Electrically evoked compound action potential(e CAP) amplitudes elicited at suprathreshold levels were assessed as a measure of the effectiveness of cochlear implant(CI) stimulation. Twenty-one individuals participate...Electrically evoked compound action potential(e CAP) amplitudes elicited at suprathreshold levels were assessed as a measure of the effectiveness of cochlear implant(CI) stimulation. Twenty-one individuals participated; one was excluded due to facial stimulation during e CAP testing. For each participant, e CAPs were elicited with stimulation from seven electrodes near the upper limit of the individual's electrical dynamic range. A reduced-channel CI program was created using those same seven electrodes, and participants performed a vowel discrimination task. Consistent with previous reports, e CAP amplitudes varied across tested electrodes; the profiles were unique to each individual. In 6subjects(30%), e CAP amplitude variability was partially explained by the impedance of the recording electrode. The remaining amplitude variability within subjects, and the variability observed across subjects could not be explained by recording electrode impedance. This implies that other underlying factors, such as variations in neural status across the array, are responsible. Across-site mean e CAP amplitude was significantly correlated with vowel discrimination scores(r^2= 0.56). A single e CAP amplitude measured from the middle of the array was also significantly correlated with vowel discrimination, but the correlation was weaker(r^2= 0.37), though not statistically different from the acrosssite mean. Normalizing each e CAP amplitude by its associated recording electrode impedance did not improve the correlation with vowel discrimination(r^2= 0.52). Further work is needed to assess whether combining e CAP amplitude with other measures of the electrode-neural interface and/or with more central measures of auditory function provides a more complete picture of auditory function in CI recipients.展开更多
ECAPs are the summary of multiple neurons’ spikes which could be recorded by a bidirectional stimulation-recording system via the cochlear implant,with the artifact elimination paradigms of forward-masking subtractio...ECAPs are the summary of multiple neurons’ spikes which could be recorded by a bidirectional stimulation-recording system via the cochlear implant,with the artifact elimination paradigms of forward-masking subtraction paradigm or alternating polarity paradigm.Three kinds of FDA approved cochlear implants support ECAP testing.This article is to summarize the clinical application of ECAP lest.ECAP test after insertion of electrode during implant operation has been widely used during cochlear implant surgery.In recent years.ECAP thresholds are also used to estimate the T levels and C levels helping programming.However,correlation between ECAP thresholds and psychophysical thresholds is affected by many factors.So far,ECAPs cannot yet be a good indicator of post-operative hearing and speech performance.展开更多
基金supported by the National Institutes of Health, National Institute on Deafness and Other Communication Disorders under the following grants awarded to the University of Iowa: F31DC013202, P50DC000242, and R01DC012082funded in part by the University of Iowa Department of Communication Sciences and Disorders
文摘Electrically evoked compound action potential(e CAP) amplitudes elicited at suprathreshold levels were assessed as a measure of the effectiveness of cochlear implant(CI) stimulation. Twenty-one individuals participated; one was excluded due to facial stimulation during e CAP testing. For each participant, e CAPs were elicited with stimulation from seven electrodes near the upper limit of the individual's electrical dynamic range. A reduced-channel CI program was created using those same seven electrodes, and participants performed a vowel discrimination task. Consistent with previous reports, e CAP amplitudes varied across tested electrodes; the profiles were unique to each individual. In 6subjects(30%), e CAP amplitude variability was partially explained by the impedance of the recording electrode. The remaining amplitude variability within subjects, and the variability observed across subjects could not be explained by recording electrode impedance. This implies that other underlying factors, such as variations in neural status across the array, are responsible. Across-site mean e CAP amplitude was significantly correlated with vowel discrimination scores(r^2= 0.56). A single e CAP amplitude measured from the middle of the array was also significantly correlated with vowel discrimination, but the correlation was weaker(r^2= 0.37), though not statistically different from the acrosssite mean. Normalizing each e CAP amplitude by its associated recording electrode impedance did not improve the correlation with vowel discrimination(r^2= 0.52). Further work is needed to assess whether combining e CAP amplitude with other measures of the electrode-neural interface and/or with more central measures of auditory function provides a more complete picture of auditory function in CI recipients.
基金supported by grants from the National Basic Research Program of China(973 Program)(#2012CB967900)Science and Technology Innovation Nursery Foundation of PLA General Hospital(13KMM14)Clinical Research Supporting Foundation of PLA General Hospital(2012FC-TSYS-3056)
文摘ECAPs are the summary of multiple neurons’ spikes which could be recorded by a bidirectional stimulation-recording system via the cochlear implant,with the artifact elimination paradigms of forward-masking subtraction paradigm or alternating polarity paradigm.Three kinds of FDA approved cochlear implants support ECAP testing.This article is to summarize the clinical application of ECAP lest.ECAP test after insertion of electrode during implant operation has been widely used during cochlear implant surgery.In recent years.ECAP thresholds are also used to estimate the T levels and C levels helping programming.However,correlation between ECAP thresholds and psychophysical thresholds is affected by many factors.So far,ECAPs cannot yet be a good indicator of post-operative hearing and speech performance.
