The present investigation will focus on subtle temporary changes in human temporal acuity (gap discrimination) brought about by listening to moderatley intense noises for a brief period of time. Test signals will be octave-band noises (center frequencies = 300, 800, and 2000 Ha). Off-frequency spectral cues will be reduced with the application of a simultaneous broad-band notched noise. The study is designed to provide answers to the following research questions: (1) following exposure to noise, is the relationship between the frequency of stimulation and gap discrimination thresholds significantly different from that observed prior to noise exposure; (2) are significant changes in gap discrimination thresholds observable as a function of the amount of time that has elapsed after the termination of the noise and are these changes related to the freequency or intensity of the stimulus; (3) is the relationship between pre- and post-noise gap discrimination thresholds significantly affected by changes in post-noise signal level? The measurement of suprathreshold varibles, rather than absolute sensitivity, may be a more meaningful way of quantifying an individual's susceptibility to noise exposure. Specifically, this investigation of teporal acuity may provide the basis for developing a more sensitive tool for evaluationg the effects of noise on hearing. Information from this study may also help us understand the temporal processing capabilities of some hearing-impaired individuals. Designers of auditory prosthetic devices (e.g., hearing aids and cochlear implants) may be able to develop instruments which allow impaired listeners to make more effective use of their residual temporal resolving capacities, thus enhancing their communicative abilities.
