Brainstem auditory evoked responses and bone conduction assessment in alpacas.

Area of Science:

• Veterinary Medicine
• Neuroscience
• Audiology

Background:

• Auditory loss has been documented in camelids, primarily using brainstem auditory evoked responses (BAER).
• The distinction between conductive and sensorineural auditory dysfunction in alpacas has not been previously investigated.

Purpose of the Study:

• To investigate auditory function in alpacas using both BAER and bone conduction (BC) testing.
• To differentiate between conductive and sensorineural auditory loss in this species.

Main Methods:

• A randomized clinical trial involving 24 alpacas (15 female, 9 male, aged 2-16 years).
• BAER and BC were recorded using two derivations.
• Alpacas underwent physical examinations and sedation with xylazine hydrochloride.

Main Results:

• Thirteen out of 24 alpacas exhibited auditory loss based on BAER results.
• Bone conduction testing supported conductive auditory loss in 6 alpacas, with other cases being difficult to interpret or showing absent peaks.
• Presumed causes included otitis (6 alpacas), aging (4 alpacas), and congenital sensorineural loss (3 alpacas).

Conclusions:

• Brainstem auditory evoked responses and bone conduction are effective, non-invasive techniques for assessing auditory loss in alpacas.
• These methods facilitate the characterization of auditory dysfunction as either conductive or sensorineural.