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Objectives: Bilateral cochlear implants (CI) are the standard treatment for bilaterally deaf children, but it is unclear how much the second CI can be delayed in sequential bilateral CI. We investigated the performances of sequential CI to answer this question. Study Design: Retrospective case series review. Setting: Tertiary referral center. Methods: We studied a cohort of congenitally deaf children (n = 73) who underwent sequential CI without any inner ear anomaly or combined disabilities. Hearing threshold levels and speech perception were evaluated by aided pure tone audiometry and Asan-Samsung Korean word recognition test. The scores were analyzed by the ages at surgery and compared among the different age groups. Results: When the second CI was performed before 3.5 years (the optimal period for the first CI), the second CI scores (96.9%) were comparable to the first CI scores. Although the first CI scores were ≥80% when the first CI was implanted before the age of 7 years, the second CI scores were ≥80% when the second CI was implanted before the age of 12-13 years. The hearing threshold levels were not different regardless of the ages and between the first and second CIs. Conclusion: Our cohort demonstrated that the second CI showed comparable results to the first CI when implanted before 3.5 years, suggesting that optimal periods for the first CI and the second CI are same. However, the sensitive period (12-13 years) for the second CI with good scores (≥80%) was much longer than that (7 years) of the first CI, suggesting that the first CI prolongs the sensitive period for the second CI. The second CI should be implanted early, but considered even at a later age. [ABSTRACT FROM AUTHOR]

To analyze characteristics and propose mechanisms of FNS (Facial Nerve Stimulation) in cochlear implant surgeries. Thirty-two ears from 29 patients with FNS were evaluated from among 1151 ears which received a cochlear implant between April 1999 and July 2016. Locations of electrodes involved with FNS, presence and types of cochlear anomalies, presence of cochleo-facial dehiscence, and the current levels were analyzed. The current levels were compared to those of age- and sex-matched control group. Incidence of FNS was 2.8% (32/1151), and it was higher in ears with a cochlear anomaly (6.4%, 25/391) than in those without an anomaly (0.9%, 7/760). Patients without an anomaly showed two types of FNS: FNS at apical electrodes related to cochleo-facial dehiscence with low current levels, and FNS at basal electrodes with high current levels and partial insertion of electrodes. Patients with an anomaly showed a third type of FNS at most electrodes with high current levels, which was the most common type in patients with a common cavity or narrowing of the bony cochlear nerve canal. Facial nerve stimulation occurred at various current levels and locations of electrodes by different mechanisms related to incomplete insertion of electrodes, cochleo-facial dehiscence, and types of cochlear anomalies. Our findings might provide insight for preventing facial nerve stimulation when performing cochlear implant surgeries. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the diameter of bony cochlear nerve canal (BCNC) as a prog-nostic value of cochlear implantation in children. Subjects and Methods: We collected 327 prelingual deaf children who received coch-lear implantation before five years of age. We reviewed the preoperative temporal bone com-puted tomography (TBCT) and divided into three groups according to the diameter of BCNC: narrow BCNC (Group 1), normal (Group 2), and other anomalies (Group 3). Narrow BCNC group was divided into three groups according to the degree of stenosis: complete stenosis (Group A), less than 0.8mm (Group B), and from 0.8mm to 1.4mm (Group C). For each group, postoperative auditory performances are analyzed according to the diameter of BCNC using the Mann-Whitney U-test. Results: Among the 327 children, 38 children (11.6%) were found to have narrow BCNC (Group 1), 185 children (56.6%) had normal BCNC and inner ear structure (Group 2), and 104 children (31.8%) had other anomalies (Group 3). Group 1 showed less significant improvement in Category of Audiological Performance (CAP) score compared with Group 2 and Group 3. Open-set monosyllabic words test was more deficient in Group 1 than Group 2 and Group 3. Open-set sentence identification test was lower in Group 1 than Group 2 and Group 3. Among the 38 children with narrow BCNC (Group 1), five children had complete stenotic BCNC (Group A), 21 children had BCNC less than 0.8mm (Group B), and 12 children's BCNC di-ameter were from 0.8mm to 1.4mm (Group C). The CAP score of Group A was poorer than the Group B and Group C, and CAP score of Group B was also lower than Group C. Conclusion: The improvement of auditory performance was limited in children with nar-row BCNC and the narrower the BCNC, the more severe the limitation. However, gradual im-provement can be expected. Through these, even children with narrow BCNC need early coch-lear implantation and rehabilitation. This study evidenced the speech perception performance in children having BCNC, which are useful information for preoperative counseling of CI candi-dates and family. [ABSTRACT FROM AUTHOR]

Objectives: Bimodal amplification shows better cognition of sounds through the improvement of head shadow effect, binaural squelch effect and binaural summation effect. In patients received unilateral cochlear implantation, the impact of hearing aids in the contralateral ear may depend on the residual hearing level, duration of hearing aid use, and others. In this study, we collected patients with bimodal amplification and aimed to evaluate the factors related to the hearing performance. Materials and Methods: This retrospective study included forty-nine patients who used cochlear implantation in one ear and a hearing aid in the contralateral ear for more than one year. Hearing level, an inner ear anomaly, and benefit of amplification were collected. A subjective benefit of amplification was measured by the Korean version of the Speech, Spatial and Qualities of Hearing Scale (KSSQ). K-SSQ score was calculated by the summation of each point of 12 questions (-5 ~ +5), and +24 points were used to be a cut off value of positive gain. Results: The average age of cochlear implantation is 6.7 years old. Thirty-six out of 49 (73.5%) showed a positive gain in K-SSQ when the hearing aids were used in the presence of cochlear implantation. Monosyllabic word recognition was better in the bimodal stimulation (8.4% increase). K-SSQ score showed a significant correlation with the low-frequency hearing level with contralateral cochlear implantation only and with the hearing level at 250 and 500Hz with bimodal amplification. There was also a significant correlation between the speech discrimination score and the K-SSQ score after the bimodal amplification. K-SSQ score showed no significant correlation with age at implantation, duration of use of cochlear implantation, and duration of use of hearing aid. Conclusions: A subjective benefit of amplification has a correlation with the low-frequency residual hearing level in the ear with hearing aid. [ABSTRACT FROM AUTHOR]

Background and Objectives: Intellectual ability is a crucial factor in the outcome of a cochlear implant, and Social maturity score (SMS) is an indirect predictor of intellectual capacity. The purpose of this study was to investigate the effect of SMS on cochlear implant and clinical significance in children with syndromes or disabilities. Methods: This study included children who underwent cochlear implant before seven years and diagnosed with various syndromes or disabilities during the preoperative examination. We analyzed the score of SMS and result of a cochlear implant by retrospective chart review. Results: We analyzed data from a total of 36 pediatric patients with cochlear implants diagnosed various syndromes or disabilities. Mean operation age was 2.5±1.4 years, and mean follow up period was 53.5±39.6 months. Mean SMS score was 70.4±29.2, and 20 patients (55.6%) showed a deterioration of SMS. Sixteen patients (44.4%) were normal, 11 (30.1%) were mild (50-69), 4 (11.1%) were moderate (35-49), 4 (11.1%) were severe (20-34), and 1 (2.8%) was profound (<20). Mean MAIS (Meaningful Auditory Integration Scale) and CAP (Categories of Auditory performance) of mild to moderate SMS deterioration group (Group 2) were 69.6±27.4 and 3.9±1.7, that was not significantly inferior to that of normal SMS group (Group 1). Mean MAIS and CAP of the severe to profound SMS deterioration group (Group 3) were 74.6±23.5 and 3.4±1.4. Although CAP of Group 3 was significantly lower than that of Group 1 (5.2±2.1, p=0.05), MAIS of Group 3 was not inferior to that of Group 1 or Group 2, and MAIS and CAP of Group 3 showed gradual improvement after the cochlear implant. Conclusion: Children with syndromes or disabilities frequently showed SMS deterioration. MAIS and CAP were not worse in SMS deteriorated patients, and gradual auditory improvement also detected even in the severe to profound SMS deterioration group. [ABSTRACT FROM AUTHOR]

Objectives: We investigated the effects of preoperative factors on outcomes of CIs in postlingually deaf adults using a general linear model (GLM) and a nonlinear Regression Forest Regression (RFR) model. Study Design: Postoperative monosyllabic word recognition scores (WRS) served as the dependent variable to predict. Predictors included duration of deafness, duration of auditory deprivation (duration of deafness without hearing aid use), age at implantation, preoperative hearing threshold and monosyllabic WRS in quiet. Patients: Postlingually deaf adults (n = 120) who received CI, which was fully inserted, without any inner ear abnormalities or combined disabilities and with follow-up of more than 2 years. Methods: The prediction accuracy was evaluated with the mean absolute error (MAE) as well as the Pearson's correlation coefficient between the true WRS and predicted WRS. To determine the importance of predictors, we measured increase in the MAE when a given variable was omitted in the regression model relative to when it was included. We used a leave-one-out cross-validation to avoid bias related to inclusion of the test data into the training procedure. Results: The fitting of GLMs resulted in prediction performance with correlation coefficient r=0.7 and MAE of 15.6+/-9.5). On the other hand, the RFR machine learning yielded superior prediction performance to the GLM with r=0.96 and MAE of 6.1+/-4.7 (t=9.8; p<0.00001). Computation of the importance showed that the contribution of DAD to the prediction was the highest (MAE increase when omitted: 12.1), followed by duration of deafness (8.6) and AgeCI (8.3). In a subsequent analysis, a subgroup of patients with DAD ≤ 10 years showed higher postCI WRS and smaller variation than those with DAD > 10 years. Conclusion: The current study on clinical utility of machine learning on auditory outcomes of CIs in postlingually deaf adults demonstrated that an advanced nonlinear classifier yields a highly accurate prediction ability with an error of +/-6 in WRS. Our finding also suggests that CI should be implemented no later than a sensitive period (10 years) after deafness to lead to successful outcome. Finally, our machine learning technique has the potential for patient counseling and predicting benefit from CI to patients. [ABSTRACT FROM AUTHOR]