Click and Low‐, Middle‐, and High‐Frequency Toneburst Stimulation of the Canine Cochlea

Abstract

A method was developed to deliver tonebursts ranging in frequency from 1 to 32 kHz for frequency‐specific assessment of the canine cochlea. Brainstem auditory‐evoked responses (early latency responses, 0–10 ms) to a click (CS) and to 1‐, 2‐, 4‐, 8‐, 12‐, 16‐, 24‐, and 32‐kHz toneburst stimulations (TS) were compared at 80‐dB sound pressure level stimulus (SPL) intensity in 10 adult dogs. All stimulations yielded a 5–7 positive wave pattern, with the exception of the 1‐kHz TS, which evoked a frequency‐following response (FFR). Thresholds were lowest for the CS and the 12‐ and 16‐kHz TS. All individual peak latencies for TS were significantly (P≤ .05) longer than for CS. Peak I latencies were significantly (P≤.05) shorter for the 12‐ and 16‐kHz TS than for the other TS. Interpeak latencies I‐V were significantly (P≤ .05) longer for the 4‐ to 32‐kHz TS than for CS. Differences in interpeak latencies I—III were not significant. Amplitudes of waves I and V were significantly (P≤ .05) lower for TS than for CS, except for higher wave V amplitude (P≤ .05) at 2‐ and 32‐kHz TS. Peak I‐V amplitude ratios were significantly (P≤ .05) higher for the 2‐, 4‐, 16‐, 24‐, and 32‐kHz TS and lower for the 8‐ and 12‐kHz TS, compared to CS. We conclude that reproducible information on frequency specificity of the canine cochlea can be obtained by TS. This report provides a normative database for parameters needed to evaluate frequency‐specific hearing loss in dogs.