Frequency discrimination of short- versus long-duration tones by normal and hearing-impaired listeners.

This investigation explored the effects of stimulus level on the frequency discrimination of long- and short-duration pure tones by 5 subjects with normal hearing and 7 with sensorineural hearing impairment. Frequency difference limens (DLs) were obtained as a function of signal intensity for 5-ms and 300-ms tones at 500, 1000, and 2000 Hz. The performance of most of the hearing-impaired subjects was poorer than normal for 300-ms tones, but not for 5-ms tones. This result was relatively independent of the stimulus sensation levels at which the data were compared. However, the current results also show an unexpected dependence of the frequency DL on the sensation level of short-duration tones. In several normal-hearing subjects, frequency discrimination performance for these short tones is poorer at moderately high levels than at low levels.