Endoscopic findings of the external ear canal in a group of clinically normal horses and horses with head shaking or vestibular disease.

The research article presents a study aimed at standardizing the otoscopic examination of horses in order to identify ear-related diseases and understand the normal appearance of equine ear canals and tympanic membrane. The study utilized video endoscopes in standing, sedated horses and found evidence of several ear diseases while creating a reference for normal ear appearance.

Study Design & Participants

• The research study involved 38 randomly selected horses that were chemically restrained.
• Two of these horses had vestibular disease and three exhibited head shaking. The rest had no signs or history of ear-associated diseases.
• The researchers performed otoscopic examinations on both ears of each horse.

Methodology

• The researchers used common veterinary video endoscopes, typically used for gastroscopy or bronchoscopy, to perform the otoscopic examinations.
• They created references for the normal appearance of the equine external ear canal (EEEC) and tympanic membrane (TM) based on several parameters like anatomical landmarks, degree of debris, and keratin layer formation among others.

Findings

• The study identified cases of tympanosclerosis in two horses and varying degrees of external otitis in three others.
• One horse with severe bilateral external otitis was also found to have temporohyoid osteoarthropathy (THO), a disease of the bone and joint in the hyoid apparatus and temporal bone that can affect balance and hearing in horses.
• A foreign body was found in one horse’s external ear canal.

Conclusions

• The research concludes that otoscopic examination is a simple and effective diagnostic procedure that should form part of the comprehensive assessment of ear-related diseases in horses.
• It also emphasizes the role of noise exposure in affecting the well-being of horses, suggesting a need for more research on equine audiological aspects.

Impact and Future Directions

• The standardized otoscopic examination, as suggested by the study, provides a valuable foundation for further research on aural diseases in horses.
• This study can also help veterinarians in quickly diagnosing and accurately treating ear-related diseases in horses, thereby improving their well-being and health outcomes.