Multimodal Approaches to Hearing Testing in Veterinary Medicine

Presentation Description / Summary: Hearing screening is well established in veterinary practice for the routine diagnosis of congenital unilateral and bilateral deafness. The gold standard for hearing screening is the recording of brainstem auditory evoked responses (BAER) with click stimuli. This method offers also options for a more detailed audiometric assessment, i. e. measurements of hearing thresholds, comparing hearing thresholds between air- and bone-conducted stimuli, or to record an audiogram with narrow-band tone or pip stimuli. However, long examination times together with the need for deep sedation or anesthesia are considerable limitations for an expanded hearing test in geriatric and diseased cases. Next generation hearing screening methods from newborn hearing screening offer solutions to overcome this gap. This talk provides in its first part an introduction into the physiology and pathophysiology of hearing and the current literature on audiometric evaluation in veterinary patients. The second part introduces objective test methods derived from newborn hearing screening i. e. 2 minute rapid click hearing threshold assessment, otoacoustic emissions (OAE) and auditory steady-state responses (ASSR). ASSR and OAE (DPOAE) can assess responses of the brain or the hair cells over a range of frequencies. The resulting audiogram routinely covers frequencies from1 to 8 kHz. The third part gives insights into the clinical use in dogs presenting for hearing testing or vestibular disease, and expands also on research applications in a transgenic model of Usher disease in pigs. Next-generation hearing testing could be a robust supplement of the neurologic diagnostic work-up in veterinary practice.

Learner Outcomes: 1. The learner will recognize the different modes of hearing testing 2. The learner will recall and understand common failures in hearing testing