Assessing Cochlear Implant Insertion Angle From an Intraoperative X-ray Using a Rotating 3D Helical Scala Tympani Model

Giardina, Christopher K.; Canfarotta, Michael W; Thompson, Nicholas J; Fitzpatrick, Douglas C.; Hodge, Sarah E.; Baker, Jennifer L.; O’Connell, Brendan P.

doi:10.1097/mao.0000000000002638

Cited by 9 publications

(11 citation statements)

References 36 publications

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“…The intraoperative x-ray was reviewed for the additional standard array subjects, and AID was determined using a rotating helical scala tympani model. 29 This validated algorithm has demonstrated accuracy within 10 of computed tomography, regardless of deviation from cochlear view. Angular insertion depth was used to derive the cochlear place frequency based on the average spiral ganglion (SG) map, as described by Stakhovskaya et al 30 Frequency-to-place mismatch was determined by comparing the center frequency of individual electrode contacts in the familiar, everyday map at each interval to the corresponding place frequency on the SG map.…”

Section: Determination Of Frequency-to-place Mismatchmentioning

confidence: 88%

Long‐Term Influence of Electrode Array Length on Speech Recognition in Cochlear Implant Users

et al. 2020

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Objectives/Hypothesis: Results from a prospective trial demonstrated better speech recognition for cochlear implant (CI) recipients implanted with a long lateral wall electrode array compared to subjects with a short array after 1 year of listening experience. As short array recipients may require an extended adaptation period, this study investigated whether differences in speech recognition continued through 4 years of CI use. Study Design: Long-term follow-up of a prospective randomized trial. Methods: Subjects were randomized to receive a MED-EL medium (24 mm) or standard (31.5 mm) array. Linear mixed models compared speech recognition between cohorts with word recognition in quiet and sentence recognition in noise at 1, 3, 6, 12, 24, and 48 months postactivation. Postoperative imaging and electric frequency filters were reviewed to assess the influence of frequency-to-place mismatch and angular separation between neighboring contacts, a metric associated with peripheral spectral selectivity. Results: Long (31.5 mm) array recipients demonstrated superior speech recognition out to 4 years postactivation. There was a significant effect of angular separation between contacts, with more closely spaced contacts associated with poorer speech recognition. There was no significant effect of mismatch, yet this may have been obscured by changes in frequency filters over time. Conclusions: Conventional MED-EL CI recipients implanted with 31.5-mm arrays experience better speech recognition than 24-mm array recipients, initially and with long-term listening experience. The benefit conferred by longer arrays in the present cohort can be partially attributed to more widely spaced electrode contacts, presumably a result of reduced channel interaction.

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Section: Determination Of Frequency-to-place Mismatchmentioning

confidence: 88%

Long‐Term Influence of Electrode Array Length on Speech Recognition in Cochlear Implant Users

et al. 2020

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“…An intraoperative X-ray was obtained after electrode array insertion. A custom MATLAB script used the intraoperative X-ray to determine the angular insertion depth of the most apical electrode contact for each subject ( Giardina et al., 2020 ), which ranged from 549° to 710°, with a mean of 636° ( SD = 43°).…”

Section: Methodsmentioning

confidence: 99%

Cochlear Implantation in Cases of Asymmetric Hearing Loss: Subjective Benefit, Word Recognition, and Spatial Hearing

et al. 2020

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A prospective clinical trial evaluated the effectiveness of cochlear implantation in adults with asymmetric hearing loss (AHL). Twenty subjects with mild-to-moderate hearing loss in the better ear and moderate-to-profound hearing loss in the poorer ear underwent cochlear implantation of the poorer hearing ear. Subjects were evaluated preoperatively and at 1, 3, 6, 9, and 12 months post-activation. Preoperative performance was evaluated unaided, with traditional hearing aids (HAs) or with a bone-conduction HA. Post-activation performance was evaluated with the cochlear implant (CI) alone or in combination with a contralateral HA (bimodal). Test measures included subjective benefit, word recognition, and spatial hearing (i.e., localization and masked sentence recognition). Significant subjective benefit was reported as early as the 1-month interval, indicating better performance with the CI compared with the preferred preoperative condition. Aided word recognition with the CI alone was significantly improved at the 1-month interval compared with preoperative performance with an HA and continued to improve through the 12-month interval. Subjects demonstrated early, significant improvements in the bimodal condition on the spatial hearing tasks compared with baseline preoperative performance tested unaided. The magnitude of the benefit was reduced for subjects with AHL when compared with published data on CI users with normal hearing in the contralateral ear; this finding may reflect significant differences in age at implantation and hearing sensitivity across cohorts.

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“…The AID of the most apical electrode contact was measured with intraoperative x-ray using a rotating helical scala tympani model, which has been previously described and validated against CT imaging (Giardina et al 2020). Briefly, this method uses a scalable, rotatable 3-dimensional model of the scala tympani to estimate AID from an x-ray obtained at an unknown acquisition angle (Fig.…”

Section: Measurement Of Angular Insertion Depthmentioning

confidence: 99%

Relationship Between Electrocochleography, Angular Insertion Depth, and Cochlear Implant Speech Perception Outcomes

et al. 2020

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Objectives: Electrocochleography (ECochG), obtained before the insertion of a cochlear implant (CI) array, provides a measure of residual cochlear function that accounts for a substantial portion of variability in postoperative speech perception outcomes in adults. It is postulated that subsequent surgical factors represent independent sources of variance in outcomes. Prior work has demonstrated a positive correlation between angular insertion depth (AID) of straight arrays and speech perception under the CI-alone condition, with an inverse relationship observed for precurved arrays. The purpose of the present study was to determine the combined effects of ECochG, AID, and array design on speech perception outcomes. Design: Participants were 50 postlingually deafened adult CI recipients who received one of three straight arrays (MED-EL Flex24, MED-EL Flex28, and MED-EL Standard) and two precurved arrays (Cochlear Contour Advance and Advanced Bionics HiFocus Mid-Scala). Residual cochlear function was determined by the intraoperative ECochG total response (TR) measured before array insertion, which is the sum of magnitudes of spectral components in response to tones of different stimulus frequencies across the speech spectrum. The AID was then determined with postoperative imaging. Multiple linear regression was used to predict consonant-nucleus-consonant (CNC) word recognition in the CI-alone condition at 6 months postactivation based on AID, TR, and array design. Results: Forty-one participants received a straight array and nine received a precurved array. The AID of the most apical electrode contact ranged from 341° to 696°. The TR measured by ECochG accounted for 43% of variance in speech perception outcomes (p < 0.001). A regression model predicting CNC word scores with the TR tended to underestimate the performance for precurved arrays and deeply inserted straight arrays, and to overestimate the performance for straight arrays with shallower insertions. When combined in a multivariate linear regression, the TR, AID, and array design accounted for 72% of variability in speech perception outcomes (p < 0.001). Conclusions: A model of speech perception outcomes that incorporates TR, AID, and array design represents an improvement over a model based on TR alone. The success of this model shows that peripheral factors including cochlear health and electrode placement may play a predominant role in speech perception with CIs.

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Assessing Cochlear Implant Insertion Angle From an Intraoperative X-ray Using a Rotating 3D Helical Scala Tympani Model

Cited by 9 publications

References 36 publications

Long‐Term Influence of Electrode Array Length on Speech Recognition in Cochlear Implant Users

Long‐Term Influence of Electrode Array Length on Speech Recognition in Cochlear Implant Users

Cochlear Implantation in Cases of Asymmetric Hearing Loss: Subjective Benefit, Word Recognition, and Spatial Hearing

Relationship Between Electrocochleography, Angular Insertion Depth, and Cochlear Implant Speech Perception Outcomes

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