Intraoperative Neural Response Telemetry Research Articles

Intraoperative Neural Response Telemetry and Auditory Outcomes in Pediatric Cochlear Implantation.

To evaluate the relationship between intraoperative neural response telemetry (NRT) and postoperative auditory testing outcomes in children. Retrospective study. Tertiary-care academic center. Children who underwent cochlear implantation using the Cochlear Corporation device between 2010 and 2019 were included. Associations of average NRT and the slope of amplitude with postoperative auditory outcomes including functional auditory measure Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS), and speech perception testing (consonant-nucleus-consonant [CNC], Pediatric AzBio [BABY BIO], Hearing In Noise Test [HINT], and Northwestern University Children's Perception of Speech [NU-CHIPS]), measured between 6 and 57 months after implantation, were assessed using Spearman's rank correlation (ρ). Thirty-eight patients (19 female, 19 male) and 54 ears were included. The median age of implantation was 20.6 months (range 9.6 months to 10.6 years). Eight (21%) children had neurologic disorders such as stroke, epilepsy, cerebral palsy, and other causes. Thirteen (34%) children had connexin mutations. Average NRT was not significantly correlated with postoperative auditory outcomes (IT-MAIS [ρ = -0.08, p = .74], CNC [ρ = 0.19, p = .32], BABY BIO [ρ = 0.21, p = .29], HINT [ρ = 0.05, p = .83])and NU-CHIPS (ρ = 0.21, p = .28). The average slopes of amplitude and comfort level were not strongly correlated with any auditory outcomes (p > .05). Intraoperative NRT was not correlated with any postoperative functional auditory outcomes. Patient counseling should include discussions that a subpar intraoperative cochlear response does not preclude favorable speech and auditory outcomes.

Comparison of Intraoperative Neural Response Telemetry Results and Postoperative Neural Response Telemetry Results in Case of Children with Congenital Bilateral Severe to Profound Sensorineural Hearing Loss Undergoing Single Sided Cochlear Implantation.

This study is designed to compare the Intra Operative Neural Response Telemetry (NRT) results with Post-Operative NRT results of the cochlear implanted children, to assess the importance of Intra Operative NRT thresholds in device activation and/or switch on of the audio processor and to evaluate the importance of Intra and post operative AutoNRT results in predicting behavioural thresholds during mapping of prelingual Cochlear Implanted children. A total of thirty (30) children (16 boys, 14 girls) with congenital Bilateral (B/L) severe to profound Sensorineural hearing loss (SNHL) were included in this study. Children between the age range of 12 to 60 months were participated in this study. All the participants were implanted with Nucleus 24 cochlear implant system. In each patient, the intra operative NRT-thresholds were measured for all 22 active electrodes. Then Intra Operative NRT thresholds were correlated with Post-Operative NRT thresholds at the time of switch on and the behavioural map after six months of switch on of the device (Audio Processor). There is a significant enhancement observed in thresholds of postoperative NRT responses which were raised or absent during intraoperative session. There is a gain in NRT thresholds marked after 6 months of postoperative follow up in comparison with first measurement at the time of Switch On of the device but the change not that significant. During postoperative mapping, there was a significant positive correlation noticed between neural response telemetry level measurements and behavioural threshold level. Absent or elevated NRT responses during intraoperative testing for some electrodes especially basal electrodes does not mean that electrode is out of order or outside the cochlea, because an improvement in NRT thresholds usually occurs postoperatively. In case of children with congenital B/L severe to profound SNHL, the NRT values have a very useful role in predicting the behavioural thresholds. Combination of NRT values with behavioural thresholds and observations of Auditory Verbal Therapist can help in providing best suitable Map to the recipient. The online version contains supplementary material available at 10.1007/s12070-022-03284-x.

Utility of intraoperative neural response telemetry in pediatric cochlear implants.

The objective of this study is to evaluate the relationship between intraoperative neural response telemetry (NRT) and postoperative Threshold (T) and Comfort (C) levels and their correlation over time after cochlear implantation (CI). A retrospective chart review was conducted of patients less than 18 years of age who had CI with a Cochlear™ device and NRT at an academic center from 2010 to 2019. Data collected included demographics, extrapolated NRT threshold (tNRT) and slope of amplitude for electrodes 1, 6/7, 11/12, 16, and 22, and postoperative T and C levels at initial activation and 1 month, 3 months, and 1 year post-activation. Associations between T and C levels and slope of amplitude or tNRT were assessed using Spearman's rank correlation. 39 patients (65 CIs) were included. Intraoperative tNRT correlated strongly with T and C levels at 1 month, 3 months, and 1 year post-activation on nearly all electrodes. Electrodes 6/7 and 11/12at 3 months and electrodes 6/7at 1 year did not correlate with T and C levels. There was no significant relationship between the slope of amplitude for nearly all electrodes and the T or C levels post-activation. NRT is invaluable in children, with significant correlation found between tNRT and T and C levels over time on nearly all electrodes. There are changes in T and C levels in electrodes 6/7 and 11/12 over time, and close surveillance is beneficial to tailor programming as needed.

Remote Intraoperative Neural Response Telemetry: Technique and Results in Cochlear Implant Surgery.

Present results with remote intraoperative neural response telemetry (NRT) during cochlear implantation (CI) and its usefulness in overcoming the inefficiency of in person NRT. Case series. Tertiary academic otology practice. All patients undergoing primary or revision CI, both adult and pediatric, were enrolled. Remote intraoperative NRT performed by audiologists using a desktop computer to control a laptop in the operating room. Testing was performed over the hospital network using commercially available software. A single system was used to test all three FDA-approved manufacturers' devices. Success rate and time savings of remote NRT. Out of 254 procedures, 252 (99.2%) underwent successful remote NRT. In two procedures (0.7%), remote testing was unsuccessful, and required in-person testing to address technical issues.Both failed attempts were due to hardware failure (OR laptop or headpiece problems). There was no relation between success of the procedure and patient/surgical factors such as difficult anatomy, or the approach used for inner ear access. The audiologist time saved using this approach was considerable when compared with in-person testing. Remote intraoperative NRT testing during cochlear implantation can be performed effectively using standard hardware and remote-control software. Especially important during the Covid-19 pandemic, such a procedure can reduce in-person contacts, and limit the number of individuals in the operating room. Remote testing can provide additional flexibility and efficiency in audiologist schedules.

Round window versus conventional bony cochleostomy technique in pediatric cochlear implantation; A Randomized controlled double blinded trial.

<p><strong>Background:</strong> Objective of the study was to investigate the outcomes of cochlear implantation when done via two different techniques namely, the round window or the bony cochleostomy.</p><p><strong>Methods:</strong> A single-center, double-blinded randomized controlled trial including forty prelingual, bilateral severe to profoundly deaf children less than six years from the year 2014 to 2016 in a tertiary referral center in India were randomly allocated to round window and bony cochleostomy group. Our primary outcome measures were intraoperative neural response telemetry levels, behavioral threshold (t) and comfortable (c) loudness levels. The secondary subjective outcomes were measured via the category of auditory performance (CAP) and the meaningful auditory integration scale (MAIS) score. The cases were followed up for 9 months.</p><p><strong>Results:</strong> Intra-operative, electrically evoked compound action potentials (ECAP) showed comparable mean thresholds for both the techniques except intermediate electrodes (p~0.04) showed lower values for the round window. Similarly, a lower threshold (p~0.03) and comfortable mean current levels (p~0.03) were noticed for the round window group at 6 months post-implantation. Secondary speech perception outcome scores measured via category of auditory performance (CAP) and MAIS score were comparable. </p><p><strong>Conclusions:</strong> The round window insertion technique has physiological benefit as compared to the bony cochleostomy as evidenced by better stimulation levels in the intermediate electrodes and lower mean threshold and comfortable levels in the round window with more beneficial peri-modiolar position of electrode arrays. However, comparable speech perception outcomes revealed no clinical benefit in the cochlear implant performance depending on the technique of electrode insertion. </p>

Cochlear implantation in auditory neuropathy spectrum disorders: role of transtympanic electrically evoked auditory brainstem responses and serial neural response telemetry.

To evaluate the utility of pre-operative transtympanic electrically evoked auditory brainstem responses and post-operative neural response telemetry in auditory neuropathy spectrum disorder patients. Four auditory neuropathy spectrum disorder patients who had undergone cochlear implantation and used it for more than one year were studied. All four patients underwent pre-operative transtympanic electrically evoked auditory brainstem response testing, intra-operative and post-operative (at 3, 6 and 12 months after switch-on) neural response telemetry, and out-patient cochlear implant electrically evoked auditory brainstem response testing (at 12 months). Patients with better waveforms on transtympanic electrically evoked auditory brainstem response testing showed superior performance after one year of implant use. Neural response telemetry and electrically evoked auditory brainstem response measures improved in all patients. Inferences related to cochlear implantation outcomes can be based on the waveform of transtympanic electrically evoked auditory brainstem responses. Robust transtympanic electrically evoked auditory brainstem responses suggest better performance. Improvements in electrically evoked auditory brainstem responses and neural response telemetry over time indicate that electrical stimulation is favourable in auditory neuropathy spectrum disorder patients. These measures provide an objective way to monitor changes and progress in auditory pathways following cochlear implantation.

A study on relationship between Neural Response Telemetry and behavioural Threshold/Comfort levels in children with cochlear implant

BackgroundOur study was a prospective, non-randomised, single tertiary care centre study involving 50 children below 10 years, all implanted with Nucleus 24™ cochlear implants to find the relationship between intra-operative NRT (Neural Response Telemetry) values and post-operatively behaviourally obtained Threshold (T) and Comfort (C) levels. MethodsNRT threshold values were obtained intra-operatively by using Custom Sound EP Software V 4.4™ (Cochlear Corporation). At switch-on after three weeks, behavioural T and C levels were measured based on behavioural responses given by patients using Custom Sound Version 4.4 software™ (Cochlear Corporation). NRT values were also measured at switch-on, 2 months, 3 months and 6 months. ResultsIntra-operative NRT levels (187.96 ± 12.48) were higher than both T (160.63 ± 22.69) and C (181.21 ± 22.41) levels obtained after 3 weeks. In addition, there was a weak correlation of NRT values with T (P value: 0.05, r = 0.391) and C (P value: 0.05, r = 0.390) levels. ConclusionNRT is a quick and non-invasive tool to confirm cochlear implant integrity. There is a weak correlation of NRT values with both T and C levels and therefore, intra-operative NRT is a weak predictor for setting both T and C levels at switch-on.

Is the spread of excitation width correlated to the speech recognition in cochlear implant users?

To assess whether there is an interference of the spread of excitation (SOE) on speech recognition. Retrospective cross-sectional study, approved by the institution's ethics committee (CAAE03409212.8.0000.0068). Adult patients with intraoperative neural response telemetry (NRT) performed on electrodes 6, 11 and 16 implanted with Cochlear Ltd (Sydney, Australia) devices were selected. Patients with partial array insertion, pre-lingual hearing loss, deafness etiology due to and CI experience less than 12months were excluded. SOE was recorded at 10 current units above the NRT threshold (tNRT) and its width in millimeters was collected at point 0.75 of the function. Speech recognition test was 25-recorded monosyllables list, presented at 65dBHL at 0° azimuth in a sound treated booth. The analysis was divided into groups by electrode array type, regarding the tNRT, SOE width, SOE's peak amplitude and electrode peak. A 126 SOE measurements of the 3 tested electrodes were obtained from 43 patients. Patients with straight array had significantly wider SOE, greater peak amplitude at electrode 6 and higher tNRTs. In the perimodiolar array, there was a negative correlation between SOE and monosyllables recognition at electrodes 6 and 11, and in the combined average of the three electrodes, with a significant difference in electrode 11. Sixty-six percent of the SOE measurements had their peak shifted to adjacent electrodes. It was observed, in perimodiolar array, the greater the dispersion of electrical current, the worse the speech recognition, especially in the medial electrode.

Accuracy of intraoperative electrophysiological testing in confirming correct cochlear implant electrode positions

Objective: To investigate the accuracy of intraoperative electrophysiological studies in detecting incorrectly positioned electrodes in cochlear implant surgery.Study design: A retrospective chart review.Setting: Tertiary referral centre.Patients: In total, 104 consecutive patients with a mean age of 5 years underwent cochlear implant surgery at our centre between January 2012 and December 2013. All patients were implanted with Cochlear Nucleus Freedom implants.Method: A retrospective study to compare intraoperative neural response telemetry (NRT), impedance and electrode position using Stenver’s transorbital plain X-ray view.Results: Intraoperative electrophysiological tests for patients with Cochlear Nucleus Freedom implants showed 97% sensitivity and 100% specificity compared with postoperative X-ray imaging.Conclusion: NRT results for the position of cochlear implants were very accurate when checked by X-ray imaging showing that this technique is sufficient in most cases. Stenver’s plain X-ray view is needed in complicated cases with abnormal NRT testing or difficult electrode insertion.

Comparison of Neural Response Telemetry (NRT) results of cochlear implanted children in view of pre-operative Auditory Brainstem Response (ABR)

To compare the Neural Response Telemetry (NRT) results of the cochlear implanted children who showed wave 5 and who could not, in preimplantation ABR. 24 children (11 boys, 13 girls) with bilateral profound sensorineural hearing loss participated in this study. Age of children ranged between 13 and 60 months (mean 30 months). All participated children were implanted with Cochlear® Nucleus brand devices. In preoperative ABR evaluation with click stimulus in 100 dBnHL intensity level, 9 children showed wave V and 15 children did not. We compared intraoperative NRT results of 1st, 6th, 11th, 16th and 22nd electrodes, those were selected from 22 electrodes, of the two groups. There was no statistically significant difference between the children who showed wave V and who did not in preoperative ABR, when compared the intraoperative NRT results of 1st, 6th, 11th, 16th and 22nd electrodes (p>0,05). intraoperative NRT was obtained in all the implanted children with bilateral profound sensorineural hearing loss, even if they received wave V or not in preoperative ABR. There was no difference between any of the parameters of the test results of the two groups. Normal NRT results can be achievable when there is no wave V in preoperative ABR.

Application of “banana cochleostomy” and looped electrode insertion for cochlear implantation in children with common cavity malformation and cystic forms of cochlear hypoplasia

ObjectivesPatients with profound hearing loss due to inner ear malformations may benefit from cochlear implantation; however, the surgery may present a substantial problem for the cochlear implant surgeon due to anatomical variations.The authors describe a new surgical and technical advancement for implantation in patients with small inner ear cavities that make the surgery easier and safer. On the basis of experience involving five consecutive surgeries performed in four patients with inner ear malformations, we present the advantages and application possibilities of the technique. MethodsThe technique does not change the surgical approach in general; however, modification of the cochleostomy shape and looping of the cochlear implant electrode enables safe advancement of the electrode with optimal positioning in the cavity. Additionally, these modifications protect against the insertion of the electrode into the internal auditory canal minimizing the risk of gushing and extracochlear stimulation. ResultsThe present technique has been used in five cases of cystic implantable inner ear spaces in three independent institutions by different surgeons. It has proven to be a reliable, relatively easy and safe procedure performed with very good anatomic and initially functional effects (positive intraoperative neural response telemetry measurements). ConclusionsWe hope that utilization of the “banana cochleostomy” and insertion of the looped cochlear implant electrode in the implantable cystic spaces of children with malformed inner ears will facilitate and simplify the surgical technique in this difficult procedure and additionally, in revision surgical cases. To our knowledge, the looped insertion and banana-shaped cochleostomy have not been reported previously.

Use of Neural Response Telemetry for Pediatric Cochlear Implants: Current Practice

Evaluate usage trends of neural response telemetry (NRT) in cochlear implant centers across the nation and assess reported benefits of intraoperative NRT for pediatric cochlear implant recipients. Survey. All US cochlear implant centers (n = 110). A 15-question multiple-choice survey was distributed electronically to all centers. The survey captured demographic information of all centers, practice patterns surrounding the use of NRT, and the extent to which intraoperative NRT is of benefit. Thirty-two invited participants (29%) completed the survey. A majority of participants reported practicing in an academic center (66%), followed by a hospital setting (19%) and private practice (16%). Seventy-two percent of survey participants reported using NRT for pediatric cochlear implant recipients. Sixty-three percent felt it improved the ability to program at initial activation, and 50% of participants felt that NRT improves satisfaction at initial activation. This study suggests that a majority of surgeons use intraoperative NRT for pediatric cochlear implantation as an additional measure to ensure appropriate electrode placement and improve device activation. Larger studies are needed to better establish the relationship between intraoperative NRT and postoperative outcomes and justify the additional costs associated with intraoperative NRT.

Cochlear implantation in Mondini’s deformity: could the straight electrode array with length of 31 mm be fully inserted?

Conclusions: The straight electrode array with length of 31 mm can be fully inserted using round window insertion in cochlear implantation with Mondini’s deformity. It is a safe and effective process, but also a challenging task of the full implantation in children with Mondini’s deformity.Objective: The aim of this study is to discuss whether the straight electrode array with a length of 31 mm could be fully inserted in cochlear implantation with Mondini’s deformity.Methods: A chart review of 30 patients undergoing cochlear implantation with Mondini’s deformity using the electrode array with length of 31 mm was undertaken from January 2012 and December 2015 in Anhui Provincial Hospital.Results: Full insertion of the straight electrode array with length of 31 mm were performed successfully in all patients with Mondini’s deformity using round window insertion. Resistance was not encountered while introducing the electrodes. Ten of 30 patients had cerebrospinal fluid drainage during cochlear implantation. Cerebrospinal fluid drainage was controlled with small pieces of temporalis fascia packing round window in all patients. Intra-operative neural response telemetry was performed in all patients, and results were good. The result of X-ray showed proper placement of the cochlear implant electrode array. During surgery, no patients had experienced any immediate or delayed post-operative complications such as wound infection, intracranial complication, extrusion, or migration of the implant during an average follow-up period of 6–36 months.

Electrophysiological Detection of Scalar-Changing Perimodiolar Cochlear Electrode Arrays: A Six-Month Follow-Up Study

The position of the cochlear electrode array within the scala tympani is essential for optimal hearing benefit. An intraoperative neural response telemetry ratio (NRT ratio; a threshold ratio of pairs of apical and basal electrodes) has been established, which can provide information about the intracochlear electrode array position. Out of a previous collective of 85 patients, the 6-month follow-up electrophysiological NRT data of 37 patients have been included in this study. Comparing the intraoperatively estimated NRT ratio with the 6-month follow-up NRT ratio, it remained unchanged intraindividually in 92% of cases. Within this group the NRT ratio and the intracochlear position of the electrode array matched in all cases. There were two newly occurring mismatches and one new match was observed. After a period of 6 months the NRT ratio remained unchanged in most cases and showed a good correlation with the intracochlear position of the electrode array.

Electrophysiological Detection of Intracochlear Scalar Changing Perimodiolar Cochlear Implant Electrodes: A Blinded Study.

To investigate whether a previous established neural response telemetry (NRT) ratio corresponds with the scalar position of the CI electrode. Retrospective blinded controlled study. Tertiary referral center. The electrophysiological data sets of 85 patients with measured intraoperative NRTs were evaluated. All patients were implanted with the same CI system. Using a flat panel tomography system, the position of the electrode array was confirmed radiologically. The radiological results were blindly compared with the intraoperatively obtained electrophysiological data (NRT ratio) and statistically evaluated. In a second step, irregularities between the NRT ratios and the radiologically confirmed electrode positions were determined and the entire study material was investigated deeper. Correlation of the NRT ratio with the intracochlear position of the CI electrode. By electrophysiological evaluation only, 69 patients were detected without a scalar change at first. In 16 patients, a scalar change was probable. A significant correlation between the radiological results and the NRT ratios was found. Secondly, additional patient characteristics were identified which influences the electrode's position. Excluding those patients, the selectivity and specificity of the NRT ratio could be increased to a higher level. Evidenced by a blinded group of patients, we are able to show that the electrode array position within the cochlea could be predicted using the NRT ratio.

Does pediatric cochlear implant insertion technique affect intraoperative neural response telemetry thresholds?

ObjectiveRecent reports of mostly adult patients suggest round window insertion is less traumatic than cochleostomy for cochlear implantation (CI), while other reports have indicated that curved electrode arrays lower the neural response telemetry (NRT) threshold and consume less power. We aimed to compare the intraoperative neural response telemetry (NRT) thresholds in children receiving cochlear implants through a cochleostomy (COCH) vs. a round window (RW) approach, as well as patients receiving a curved array vs. a straight one. DesignA direct case-cohort comparison of NRT in pediatric CI recipients at two large tertiary pediatric hospitals from 2008 through 2014 was done. Univariate Mann–Whitney analyses and one-wayANOVA were performed to compare average NRT in RW vs. COCH insertion, and curved vs. straight electrodes. Multivariate regression was performed to control for age and pre- vs. postlingual patient status. ResultsOverall, 236 children were included, between January 2008 and October 2014 at two large tertiary referral medical centers. A total of 52 patients received a RW insertion and 184 received a cochleostomy. There was no statistically significant difference between RW insertion (187.9±18.7) and COCH (183.4±17.1) (p=0.125). The patients were divided into four categories: RW insertion with curved electrode (175.0±11.2), RW with straight electrode (192.1±18.8), COCH with curved electrode (182.2±16.7), and COCH with straight electrode (193.0±20.8). The lowest NRT current thresholds were achieved with curved electrode array insertions through the RW (p=0.001). Multivariate regression analysis revealed the following parameters were not independently associated with differences in NRT responses: RWI vs. COCH (p=0.12) and pre- vs. postlingual (p=0.18). The difference in NRT levels between curved electrode arrays and straight was shown to be statistically significant (p=0.00075). ConclusionsWhen controlling for insertion technique or pre- vs. postlingual hearing loss, the curved electrode array correlates with lower NRT thresholds. Although studies to examine functional language performance of these recipients are pending, initial results of this multi-institutional trial suggest that curved electrodes indeed result in lower NRT levels, particularly when inserted through the RW.

Neural Response Telemetry Thresholds in Patients with Cochlear Nerve Canal Stenosis.

To explore neural response telemetry (NRT) thresholds in patients with stenotic versus normal cochlear nerve canals. Case series with chart review. Tertiary referral center. Thirty pediatric patients with profound sensorineural hearing loss in at least 1 ear and no benefit from amplification underwent computed tomography imaging of the temporal bones. They were divided into 3 groups according to the diameter of the cochlear nerve canal: group A, <1.5 mm; group B, 1.5 to 1.7 mm; group C, 1.8 to 2.1 mm. All patients underwent cochlear implantation with full insertion of all electrodes. NRT was performed both intraoperatively and 6 months postoperatively in all patients; thresholds of electrodes 1, 11, and 22 were compared. Per analysis of variance, intraoperative and 6-month postoperative NRT thresholds were both significantly different among groups A, B, and C at electrodes 1 and 22 but not at electrode 11. On intergroup analysis, group A showed statistically higher thresholds than those of groups B and C; however, no difference was found between groups B and C. Cochlear nerve canal stenosis, defined as a canal diameter <1.5 mm, is associated with significantly increased NRT thresholds, which may play a role in postimplant performance.

Facial nerve stimulation associated with cochlear implant use following temporal bone fractures

ObjectiveTo describe the incidence and management of patients with facial nerve stimulation (FNS) associated with cochlear implant (CI) use in the setting of a prior temporal bone fracture. PatientsOne adult CI recipient is reported who experienced implant associated FNS with a history of a temporal bone fracture. Additionally, a literature search was performed to identify similar patients from previous descriptions of CI related FNS. Main outcome measuresPresence of FNS after implantation and ability to modify implant programming to avoid FNS. ResultsThe patient in the present report experienced FNS for middle and basal electrodes during intraoperative neural response telemetry (NRT) in the absence of any surgical exposure or manipulation of the facial nerve. FNS was absent during device activation, but it recurred during follow-up programming sessions. However, additional programming has prevented further FNS during regular implant use. Four other patients with FNS after temporal bone fracture were identified from the literature, and the present case represents the one of two cases in which reprogramming allowed for implant use without FNS. ConclusionsCI associated FNS is uncommon in patients with a history of a temporal bone fracture, but it is likely that fracture lines provide a lower impedance pathway to the adjacent facial nerve and thus reduce the threshold for FNS. The present report suggests that, in the setting of a prior temporal bone fracture, NRT is not always a reliable predictor of FNS during implant use, and programming changes can help to mitigate FNS when it occurs.

Electrode array misplacement into the superior semicircular canal: As a rare complication of cochlear implantation

ObjectiveTo report electrode array misplacement into the superior semicircular canal occurring as an rare complication of cochlear implantation through round window insertion, and to explore the causative association between electrode array misplacement and cochlear implantation surgical techniques. MethodsA chart review of the electrode array misplacement into the superior semicircular canal and their management in 695 patients undergoing cochlear implantation was undertaken from January 2003 and January 2014 in Anhui Provincial Hospital. ResultsThere were two children of electrode array misplacement into the superior semicircular canal complication, and the rate was 0.28%. ConclusionsElectrode array misplacement into the superior semicircular canal associated with cochlear implantation is rare. Surgeons should be aware of that the smaller round window maybe the reason of electrode array misplacement through round window insertion. Intra-operative neural response telemetry and X-ray can alert the surgeon the problem with the array's misplacement, which can be identified by postoperative CT.

Intraoperative Neural Response Telemetry and Neural Recovery Function: a Comparative Study between Adults and Children.

Introduction Neural response telemetry (NRT) is a method of capturing the action potential of the distal portion of the auditory nerve in cochlear implant (CI) users, using the CI itself to elicit and record the answers. In addition, it can also measure the recovery function of the auditory nerve (REC), that is, the refractory properties of the nerve. It is not clear in the literature whether the responses from adults are the same as those from children. Objective To compare the results of NRT and REC between adults and children undergoing CI surgery. Methods Cross-sectional, descriptive, and retrospective study of the results of NRT and REC for patients undergoing IC at our service. The NRT is assessed by the level of amplitude (microvolts) and REC as a function of three parameters: A (saturation level, in microvolts), t0 (absolute refractory period, in seconds), and tau (curve of the model function), measured in three electrodes (apical, medial, and basal). Results Fifty-two patients were evaluated with intraoperative NRT (26 adults and 26 children), and 24 with REC (12 adults and 12 children). No statistically significant difference was found between intraoperative responses of adults and children for NRT or for REC's three parameters, except for parameter A of the basal electrode. Conclusion The results of intraoperative NRT and REC were not different between adults and children, except for parameter A of the basal electrode.