TY - JOUR
T1 - ECAP spread of excitation with virtual channels and physical electrodes
AU - Hughes, Michelle L.
AU - Stille, Lisa J.
AU - Baudhuin, Jacquelyn L.
AU - Goehring, Jenny L.
N1 - Funding Information:
This research was supported by NIH/NIDCD grants R01 DC009595 and P30 DC04662 . The content of this project is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute on Deafness and Other Communication Disorders or the National Institutes of Health. The authors thank Donna Neff, Adam Goulson, Katelyn Glassman, and Gina Diaz for assistance with data collection; Tom Creutz for data-analysis programs; Kanae Nishi for statistical assistance; Bas Van Dijk (Cochlear Europe) and Peter Busby (Cochlear Australia) for Custom-Sound EP Dual Electrode support; and Leo Litvak and Aniket Saoji (Advanced Bionics) for BEDCS support.
PY - 2013/12
Y1 - 2013/12
N2 - The primary goal of this study was to evaluate physiological spatial excitation patterns for stimulation of adjacent physical electrodes and intermediate virtual channels. Two experiments were conducted that utilized electrically evoked compound action potential (ECAP) spread-of-excitation (SOE) functions obtained with the traditional forward-masking subtraction method. These two experiments examined spatial excitation patterns for virtual-channel maskers and probes, respectively. In Experiment 1, ECAP SOE patterns were obtained for maskers applied to physical electrodes and virtual channels to determine whether virtual-channel maskers yield SOE patterns similar to those predicted from physical electrodes. In Experiment 2, spatial separation of SOE functions was compared for two adjacent physical probe electrodes and the intermediate virtual channel to determine the extent to which ECAP SOE patterns for virtual-channel probes are spatially separate from those obtained with physical electrodes. Data were obtained for three electrode regions (basal, middle, apical) for 35 ears implanted with Cochlear (N=16) or Advanced Bionics (N=19) devices. Results from Experiment 1 showed no significant difference between predicted and measured ECAP amplitudes for Advanced Bionics subjects. Measured ECAP amplitudes for virtual-channel maskers were significantly larger than the predicted amplitudes for Cochlear subjects; however, the difference was <2μV and thus is likely not clinically significant. Results from Experiment 2 showed that the probe set in the apical region demonstrated the least amount of spatial separation amongst SOE functions, which may be attributed to more uniform nerve survival patterns, closer electrode spacing, and/or the tapered geometry of the cochlea. As expected, adjacent physical probes demonstrated greater spatial separation than for comparisons between each physical probe and the intermediate virtual channel. Finally, the virtual-channel SOE functions were generally weighted toward the basal electrode in the pair.
AB - The primary goal of this study was to evaluate physiological spatial excitation patterns for stimulation of adjacent physical electrodes and intermediate virtual channels. Two experiments were conducted that utilized electrically evoked compound action potential (ECAP) spread-of-excitation (SOE) functions obtained with the traditional forward-masking subtraction method. These two experiments examined spatial excitation patterns for virtual-channel maskers and probes, respectively. In Experiment 1, ECAP SOE patterns were obtained for maskers applied to physical electrodes and virtual channels to determine whether virtual-channel maskers yield SOE patterns similar to those predicted from physical electrodes. In Experiment 2, spatial separation of SOE functions was compared for two adjacent physical probe electrodes and the intermediate virtual channel to determine the extent to which ECAP SOE patterns for virtual-channel probes are spatially separate from those obtained with physical electrodes. Data were obtained for three electrode regions (basal, middle, apical) for 35 ears implanted with Cochlear (N=16) or Advanced Bionics (N=19) devices. Results from Experiment 1 showed no significant difference between predicted and measured ECAP amplitudes for Advanced Bionics subjects. Measured ECAP amplitudes for virtual-channel maskers were significantly larger than the predicted amplitudes for Cochlear subjects; however, the difference was <2μV and thus is likely not clinically significant. Results from Experiment 2 showed that the probe set in the apical region demonstrated the least amount of spatial separation amongst SOE functions, which may be attributed to more uniform nerve survival patterns, closer electrode spacing, and/or the tapered geometry of the cochlea. As expected, adjacent physical probes demonstrated greater spatial separation than for comparisons between each physical probe and the intermediate virtual channel. Finally, the virtual-channel SOE functions were generally weighted toward the basal electrode in the pair.
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U2 - 10.1016/j.heares.2013.09.014
DO - 10.1016/j.heares.2013.09.014
M3 - Article
C2 - 24095669
AN - SCOPUS:84885900815
SN - 0378-5955
VL - 306
SP - 93
EP - 103
JO - Hearing Research
JF - Hearing Research
ER -