Across-Site Threshold Variation in Cochlear Implants: Relation to Speech Recognition

Pfingst, Bryan E.; Xu, Li; Thompson, Catherine S.

doi:10.1159/000081283

Cited by 58 publications

(46 citation statements)

References 15 publications

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“…Clinical research has shown a correlation between the DR and speech perception that endorses the need for setting the proper fitting levels for cochlear implants [Blamey et al, 1992;Pfingst and Xu, 2005;Pfingst et al, 2004;van der Beek et al, 2015]. The aim of the present study was to determine whether radiological data provided additional information for setting the speech processor map levels.…”

Section: Discussionmentioning

confidence: 91%

Intracochlear Position of Cochlear Implants Determined Using CT Scanning versus Fitting Levels: Higher Threshold Levels at Basal Turn

Beek

Briaire²,

Marel³

et al. 2016

Audiol Neurotol

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Objectives: In this study, the effects of the intracochlear position of cochlear implants on the clinical fitting levels were analyzed. Design: A total of 130 adult subjects who used a CII/HiRes 90K cochlear implant with a HiFocus 1/1J electrode were included in the study. The insertion angle and the distance to the modiolus of each electrode contact were determined using high-resolution CT scanning. The threshold levels (T-levels) and maximum comfort levels (M-levels) at 1 year of follow-up were determined. The degree of speech perception of the subjects was evaluated during routine clinical follow-up. Results: The depths of insertion of all the electrode contacts were determined. The distance to the modiolus was significantly smaller at the basal and apical cochlear parts compared with that at the middle of the cochlea (p < 0.05). The T-levels increased toward the basal end of the cochlea (3.4 dB). Additionally, the M-levels, which were fitted in our clinic using a standard profile, also increased toward the basal end, although with a lower amplitude (1.3 dB). Accordingly, the dynamic range decreased toward the basal end (2.1 dB). No correlation was found between the distance to the modiolus and the T-level or the M-level. Furthermore, the correlation between the insertion depth and stimulation levels was not affected by the duration of deafness, age at implantation or the time since implantation. Additionally, the T-levels showed a significant correlation with the speech perception scores (p < 0.05). Conclusions: The stimulation levels of the cochlear implants were affected by the intracochlear position of the electrode contacts, which were determined using postoperative CT scanning. Interestingly, these levels depended on the insertion depth, whereas the distance to the modiolus did not affect the stimulation levels. The T-levels increased toward the basal end of the cochlea. The level profiles were independent of the overall stimulation levels and were not affected by the biographical data of the patients, such as the duration of deafness, age at implantation or time since implantation. Further research is required to elucidate how fitting using level profiles with an increase toward the basal end of the cochlea benefits speech perception. Future investigations may elucidate an explanation for the effects of the intracochlear electrode position on the stimulation levels and might facilitate future improvements in electrode design.

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Section: Discussionmentioning

confidence: 91%

Intracochlear Position of Cochlear Implants Determined Using CT Scanning versus Fitting Levels: Higher Threshold Levels at Basal Turn

Beek

Briaire²,

Marel³

et al. 2016

Audiol Neurotol

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“…The ECAP recording could be used to determine the level of stimulation along the cochlea (Brill et al, 2009), although significant variation amongst patients exist; particularly between adults and children (Dorman et al, 2007;McKay et al, 2013;Pfingst and Xu, 2005;Pfingst et al, 2004); there is evidence that indicates that ECAP measurements can be used to estimate the required stimulation and are a good indicator of post-operative performance (Cafarelli Dees et al, 2005;Eisen and Franck, 2004;Kim et al, 2011;Van Den Abbeele et al, 2012). The presence of an increased ECAP amplitude and steeper slope in the apical region of the cochlea, in the present study, supports the usefulness of ECAP recordings in the apical region of the cochlea.…”

Section: Discussionmentioning

confidence: 99%

Electrically evoked compound action potentials are different depending on the site of cochlear stimulation

Heyning

Arauz²,

Atlas

et al. 2016

Cochlear Implants International

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One of the many parameters that can affect cochlear implant (CI) users' performance is the site of presentation of electrical stimulation, from the CI, to the auditory nerve. Evoked compound action potential (ECAP) measurements are commonly used to verify nerve function by stimulating one electrode contact in the cochlea and recording the resulting action potentials on the other contacts of the electrode array.The present study aimed to determine if the ECAP amplitude differs between the apical, middle, and basal region of the cochlea, if double peak potentials were more likely in the apex than the basal region of the cochlea, and if there were differences in the ECAP threshold and recovery function across the cochlea.ECAP measurements were performed in the apical, middle, and basal region of the cochlea at fixed sites of stimulation with varying recording electrodes. One hundred and forty one adult subjects with severe to profound sensorineural hearing loss fitted with a Standard or FLEX SOFT electrode were included in this study. ECAP responses were captured using MAESTRO System Software (MED-EL). The ECAP amplitude, threshold, and slope were determined using amplitude growth sequences. The 50% recovery rate was assessed using independent single sequences that have two stimulation pulses (a masker and a probe pulse) separated by a variable inter-pulse interval. For all recordings, ECAP peaks were annotated semi-automatically.ECAP amplitudes were greater upon stimulation of the apical region compared to the basal region of the cochlea. ECAP slopes were steeper in the apical region compared to the basal region of the cochlea and 251 ECAP thresholds were lower in the middle region compared to the basal region of the cochlea. The incidence of double peaks was greater upon stimulation of the apical region compared to the basal region of the cochlea. This data indicates that the site and intensity of cochlear stimulation affect ECAP properties.

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“…This suggests an uneven distribution of pathology along the tonotopic axis. Across-site variation has been found for various psychophysical measures (Zwolan et al, 1997;Pfingst et al, 2004;Pfingst and Xu, 2005;Bierer, 2007;Bierer and Faulkner, 2010;Pfingst et al, 2008;Garadat et al, 2012), and the patterns in which these psychophysical measures vary across the stimulation sites are also unique to each measure (Pfingst et al, 2011a). The unique patterns suggest that the various psychophysical measures are not mediated by a single mechanism.…”

Section: A Across-site Variationmentioning

confidence: 98%

Relationship between multipulse integration and speech recognition with cochlear implants

Zhou

Pfingst

2014

The Journal of the Acoustical Society of America

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Comparisons of performance with cochlear implants and postmortem conditions in the cochlea in humans have shown mixed results. The limitations in those studies favor the use of within-subject designs and non-invasive measures to estimate cochlear conditions. One non-invasive correlate of cochlear health is multipulse integration, established in an animal model. The present study used this measure to relate neural health in human cochlear implant users to their speech recognition performance. The multipulse-integration slopes were derived based on psychophysical detection thresholds measured for two pulse rates (80 and 640 pulses per second). A within-subject design was used in eight subjects with bilateral implants where the direction and magnitude of ear differences in the multipulse-integration slopes were compared with those of the speech-recognition results. The speech measures included speech reception threshold for sentences and phoneme recognition in noise. The magnitude of ear difference in the integration slopes was significantly correlated with the magnitude of ear difference in speech reception thresholds, consonant recognition in noise, and transmission of place of articulation of consonants. These results suggest that multipulse integration predicts speech recognition in noise and perception of features that use dynamic spectral cues.

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Across-Site Threshold Variation in Cochlear Implants: Relation to Speech Recognition

Cited by 58 publications

References 15 publications

Intracochlear Position of Cochlear Implants Determined Using CT Scanning versus Fitting Levels: Higher Threshold Levels at Basal Turn

Intracochlear Position of Cochlear Implants Determined Using CT Scanning versus Fitting Levels: Higher Threshold Levels at Basal Turn

Electrically evoked compound action potentials are different depending on the site of cochlear stimulation

Relationship between multipulse integration and speech recognition with cochlear implants

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