Brainstem auditory-evoked responses in horses with temporohyoid osteoarthropathy.

The article discusses a study on horses with temporohyoid osteoarthropathy (THO), a disease that commonly causes dysfunction of the facial and vestibulocochlear nervess but has not been thoroughly investigated for auditory impairment. Through the use of brainstem auditory-evoked responses (BAER), the study found auditory abnormalities to be frequent in horses with THO.

Methodology

• The researchers conducted a prospective study in which they used brainstem auditory-evoked responses (BAER), a technique that records the brain’s responses to auditory stimuli, to evaluate hearing function in horses diagnosed with THO.
• The diagnosis of THO was confirmed in these horses through various means including neurologic, endoscopic, radiographic, or computed tomographic examinations.
• The BAER findings from the 11 horses with THO were compared with those recorded from 8 adult horses without the disease, serving as control subjects.

Results

• The results showed that all the horses with THO had some form of BAER abnormalities. This included complete unilateral BAER loss in 82% of horses, partial unilateral BAER loss in 18% of horses, and contralateral partial BAER loss in 46% of the horses.
• It was also found that of the 9 horses diagnosed with bilateral THO through imaging studies, 56% also demonstrated bilateral BAER abnormalities.
• The complete absence of BAER in affected horses was most often indicative of peripheral sensorineural hearing loss, a type of hearing loss that occurs due to damage in the inner ear or the nerve pathways from the inner ear to the brain.
• A significant association was seen between complete BAER loss and neurologic and diagnostic abnormalities in the THO horses.

Conclusions and Implications

• The study concluded that auditory abnormalities such as complete or partial BAER loss are quite common in horses suffering from THO.
• The BAER test was found to be a helpful diagnostic tool that, used in conjunction with other diagnostic methods, can aid in the evaluation, management, and follow-up of horses with THO.
• The findings from BAER tests may also contribute to understanding the pathophysiology, or functional changes that accompany THO in horses, thus potentially guiding future research or treatment approaches.