Document Detail

Forward masking in different cochlear implant systems.
MedLine Citation:
PMID:  14587605     Owner:  NLM     Status:  MEDLINE    
The goal of this study was to evaluate, from a psychophysical standpoint, the neural spread of excitation produced by the stimulation of different types of intracochlear electrode arrays: the Ineraid, the Clarion S-Series on its own or with the Electrode Positioning System (EPS), and the Clarion HiFocus-I with the EPS. The EPS is an independent silicone part designed to bring the electrode array close to the modiolus. Forward masking was evaluated in 12 adult subjects (3 Ineraid, 4 Clarion S-Series, 3 Clarion S-Series+EPS, 3 HiFocus-I+EPS) by psychophysical experiments conducted using trains of biphasic stimuli (813 pulses per second, 307.6 micros/phase). Masker signals (+8 dB re: threshold, 300 ms) were applied to the most apical electrode. Probe signals (30 ms, 10-ms postmasker) were delivered to more basal electrodes. Masked and unmasked detection thresholds of probe signals were measured. For both Clarion HiFocus-I subjects, measurements were conducted in both monopolar and bipolar stimulus configurations. No major differences were found in forward masking between the different intracochlear electrode arrays tested in the monopolar configuration at suprathreshold levels equivalent to those used in speech-coding strategies, but significant differences were found between subjects. A significant negative correlation also was found between the level of forward masking and the consonant identification performance. These measurements showed that the neural spread of excitation was more restricted in the bipolar configuration than in the monopolar configuration for HiFocus-I subjects. It was found that CIS strategies implemented without using apical electrodes, which showed high levels of masking, could improve consonant identification.
Colette Boëx; Maria-Izabel Kós; Marco Pelizzone
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of the Acoustical Society of America     Volume:  114     ISSN:  0001-4966     ISO Abbreviation:  J. Acoust. Soc. Am.     Publication Date:  2003 Oct 
Date Detail:
Created Date:  2003-10-31     Completed Date:  2004-01-14     Revised Date:  2006-12-27    
Medline Journal Info:
Nlm Unique ID:  7503051     Medline TA:  J Acoust Soc Am     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2058-65     Citation Subset:  IM    
Centre Romand d'Implants Cochléaires, University Hospital, Geneva, Switzerland.
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MeSH Terms
Auditory Threshold / physiology*
Cochlear Implants*
Cochlear Nerve / physiopathology
Deafness / etiology,  physiopathology,  rehabilitation*
Electric Conductivity
Electrodes, Implanted*
Middle Aged
Perceptual Masking / physiology*
Prosthesis Design
Speech Perception / physiology*
Speech Reception Threshold Test

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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