Evaluation of Auditory Brainstem Response in Chicken Hatchlings

Area of Science:

• Auditory Neuroscience
• Animal Models in Hearing Research
• Clinical Audiology

Background:

• Auditory brainstem response (ABR) is crucial for assessing auditory function in various models.
• Chicken hatchlings offer a valuable model due to near-mature auditory systems.
• Updated ABR recording methods for chickens have been lacking for decades.

Purpose of the Study:

• To establish and validate reliable methods for in-vivo ABR recordings in chicken hatchlings.
• To characterize ABR waveform parameters and their relationship to stimulus intensity and physiological factors.
• To provide a foundation for comparative studies of auditory function across species.

Main Methods:

• Utilized subdermal needle electrode arrays for one or two-channel ABR recordings in chicken hatchlings.
• Employed suprathreshold click stimuli and analyzed waveform peaks within the first 6 ms.
• Standardized earphone placement and monitored animal body temperature during recordings.

Main Results:

• Consistently recorded 3-4 positive-going peak waveforms with amplitudes of 2-11 µV at high intensities.
• Observed expected latency-intensity functions, with peak latencies increasing as intensity decreased.
• Identified effects of body temperature and age (young vs. older hatchlings) on ABR parameters, suggesting potential conductive issues in very young birds.

Conclusions:

• The described ABR methods allow for accurate and reproducible in-vivo auditory function assessment in chicken hatchlings.
• These methods can be applied across different developmental stages in chickens.
• Findings facilitate comparisons with human and mammalian hearing loss, aging, and auditory manipulation studies.