title: Cortical auditory evoked potentials as an objective measure of behavioral thresholds in cochlear implant users.
abstract: The aim of this study was to assess the suitability of using cortical auditory evoked potentials (CAEPs) as an objective tool for predicting behavioral hearing thresholds in cochlear implant (CI) users. Nine experienced adult CI users of Cochlear(™) devices participated. Behavioral thresholds were measured in CI users across apical, mid and basal electrodes. CAEPs were measured for the same stimuli (50 ms pulse trains of 900-pps rate) at a range of input levels across the individual's psychophysical dynamic range (DR). Amplitude growth functions using global field power (GFP) were plotted, and from this the CAEP thresholds were extrapolated and compared to the behavioral thresholds. Increased amplitude and decreased latency of the N1-P2 response was seen with increasing input level. A strong correlation was found between CAEP and behavioral thresholds (r = 0.93), implying that the cortical response may be more useful as an objective programming tool for cochlear implants than the auditory nerve response.
authors.affiliation: School of Psychological Sciences, University of Manchester, UK; Audiology Department, Betsi Cadwaladr University Health Board, UK. Electronic address: anisavisram@hotmail.com.
authors.forename: Anisa S
authors.initials: AS
authors.lastname: Visram
authors.affiliation: The Bionics Institute of Australia, Australia; Department of Medical Bionics, University of Melbourne, Australia. Electronic address: hinnes-brown@bionicsinstitute.org.
authors.forename: Hamish
authors.initials: H
authors.lastname: Innes-Brown
authors.affiliation: School of Psychological Sciences, University of Manchester, UK. Electronic address: wael.el-deredy@manchester.ac.uk.
authors.forename: Wael
authors.initials: W
authors.lastname: El-Deredy
authors.affiliation: School of Psychological Sciences, University of Manchester, UK; The Bionics Institute of Australia, Australia; Department of Medical Bionics, University of Melbourne, Australia. Electronic address: cmckay@bionicsinstitute.org.
authors.forename: Colette M
authors.initials: CM
authors.lastname: McKay
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001303:Auditory Cortex / Q000503:physiopathology*; D001309:Auditory Threshold; D019929:Cochlear Implantation / Q000295:instrumentation*; D003054:Cochlear Implants; D003056:Cochlear Nerve / Q000503:physiopathology; D004558:Electric Stimulation; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019986:Persons with Hearing Disabilities / Q000523:psychology / Q000534:rehabilitation*; D011571:Psychoacoustics; D011930:Reaction Time; D013997:Time Factors