Measurement of Cochlear Implant Electrode Position From Intraoperative Post-insertion Skull Radiographs

Svrakic, Maja; Friedmann, David R.; Berman, Phillip M.; Davis, Adam; Roland, J. Thomas; Svirsky, Mario A.

doi:10.1097/mao.0000000000000852

Cited by 30 publications

(35 citation statements)

References 20 publications

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“…The insertion angle of each electrode was estimated by using intraoperative plain radiograph images of participants’ implanted cochlea (Landsberger et al, 2015; Svrakic et al, 2015) and based on methods described by earlier investigators (Marsh et al, 1993; Cohen et al, 1996; Xu et al, 2000). To evaluate objectively the insertion angles of the intracochlear electrodes in the array, several fixed reference points were used (see Figure 3).…”

Section: Methodsmentioning

confidence: 99%

Pitch Matching between Electrical Stimulation of a Cochlear Implant and Acoustic Stimuli Presented to a Contralateral Ear with Residual Hearing

2017

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Background Cochlear implants (CIs) successfully restore hearing in postlingually deaf adults, but in doing so impose a frequency-position function in the cochlea that may differ from the physiological one. Purpose The CI-imposed frequency-position function is determined by the frequency allocation table programmed into the listener’s speech processor and by the location of the electrode array along the cochlea. To what extent can postlingually deaf CI users successfully adapt to the difference between physiological and CI-imposed frequency-position functions? Research Design We attempt to answer the question by combining behavioral measures of electroacoustic pitch matching (PM) and measures of electrode location within the cochlea. Study Sample The participants in this study were 16 adult CI users with residual hearing who could match the pitch of acoustic pure tones presented to their unimplanted ears to the pitch resulting from stimulation of different CI electrodes. Data Collection and Analysis We obtained data for four to eight apical electrodes from 16 participants with CIs (most of whom were long-term users), and estimated electrode insertion angle for 12 of these participants. PM functions in this group were compared with the two frequency-position functions discussed above. Results Taken together, the findings were consistent with the possibility that adaptation to the frequency-position function imposed by CIs does happen, but it is not always complete. Conclusions Some electrodes continue to be perceived as higher pitched than the acoustic frequencies with which they are associated despite years of listening experience after cochlear implantation.

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Section: Methodsmentioning

confidence: 99%

Pitch Matching between Electrical Stimulation of a Cochlear Implant and Acoustic Stimuli Presented to a Contralateral Ear with Residual Hearing

2017

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“…Angular depth of insertion (aDOI) was measured from the intraoperative radiographs based on earlier described methods [20–22] that have received further validation recently [23]. Differences in aDOI were analyzed using two-way ANOVA, with surgeon and electrode type as the two factors.…”

Section: Patient Population and Methodsmentioning

confidence: 99%

Initial Operative Experience and Short-term Hearing Preservation Results With a Mid-scala Cochlear Implant Electrode Array

Svrakic

Roland²,

McMenomey³

et al. 2016

Otology &Amp; Neurotology

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OBJECTIVE To describe our initial operative experience and hearing preservation results with the Advanced Bionics (AB) Mid Scala Electrode (MSE) STUDY DESIGN Retrospective review. SETTING Tertiary referral center. PATIENTS Sixty-three MSE implants in pediatric and adult patients were compared to age- and gender-matched 1j electrode implants from the same manufacturer. All patients were severe to profoundly deaf. INTERVENTION Cochlear implantation with either the AB 1j electrode or the AB MSE. MAIN OUTCOME MEASURES The MSE and 1j electrode were compared in their angular depth of insertion (aDOI) and pre- to post-operative change in hearing thresholds. Hearing preservation was analyzed as a function of aDOI. Secondary outcome measures included operative time, incidence of abnormal intraoperative impedance and telemetry values, and incidence of postsurgical complications. RESULTS Depth of insertion was similar for both electrodes, but was more consistent for the MSE array and more variable for the 1j array. Patients with MSE electrodes had better hearing preservation. Thresholds shifts at four audiometric frequencies ranging from 250 to 2,000 Hz were 10 dB, 7 dB, 2 dB and 6 dB smaller for the MSE electrode than for the 1j (p<0.05). Hearing preservation at low frequencies was worse with deeper insertion, regardless of array. Secondary outcome measures were similar for both electrodes. CONCLUSIONS The MSE electrode resulted in more consistent insertion depth and somewhat better hearing preservation than the 1j electrode. Differences in other surgical outcome measures were small or unlikely to have a meaningful effect.

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“…Radiology during CI surgery can be used to generate a static view of the electrode or provide a live video stream to guide insertion. CT provides the most detailed information about the orientation of CI electrodes within the cochlea (Kong et al 2012; Sennaroglu et al 2002; Svrakic et al 2015). CI surgery for severe malformations of the inner ear also benefit from novel intraoperative CT approaches (Bloom et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Auditory Brainstem Implant Array Position Varies Widely Among Adult and Pediatric Patients and Is Associated With Perception

et al. 2017

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Objectives The auditory brainstem implant (ABI) provides sound awareness to patients who are ineligible for cochlear implantation. Auditory performance varies widely among similar ABI cohorts. We hypothesize that differences in electrode array position contribute to this variance. Herein, we classify ABI array position based on postoperative imaging and investigate the relationship between position and perception. Design Retrospective review of pediatric and adult ABI users with postoperative computed tomography (CT). To standardize views across subjects, true-axial reformatted series of scans were created using the McRae line. Using multiplanar reconstructions, basion and electrode array tip coordinates and array angles from vertical were measured. From a lateral view, array angles (V) were classified into Types I-IV, and from posterior view, array angles (T) were classified into Types A-D. Array position was further categorized by measuring distance vertical from basion (D1) and lateral from midline (D2). Differences between array classifications were compared with audiometric thresholds, number of active electrodes, and pitch ranking. Results Pediatric (n=4, 2 with revisions) and adult (n=7) ABI subjects were included in this study. Subjects had a wide variety of ABI array angles, but most were aimed superiorly and posteriorly (Type II, n=7) from lateral view and upright or medially tilted from posterior view (Type A, n=6). Mean pediatric distances were 8 – 42% smaller than adults for D1 and D2. In subjects with perceptual data, electrical thresholds and the number of active electrodes differed among classification types. Conclusions In this first study to classify ABI electrode array orientation, array position varied widely. This variability may explain differences in auditory performance.

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Measurement of Cochlear Implant Electrode Position From Intraoperative Post-insertion Skull Radiographs

Cited by 30 publications

References 20 publications

Pitch Matching between Electrical Stimulation of a Cochlear Implant and Acoustic Stimuli Presented to a Contralateral Ear with Residual Hearing

Pitch Matching between Electrical Stimulation of a Cochlear Implant and Acoustic Stimuli Presented to a Contralateral Ear with Residual Hearing

Initial Operative Experience and Short-term Hearing Preservation Results With a Mid-scala Cochlear Implant Electrode Array

Auditory Brainstem Implant Array Position Varies Widely Among Adult and Pediatric Patients and Is Associated With Perception

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