Relationship among the physiologic channel interactions, spectral-ripple discrimination, and vowel identification in cochlear implant users.
The hypothesis of this study was that broader patterns of physiological channel interactions in the local region of the cochlea are associated with poorer spectral resolution in the same region. Electrically evoked compound action potentials (ECAPs) were measured for three to six probe electrodes per subject to examine the channel interactions in different regions across the electrode array. To evaluate spectral resolution at a confined location within the cochlea, spectral-ripple discrimination (SRD) was measured using narrowband ripple stimuli with the bandwidth spanning five electrodes: Two electrodes apical and basal to the ECAP probe electrode. The relationship between the physiological channel interactions, spectral resolution in the local cochlear region, and vowel identification was evaluated. Results showed that (1) there was within- and across-subject variability in the widths of ECAP channel interaction functions and in narrowband SRD performance, (2) significant correlations were found between the widths of the ECAP functions and narrowband SRD thresholds, and between mean bandwidths of ECAP functions averaged across multiple probe electrodes and broadband SRD performance across subjects, and (3) the global spectral resolution reflecting the entire electrode array, not the local region, predicts vowel identification.
University of Tennessee Health Science Center, Knoxville, Tennessee 37996.
Jong Ho
JH
Won
University of Tennessee Health Science Center, Knoxville, Tennessee 37996.
Elizabeth L
EL
Humphrey
University of Tennessee Health Science Center, Knoxville, Tennessee 37996.
Kelly R
KR
Yeager
University of Tennessee Health Science Center, Knoxville, Tennessee 37996.
Alexis A
AA
Martinez
University of Tennessee Health Science Center, Knoxville, Tennessee 37996.
Camryn H
CH
Robinson
University of Tennessee Health Science Center, Knoxville, Tennessee 37996.
Kristen E
KE
Mills
University of Tennessee Health Science Center, Knoxville, Tennessee 37996.
Patti M
PM
Johnstone
Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, School of Medicine, Sungkyunkwan University, Seoul, 135-710, South Korea.
Il Joon
IJ
Moon
Department of Biomedical Engineering, University of Ulsan, Ulsan, 680-749, South Korea.
Jihwan
J
Woo
D000200:Action Potentials; D000368:Aged; D000369:Aged, 80 and over; D003051:Cochlea / Q000503:physiopathology*; D003054:Cochlear Implants; D004192:Discrimination, Psychological; D004567:Electrodes, Implanted; D004867:Equipment Design; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D034381:Hearing Loss / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D008875:Middle Aged; D046709:Pattern Recognition, Physiological; D010700:Phonetics; D011571:Psychoacoustics; D013016:Sound; D013067:Speech Perception / Q000502:physiology*