title: Loudness Context Effects in Normal-Hearing Listeners and Cochlear-Implant Users.
abstract: Context effects in loudness have been observed in normal auditory perception and may reflect a general gain control of the auditory system. However, little is known about such effects in cochlear-implant (CI) users. Discovering whether and how CI users experience loudness context effects should help us better understand the underlying mechanisms. In the present study, we examined the effects of a long-duration (1-s) intense precursor on the loudness relations between shorter-duration (200-ms) target and comparison stimuli. The precursor and target were separated by a silent gap of 50 ms, and the target and comparison were separated by a silent gap of 2 s. For normal-hearing listeners, the stimuli were narrowband noises; for CI users, all stimuli were delivered as pulse trains directly to the implant. Significant changes in loudness were observed in normal-hearing listeners, in line with earlier studies. The CI users also experienced some loudness changes but, in contrast to the results from normal-hearing listeners, the effect did not increase with increasing level difference between precursor and target. A "dual-process" hypothesis, used to explain earlier data from normal-hearing listeners, may provide an account of the present data by assuming that one of the two mechanisms, involving "induced loudness reduction," was absent or reduced in CI users.
authors.affiliation: Department of Psychology, University of Minnesota, N218 Elliott Hall, 75 East River Rd., Minneapolis, MN, 55455, USA, wang2087@umn.edu.
authors.forename: Ningyuan
authors.initials: N
authors.lastname: Wang
authors.forename: Heather A
authors.initials: HA
authors.lastname: Kreft
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Oxenham
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D003054:Cochlear Implants; D005260:Female; D006801:Humans; D008144:Loudness Perception; D008297:Male; D008875:Middle Aged; D013067:Speech Perception; D055815:Young Adult