A Study of Outcome of Pediatric Cochlear Implantation in Patients with Cochleovestibular Nerve Deficiency

Cochlear implantation programming characteristics and outcomes of cochlear nerve deficiency

PURPOSE

Due to the specificity of cochlear implantation (CI) programming parameters and outcomes in cochlear nerve deficiency (CND) patients, this study aimed to investigate the correlation between programming parameters and outcomes and further compare the difference between normal and CND groups.

METHODS

Ninety (95 ears) CND patients (normal cochlea, 39; malformed cochlea, 56) and seventy-nine (81 ears) normal cochlea patients who underwent CI surgery with either Med-El or Cochlear devices were included. The programming parameters and outcomes evaluated by the questionnaires were collected and compared among the normal CND, malformed CND, and normal groups in the two device groups, and their correlation was analyzed.

RESULTS

In the CND group, a reduced stimulation rate, higher pulse width, and triphasic pulse were needed in some cases. The stimulus levels of the CND group were significantly higher than that of the normal group (p < 0.05), but the outcomes of the CND group were significantly worse than that of the normal group (p < 0.05), and the stimulus level was significantly correlated with the outcomes (p < 0.05). However, there was no difference between normal and malformed CND groups. The non-auditory response was observed in the CND group, especially the ones with malformations.

CONCLUSION

The CI programming parameters of some CND patients need to be adjusted, and a slower stimulation rate and higher pulse width are required sometimes. CND patients need a higher stimulus level than normal patients but their outcomes are poorer. Non-auditory response should be noticed in CND patients during programming.

Audiological characteristics and cochlear implant outcome in children with cochlear nerve deficiency

Objectives

This study aimed to examine the audiological characteristics and validity of predicting outcomes of cochlear implants (CIs) in children with cochlear nerve deficiency (CND) based on the internal auditory meatus (IAM) nerve grading system.

Methods

The audiological characteristics of 188 ears in 105 children diagnosed with CND were analyzed based on the IAM nerve grading system. In addition, 42 children with CND who underwent CI were also divided into four groups based on the system, and their auditory and speech performance at baseline (preoperative) and 6, 12, and 24 months after CI were analyzed and compared with those of the control group (n = 24) with a normal cochlear nerve (CN) and CI.

Results

The audiological test results showed no significant differences among the four CND groups in terms of elicited rates of distortion product otoacoustic emission (DPOAE) (p = 1.000), auditory brainstem response (ABR) (p = 0.611), and cochlear microphonic (CM) (p = 0.167). Hearing in the CND IV group was significantly better than that in the CND I group (p < 0.05). In children with CI, the auditory and speech performance of the control group was significantly higher than all CND groups from 6 to 24 months (p < 0.05) and 12 to 24 months (p < 0.05), respectively. Meanwhile, there were no significant differences between each pair group in the four CND groups (p > 0.05).

Conclusion

Children with CND, including those in whom the CN was not visualized by MRI, can benefit from CI. Additionally, the IAM nerve grading system could not predict the outcomes of CI in children with CND.

Functional Outcomes of Cochlear Implantation in Children with Bilateral Cochlear Nerve Aplasia

Background and Objectives: Many otologists face a dilemma in the decision-making process of surgical management of patients with cochlear nerve (CN) aplasia. The goal of this study is to provide fresh evidence on cochlear implantation (CI) results in patients with CN aplasia. Materials and Methods: We scrutinized functional outcomes in 37 ears of 21 children with bilateral CN aplasia who underwent unilateral or bilateral CI based on cross-sectional and longitudinal assessments. Results: The Categories of Auditory Performance (CAP) scores gradually improved throughout the 3-year follow-up; however, variable outcomes existed between individuals. Specifically, 90% of recipients with a 1-year postoperative CAP score ≤1 could not achieve a CAP score over 1 even at 3-year postoperative evaluation, while the recipients with a 1-year postoperative CAP score >1 had improved auditory performance, and 72.7% of them were able to achieve a CAP score of 4 or higher. Meanwhile, intraoperative electrically evoked compound action potential was not correlated with postoperative CAP score. Conclusions: Our results further refine previous studies on the clinical feasibility of CI as the first treatment modality to elicit favorable auditory performance in children with CN aplasia. However, special attention should be paid to pediatric patients with an early postoperative CAP score ≤1 for identification of unsuccessful cochlear implants and switching to auditory brainstem implants.

Auditory perception in pediatric cochlear implant users with cochlear nerve hypoplasia

OBJECTIVES

The objectives of this study were to assess auditory perception and speech intelligibility outcomes in children with cochlear nerve (CN) hypoplasia who received cochlear implants (CIs) using Categories of Auditory Performance II (CAP II) and Speech Intelligibility Rating (SIR) scales.

METHODS

In total, 40 children who received CI and who were aged between 3 and 18 years were included in this study. The study group included 20 children with CN hypoplasia at least one ear, while the control group included 20 children with normal cochleas and cochlear nerve structures. All children in the study and control groups who participated were evaluated using the CAP II and the SIR scale. Demographic data were collected.

RESULTS

Significant differences were found between the study and control groups' CAP II and SIR scores (p < 0.001). It was found that CAP II scores were positively correlated with SIR scores in the study (r = 0.743, p < 0.001) and control (r = 0.601, p < 0.001) groups. In the study group, significant negative correlations were found between SIR scores and age at implantation (r = -0.674, p = 0.004) and between CAP II scores and age at implantation (r = 0.751, p = 0.003). In the control group, a significant negative correlation was found between age at implantation and CAP II scores (r = -0.805, p = 0.001). Similarly, a significant negative correlation was found between age at implantation and SIR scores (r = -0.702, p = 0.007).

CONCLUSION

Even for children with severe inner ear malformation and CN hypoplasia, CI is an effective treatment modality for auditory perception and speech production. However, it should be noted that CN hypoplasia affects auditory performance negatively in children with CI.

Value of Preoperative Imaging Results in Predicting Cochlear Nerve Function in Children Diagnosed With Cochlear Nerve Aplasia Based on Imaging Results

This study aimed to assess the function of the cochlear nerve using electrically evoked compound action potentials (ECAPs) for children with cochlear implants who were diagnosed with cochlear nerve aplasia and to analyze the correlation between preimplantation imaging results and ECAP responses. Thirty-five children diagnosed with cochlear nerve aplasia based on magnetic resonance imaging (MRI) were included. Preimplantation MRI and high-resolution computed tomography (HRCT) images were reconstructed, and the width of the bone cochlear nerve canal (BCNC), the diameter of the vestibulocochlear nerve (VCN), and the diameter of the facial nerve (FN) were measured. ECAP input/output (I/O) functions were measured at three electrode locations along the electrode array for each participant. The relationship between ECAP responses (including ECAP threshold, ECAP maximum amplitude, and slope of ECAP I/O function) and sizes of the BCNC and VCN was analyzed using Pearson's correlation coefficients. Our analysis revealed that ECAP responses varied greatly among individual participants. Overall, ECAP thresholds gradually increased, while maximum amplitudes and ECAP I/O function slopes gradually decreased, as the electrode location moved from the basal to the apical direction in the cochlea. ECAP responses exhibited no significant correlations with BCNC width or VCN diameter. The ratio of the VCN to FN diameters was significantly correlated with the slope of the ECAP I/O function and the maximum amplitude. BCNC width could not predict the function of the cochlear nerve. Compared with the absolute size of the VCN, the size of the VCN relative to the FN may represent an indicator for predicting the functional status of the cochlear nerve in children diagnosed with cochlear nerve aplasia based on imaging results.