +5 dB and +10 dB above it.

Main Results:

• At the equivalent AR threshold, 6 out of 10 participants showed normal Wave V latency.
• At +5 dB and +10 dB above the AR threshold, all 10 participants exhibited normal Wave V latency.
• This suggests a specific click level adjustment for ABR in this population.

Conclusions:

• An optimal click level setting for ABR diagnostics in noise-exposed hearing loss is approximately +5 dB re AR threshold at 3 kHz.
• This finding is specific to the tested shielded circumaural earphone/cushion unit.
• Further research may validate this optimal setting across different equipment and populations.