title: Temporal suppression of the click-evoked otoacoustic emission level-curve.
abstract: The click-evoked otoacoustic emission (CEOAE) level-curve grows linearly for clicks below 40-60 dB and saturates for higher inputs. This study investigates dynamic (i.e., time-dependent) features of the CEOAE level-curve by presenting a suppressor-click less than 8 ms before the test-click. An alteration of the CEOAE level-curve, designated here as temporal suppression, was observed within this time period, and was shown to depend on the levels and the temporal separation of the two clicks. Temporal suppression occurred for all four subjects tested, and resulted in a vertical offset from the unsuppressed level-curve for test-click levels greater than 50 dB peak-equivalent level (peSPL). Temporal suppression was greatest for suppressors presented 1-4 ms before the test click, and the magnitude and time scale of the effect were subject dependent. Temporal suppression was furthermore observed for the short- (i.e., 6-18 ms) and long-latency (i.e., 24-36 ms) regions of the CEOAE, indicating that temporal suppression similarly affects synchronized spontaneous otoacoustic emissions (SSOAEs) and purely evoked CEOAE components. Overall, this study demonstrates that temporal suppression of the CEOAE level-curve reflects a dynamic process in human cochlear processing that works on a time scale of 0-10 ms.
authors.affiliation: Department of Electrical Engineering, Centre for Applied Hearing Research, Technical University of Denmark, Ørsteds plads Building 352, 2800 Kongens Lyngby, Denmark. sv@elektro.dtu.dk
authors.forename: Sarah
authors.initials: S
authors.lastname: Verhulst
authors.forename: James M
authors.initials: JM
authors.lastname: Harte
authors.forename: Torsten
authors.initials: T
authors.lastname: Dau
mesh_terms: D000161:Acoustic Stimulation; D001309:Auditory Threshold; D003051:Cochlea / Q000502:physiology*; D005072:Evoked Potentials, Auditory; D006801:Humans; D017084:Otoacoustic Emissions, Spontaneous; D011930:Reaction Time; D017603:Signal Detection, Psychological; D013997:Time Factors