Document Detail


Forward-masking patterns produced by symmetric and asymmetric pulse shapes in electric hearing.
MedLine Citation:
PMID:  20058980     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Two forward-masking experiments were conducted with six cochlear implant listeners to test whether asymmetric pulse shapes would improve the place-specificity of stimulation compared to symmetric ones. The maskers were either cathodic-first symmetric biphasic, pseudomonophasic (i.e., with a second anodic phase longer and lower in amplitude than the first phase), or "delayed pseudomonophasic" (identical to pseudomonophasic but with an inter-phase gap) stimuli. In experiment 1, forward-masking patterns for monopolar maskers were obtained by keeping each masker fixed on a middle electrode of the array and measuring the masked thresholds of a monopolar signal presented on several other electrodes. The results were very variable, and no difference between pulse shapes was found. In experiment 2, six maskers were used in a wide bipolar (bipolar+9) configuration: the same three pulse shapes as in experiment 1, either cathodic-first relative to the most apical or relative to the most basal electrode of the bipolar channel. The pseudomonophasic masker showed a stronger excitation proximal to the electrode of the bipolar pair for which the short, high-amplitude phase was anodic. However, no difference was obtained with the symmetric and, more surprisingly, with the delayed pseudomonophasic maskers. Implications for cochlear implant design are discussed.
Authors:
Olivier Macherey; Astrid van Wieringen; Robert P Carlyon; Ingeborg Dhooge; Jan Wouters
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of the Acoustical Society of America     Volume:  127     ISSN:  1520-8524     ISO Abbreviation:  J. Acoust. Soc. Am.     Publication Date:  2010 Jan 
Date Detail:
Created Date:  2010-01-11     Completed Date:  2010-03-01     Revised Date:  2010-12-17    
Medline Journal Info:
Nlm Unique ID:  7503051     Medline TA:  J Acoust Soc Am     Country:  United States    
Other Details:
Languages:  eng     Pagination:  326-38     Citation Subset:  IM    
Affiliation:
ExpORL, Department of Neurosciences, KU Leuven, Herestraat 49, Bus 721, 3000 Leuven, Belgium. olivier.macherey@mrc-cbu.cam.ac.uk
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MeSH Terms
Descriptor/Qualifier:
Acoustic Stimulation
Acoustics*
Adult
Aged
Analysis of Variance
Auditory Perception*
Auditory Threshold
Cochlear Implants*
Deafness / physiopathology,  therapy
Humans
Middle Aged
Neurons / physiology
Perceptual Masking*
Psychoacoustics
Signal Processing, Computer-Assisted
Time Factors
Grant Support
ID/Acronym/Agency:
080216//Wellcome Trust

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


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