Type of Resources
Distortion product otoacoustic emissions (DPOAEs) are part of hearing screening measures and comprehensive audiologic test battery in humans. For canines, the brainstem auditory evoked response (BAER) test is the gold standard for assessing hearing sensitivity. Performing DPOAEs on canines for screening/diagnostic purposes is a relatively new area of research and there is a lack of canine-specific equipment and universally accepted guidelines. The purpose of this research was to determine what stimulus frequency ratios would produce the most robust DPOAEs in canines to support future clinical use and to aid in evaluation of hearing status. Diagnostic DPOAE tests utilizing nine f2/f1 ratios from 1.18-1.28 were completed on the right ear of 10 canines. Results showed consistent DPOAE responses across the f2/f1 ratios tested. The f2/f1 ratios between 1.18 and 1.28 did not produce statistically significantly different DPOAE responses, and the pattern across frequencies did not significantly change when the f2/f1 ratio changed. Lack of DPOAE responses below 2k Hz with low ambient noise and high canine compliance suggests the typical DPOAE response is best at 2k Hz and above. In general, canine DPOAE responses are robust enough that the f2/f1 ratio does not seem to significantly impact overall amplitudes. If DPOAEs are to be utilized as a clinical screening tool at this time, the f2/f1 ratio 1.18-1.22 is recommended because 1.18 and 1.20 had the most robust responses overall. The ratio 1.22, typically used for DPOAEs in humans, would also be acceptable especially if it aided in ease of use.