Consonant discrimination as a function of presentation level.

This study examined the effect of presentation level (seven levels ranging from 0 to 60 dB re the subject's SRT) on the discrimination of 20 consonants spoken in CV syllables. The subjects were 10 young adults with normal hearing. It was determined that the performance-intensity functions for individual consonants varied widely. Some sounds were not identified correctly 100% of the time even at the highest level tested, whereas other sounds were consistently identified at 10 dB SL. The data were considered with respect to stimulus and response bias and also were subjected to a feature analysis using features of voice, manner and place.

The acoustic reflex and temporary threshold shift: temporal characteristics.

One ear of each of seven normal-hearing subjects was exposed to a continuous 1000-Hz tone at 110 dB SPL for three minutes. During exposure, a broad-band noise at 100 dB SPL was presented to the contralateral ear. The noise was either continuous or pulsed. Four pulsed conditions employed repetition periods of 360, 180, 90, or 9 msec with a 50% duty cycle. A control condition in which no noise was presented was also included. Temporary threshold shift was measured at selected postexposure times at the frequency one-half octave above the exposure frequency. TTS2 was greatest for the control condition and least for the 360- and 180-msec conditions. Results are discussed in relation to the dynamics of the acoustic reflex, particularly reflex relaxation, reflex adaptation, and reflex temporal summation.