A reliable and holistic approach to evaluating hearing and cognitive auditory processing in adult and aged companion dogs

Presbycusis affects both peripheral and central auditory systems in people and dogs. While comprehensive behavioral hearing tests exist for people, veterinary audiology lacks methods to assess central auditory function in dogs. This study aimed to develop behavioral hearing tests for dogs. We introduced two novel assessments: the Enclosed Canine Hearing Observation (ECHO) test and the Evaluation of Auditory Reward Response (EARR) test. Fourteen adult dogs with normal hearing, five deaf and five senior dogs were included. The ECHO test evaluates a dog's ability to detect sounds; only hearing dogs responded to sounds with behaviors such as orienting the head or body towards the sound source. The EARR test assesses integration of auditory perception with learning and memory by associating sound cues with rewards; hearing dogs successfully learned and completed the sound-reward task while deaf dogs did not. Senior dogs were able to perform both tasks. Our findings confirmed that these tests are feasible in companion dogs and can differentiate between those with normal hearing and those with hearing impairment. Furthermore, both tests showed high test-retest, intra- and inter-observer reliability. These tests can be paired with electrophysiological tests and MRI evaluations, advancing our ability to detect and characterize presbycusis in dogs.