Brainstem auditory-evoked responses in horses with temporohyoid osteoarthropathy.
BACKGROUND
Facial and vestibulocochlear nerve dysfunction occurs commonly in horses with temporohyoid osteoarthropathy (THO); however, auditory dysfunction has not been thoroughly assessed.


OBJECTIVE
To determine if auditory abnormalities occur in horses with THO.


METHODS
Eleven diseased and 8 control horses.


METHODS
This is a prospective study in which brainstem auditory-evoked responses (BAER) were recorded in 11 horses diagnosed with THO through neurologic, endoscopic, radiographic, or computed tomographic examinations. BAER findings were compared with those recorded from 8 adult control horses.


RESULTS
All horses with THO were found to have BAER abnormalities that included complete unilateral BAER loss (82%, n=9/11), partial unilateral BAER loss (18%, n=2/11) on the most affected side, and contralateral partial BAER loss (46%, n=5/11). Nine horses had bilateral THO based on diagnostic imaging findings; of these, 5 (56%) horses also had bilateral BAER abnormalities. The complete absence of BAER in affected horses was most consistent with peripheral sensorineural hearing loss. There was a significant association between complete BAER loss and neurologic and diagnostic abnormalities.


CONCLUSIONS
Auditory abnormalities such as complete or partial BAER loss are common in horses with THO. The BAER test is an objective diagnostic tool that can aid along with other diagnostic modalities in the assessment, management, and follow-up of horses with THO. Furthermore, BAER studies may help to elucidate the pathophysiology of THO in horses.
Aleman
M
M
Department of Medicine, School of Veterinary Medicine, University of California, Davis, CA 95616, USA. mraleman@ucdavis.edu
Puchalski
S M
SM
Williams
D C
DC
Kass
P H
PH
Holliday
T A
TA
D000818:Animals; D001847:Bone Diseases / Q000378:metabolism / Q000662:veterinary*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D034381:Hearing Loss / Q000662:veterinary*; D006734:Horse Diseases / Q000378:metabolism*; D006736:Horses; D008297:Male; D011446:Prospective Studies