Gap detection in chinchillas with temporary high-frequency hearing loss.

Estimates of auditory temporal acuity were obtained from normal chinchillas by measuring their gap-detection thresholds using wideband noise over a range of intensities. Afterwards, the animals were exposed to high-intensity noise whose low-frequency cutoff was progressively lowered towards the low frequencies in five 1-oct steps. The five exposures resulted in a temporary high-frequency hearing loss that progressively spread towards the low frequencies. In addition, there was a systematic and orderly increase in the gap-detection thresholds. These results indicate that gap resolution is strongly dependent on the audibility of the high-frequency energy in the test signal.