Peer-reviewed veterinary case report
Brainstem auditory evoked response in the diagnosis of inner ear injury in the horse.
- Journal:
- Journal of the American Veterinary Medical Association
- Year:
- 1981
- Authors:
- Marshall, A E et al.
- Species:
- horse
Plain-English summary
Researchers used a special test called the brainstem auditory evoked response (BAER) to check how well the inner ear and the eighth cranial nerve were working in a horse. This test involves making sounds and measuring the brain's response to those sounds. In a healthy horse, you would see a series of waves shortly after the sound is made, but if there's an injury, those waves might be missing on the affected side. In this case, the BAER test was performed on a horse showing signs of balance problems, and it confirmed there was an injury in one inner ear while ruling out a more serious issue in the brain. The treatment and testing helped pinpoint the problem effectively.
Abstract
Brainstem auditory evoked response (BAER) testing was done to evaluate inner ear/VIIIth cranial nerve (CN8) function in the horse. The BAER test consisted of stimulating the auditory system with clicks and recording far-field responses of the brainstem auditory components via cutaneous electrodes and a signal averaging system. The normal response was shown to be a series of waves occurring within the first 10 msec after the stimulus click. Functional loss of the auditory receptor organ (cochlea) or CN8 results in loss of the entire response on the side of the injury. Because of the anatomic relationships of the peripheral auditory and vestibular systems, trauma to one will injure the other. Therefore, auditory testing (BAER tests) may be used to advantage in the diagnosis of peripheral vestibular disease. The BAER test was used in a horse that had signs suggestive of vestibular dysfunction or a brain lesion. The test helped to demonstrate a unilateral inner ear/CN8 lesion and to discount the probability of a more central lesion.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/6971862/