Ascending and descending thresholds of pure tones

Fixed frequency Bekesy threshold measurements were made for subjects with normal hearing and hearing impairment. Ascending (no sound to sound) and descending (sound to no sound) methods were used for both continuous tones and tones interrupted 212 times per second with attenuation rates of 2.5 and 5.0 dB/s. For ascending method, the ratio of time to reach the first appearance of tone by slow and fast attenuation rates was 2:1. For descending method, the ratio of time to reach the first disappearance of tone was 1.6‐1.7:1. There were no observable differences in these ratios for various frequencies, starting intensities, interrupted and continuous tones, and for subjects with normal hearing and hearing impairment. The ratio of 2:1 was the same as the speed of mechanical attenuation rates. The ratio of 1.6‐1.7:1 may suggest that the slower attenuation rate decreased speed of machine relatively slower than mechanism of adaptation. In conventional automatic audiometry, pulsed tones are interrupted 212 times p...