The long-term objectives of this research are to determine the limitations in auditory analysis associated with sensorineural hearing loss, to discover the mechanisms of peripheral processing that are most affected by cochlear pathology, and to develop ways of assessing the effects of cochlear pathology on auditory analysis. Research into the limitations in auditory temporal analysis focuses on the ability to hear signals during short moments of silence in masking sounds with fluctuating envelopes, much like the fluctuating sounds in our environment that interfere with hearing speech in every day life. Emphasis is placed on a little-studied phenomenon that provides persons with normal hearing with the ability to do better by listening at frequencies far above the frequency of the interfering sound. The lack of that ability in some persons with cochlear hearing loss may account for why they do so poorly in noisy environments. This investigation of that phenomenon promises to provide new information about compressive nonlinearities in the normal ear, and the lack thereof in ears with cochlear hearing loss. In addition, the validity of a new test for assessing these abilities in clinical settings is evaluated. Mechanisms of suppression and excitation are investigated in persons with cochlear hearing loss with the aid of very low-frequency acoustic biasing tones, a procedure that provides a valuable link between human psychophysics and animal physiology. Finally, different techniques for measuring limitations in auditory frequency analysis are compared so that the results of previous research on this grant can be generalized to clinically practicable procedures. Since the measures of auditory analysis proposed here emphasize concepts of interference between one sound and another, the results of this research will have practical implications for preventative, diagnostic, and habilitative aspects of health care for the hearing-impaired patient. In addition, this research will aid our understanding of the mechanisms by which diseases of the ear affect the ability of human listeners to process the sounds around them, particularly speech.
|Wojtczak, M; Schroder, A C; Kong, Y Y et al. (2001) The effect of basilar-membrane nonlinearity on the shapes of masking period patterns in normal and impaired hearing. J Acoust Soc Am 109:1571-86|