Impedance audiometric measurements in clinically normal dogs

Area of Science:

• Veterinary Medicine
• Audiology
• Animal Physiology

Background:

• Impedance audiometry is a valuable diagnostic tool in veterinary medicine.
• Establishing reference ranges for impedance audiometric values in dogs is crucial for accurate diagnosis.
• Previous studies have not fully evaluated the impact of sedation, anesthesia, and ear flushing on these measurements.

Purpose of the Study:

• To establish reference impedance audiometric values in clinically normal dogs under sedation or anesthesia.
• To assess the influence of ear flushing on tympanometric measurements.
• To determine the necessity of a sound-attenuated room for acoustic reflex testing in dogs.

Main Methods:

• Impedance audiometry, including tympanometry and acoustic reflex testing, was performed on mixed-breed dogs and Beagles under isoflurane or halothane anesthesia, or sedation.
• Tympanometry was conducted before and after ear canal flushing in a subset of dogs.
• Procedures were carried out in both sound-attenuated and non-sound-attenuated environments.

Main Results:

• Ear canal volume and compliance peak were smaller in Beagles compared to mixed-breed dogs, with ear canal volume correlating with body weight.
• No significant differences were observed in tympanometric values before and after ear canal flushing.
• Acoustic reflex testing yielded comparable results regardless of whether it was performed in a sound-attenuated room.

Conclusions:

• Reference ranges for impedance audiometry in sedated or anesthetized dogs were successfully established.
• Acoustic reflex testing in dogs does not require a sound-attenuated environment.
• Ear flushing prior to tympanometry does not alter impedance audiometric results in clinically normal dogs.
• Impedance audiometry is a potentially useful noninvasive method for diagnosing otitis media in dogs.