The relativity of integrity testing by telemetry in the diagnosis of cochlear implant defect: A case study and literature review

Objective

This paper report a rare case that showed the limitation of integrity testing by telemetry in detecting the cause of cochlear implant defect.

Method

We are reporting the case of a 45-year-old female who received a cochlear implant 10 years ago, owing to a profound bilateral sensorineural hearing loss. Following the cochlear implant the patient's speech discrimination threshold improved dramatically.In March 2009, after a car accident, the patient was unable to hear. The clinical and radiological examination revealed no abnormality, nor did the telemetry test, with normal implant function and normal NRT. The proceeding medical treatment with a corticosteroid therapy and hearing rehabilitation brought no improvement. Thus we decided to revise both implantations.

Result

The cochlear reimplantation was postoperatively found to have brought a marked improvement in the hearing and speech discrimination threshold. Conclusively we chose to perform a second cochlear reimplantation on the opposite side which after surgery revealed the same postoperative result.

Conclusion

The telemetry test does not always enable one to discover the cause of the cochlear implant failure.     

Cochlear implantation after renal transplantation

Objective

Cochlear implantation after renal transplantation is uncommon and poses unique challenges that have only recently been described in the medical literature. This work reports our experience with cochlear implantation in patients who have undergone renal transplantation.

Study Design

A retrospective review was performed.

Setting

This study was performed in a tertiary academic medical center.

Patients

Two patients were identified as having undergone cochlear implantation after renal transplantation.

Interventions

Uneventful unilateral cochlear implantations were performed.

Main Outcome Measures

Postoperative complications to include wound infection or dehiscence were reported as well as audiometric data.

Results

Cochlear implantation was completed uneventfully in both patients without postoperative complications. One patient expired two years after the procedure as a result of multiple comorbidities. Both patients achieved successful use of their device.

Conclusions

This study adds to the growing evidence that successful cochlear implantation can be achieved in appropriately selected renal transplant patients. Decision making should rely on surgical candidacy as well as assessment of surgical risk in collaboration with the transplant service.     

Behavioral and electrophysiological measures of auditory change detection in children following late cochlear implantation: A preliminary study

Objective

The purpose of the current study was to longitudinally assess the development of automatic sound feature discrimination and compare it to behavioral discrimination in late-implanted cochlear implant users.

Methods

Scalp-recorded auditory evoked potentials (AEPs) and behavioral discrimination of frequency, duration and intensity differences within an oddball paradigm using complex stimuli were recorded in three late-implanted cochlear implant subjects beginning on turn-on day.

Results

Variable results were obtained in behavioral and AEPs that were consistent with the amount of pre-implant auditory experience each subject had. The best user showed rapid development of neurophysiologic indices of change detection along with improvement in behavioral and real-world auditory skills. In contrast, there were no recordable AEPs in the poorer CI user and there was little change in behavioral outcomes.

Conclusion

There is evidence of utilization of usual auditory processing pathways in the AEPs of some children who receive cochlear implants late in their childhood. Some plasticity in the auditory cortical pathways may be present despite prolonged auditory deprivation in school-aged children who are late-implanted cochlear implant recipients.     

The relationship between EAP and EABR thresholds and levels used to program the nucleus 24 speech processor: data from adults

OBJECTIVE: The objective of this study was to determine the relationship between electrically evoked whole nerve action potential (EAP) and electrical auditory brain stem response (EABR) thresholds and MAP threshold (T-level) and maximum comfort level (C-level) for subjects who use the Nucleus 24 cochlear implant system. DESIGN: Forty-four adult Nucleus 24 cochlear implant users participated in this study. EAP thresholds were recorded using the Neural Response Telemetry System developed by Cochlear Corporation. EABR thresholds were measured for a subset of 14 subjects using standard evoked potential techniques. These physiologic thresholds were collected on a set of five electrodes spaced across the cochlea, and were then compared with behavioral measures of T-level and C-level used to program the speech processor. RESULTS: EAP thresholds were correlated with MAP T- and C-levels; however, the correlation was not strong. A technique for improving the correlation by combining measures of T- and C-levels made on one electrode with the EAP thresholds was presented. Correlations between predicted and measured T- and C-levels using this technique were 0.83 and 0.77, respectively. Similar results were obtained using the EABR thresholds for a smaller set of subjects. In general, EABR thresholds were recorded at levels that were approximately 4.7 programming units lower than EAP thresholds. CONCLUSIONS: Either EAP or EABR thresholds can be used in combination with a limited amount of behavioral information to predict MAP T- and C-levels with reasonable accuracy.     

Simultaneous translabyrinthine removal of acoustic neuroma and cochlear implantation

Objectives

To report of a 65-year-old woman with bilateral Meniere's disease was referred for cochlear implantation (CI) due to severe/profound sensorineural hearing loss.

Methods

During the assessment workup, a vestibular schwannoma in the right ear was found by MR imaging. She underwent a translabyrinthine removal of the acoustic neuroma (AN) with sparing of the cochlear nerve and concurrent ipsilateral CI with a Nucleus Freedom device (Cochlear Ltd., Lane Cove, New South Wales, Australia).

Results

Complete removal of the AN was achieved without complications. Neural Response Telemetry (NRT) measurements, which showed poor morphology at the intraoperative tests, rapidly improved after activation, similarly to electrically evoked auditory brainstem responses (E-ABR). The patient reached 100% speech perception performances within 2 months from implantation, in the monaural condition. She was relieved from vertigo spell up to 14 months after the operation.

Conclusion

Cochlear implantation at the time of acoustic neuroma removal with VIII nerve sparing can be a safe and effective hearing restoration procedure.     

Efficacy of using NRT thresholds in cochlear implants fitting,in prelingual pediatric patients

ObjectiveTo evaluate the efficacy of using neural response telemetry (NRT) thresholds in predicting behavioural thresholds during programming of cochlear implant in prelingual children.MethodProspective study of 28 cochlear implants implanted with Nucleus 24 cochlear implant. We recorded NRT-thresholds on electrode numbers 1, 6, 11, 16 and 22 of the electrode array in each patient, the neural response thresholds were correlated with the behavioural map after six months of programming the device.ResultsThe mean neural response telemetry level was significantly higher than the mean threshold level (T-level) but lower than the comfortable level (C-level) in all the electrodes tested. NRT levels could statistically significantly predict T behavioural levels and comfortable behavioural levels, p < 0.01. There was a strong positive correlation between comfortable thresholds and neural response telemetry level measurements and behavioural threshold level and neural response telemetry threshold measurements.ConclusionThere is a useful role for neural response telemetry values in predicting the behavioural threshold and comfortable values in prelingual children. Combining the NRT values with behavioural observations can improve the programming of cochlear implants.     

Dynamic changes in microRNA expression during differentiation of rat cochlear progenitor cells in vitro

Objective

Cochlear progenitor cells could be used to explore the cochlea developmental mechanism and for cell replacement therapy in deafness. MicroRNAs are small, noncoding RNAs that could regulate the cell fate of stem cells, as well as cellular proliferation, differentiation and maturation. An expression profile analysis of microRNAs is necessary to understand their complex roles in differentiating cochlear progenitor cells.

Methods

The microRNAs microarray was used to analyze microRNA expression changes while differentiating cochlear progenitor cells. Quantitative real-time polymerase chain reaction was used to confirm and compare the results of the microarray and to detect the expression pattern of several microRNAs during the differentiation of neural stem cells.

Results

Nearly 100 microRNAs were identified from the microarray. Most showed changes in expression levels as cochlear progenitor cell differentiation progressed. The quantitative real-time polymerase chain reaction result demonstrated that the miR-183 family exhibits cell-specific expression in cochlear progenitor cells compared with neural stem cells.

Conclusions

The temporal regulation of these microRNAs indicated that they might play different roles in differentiating cochlear progenitor cells, and that specific microRNAs might influence the cell fate determination of cochlear progenitor cells.     

神经反应遥测技术在人工耳蜗术后调试中的应用

目的通过对小儿人工耳蜗植入者术后言语处理器调试中运用NRT（神经反应遥侧）技术效果的分析．探讨NRT在人工耳蜗术后调试中的应用价值。方法选取10例术后主观调试配合欠佳的儿童．用Cochlear公司NRT3．0编程软件进行ECAP波形检测并测定ECAP阈值，利用测试结果判断主观阈值（T-值）和最大舒适阈（C-值），并得出言语处理器映射图（Map）。术后6个月行声场听阈测听。结果86．2％的电极引出ECAP波形，开机调试时反应阈值较小，以后逐渐升高，3～4个月左右闽值逐渐趋于稳定，而且靠近蜗底的阈值比蜗尖高。声场平均听阈为30～40dBSPL。经过言语康复训练，获得良好的效果。结论NRT技术可为术后快速准确地调试言语处理器提供客观依据．     

Articulation skills in Turkish speaking children with cochlear implant

Objective

The benefits of using cochlear implant (CI) on speech perception and production have been documented. The aim of this study is to investigate the effect of age of cochlear implantation performed and length of auditory experience with CI on the development of articulation skills in prelingual children with CI.

Methods

For this purpose, 14 children with CI were administered through the standardized articulation test named AAT (Ankara Articulation Test). In order to evaluate the development of articulation skills, AAT was applied to each child with CI at the first and the fourth years of CI. The test group was selected among those congenitally hearing impaired children who had used hearing aids bilaterally before the age of one and a half, and received intervention after fitting hearing aids. The test group was divided into two subgroups: Group 1 consisted of the children implanted at and below the age of 3 and Group 2 consisted of the children implanted after the age of 3. Evaluations of articulation skills between groups and within groups were performed in the first and fourth years of implantation. In the study, nonparametric statistics have been used to compare the test scores. Mann-Whitney U-test and Wilcoxon test have been used in the comparisons made between groups and within groups, respectively.

Results

While there has not been observed any statistically significant difference between the first year articulation skills of children with CI at and below the age of three and children with CI above the age of 3, for the fourth year this difference has been found to be statistically significant.

Conclusions

The results demonstrate the importance of the early application of CI and length of auditory experience with CI in the development of articulation skills.     

Measuring communicative performance with the German version of the FAPCI-instrument: normative data and longitudinal results

Objective

The German version of the Functioning after Paediatric Cochlear Implantation (FAPCI) inventory was designed to capture the communicative performance of cochlear implanted children. In order to be able to compare cochlear-implanted children to their normal hearing peers, normative growth curves were designed. Furthermore it was of interest how the communicative performance develops over time and whether it is influenced by age at implantation.

Method

A polynomial regression curve was fit to the data of 133 normal hearing children. This normative curve was compared to individual growth curves of 90 cochlear implanted children. The cochlear-implanted study sample was split up into four groups depending on the age at implantation.

Results

The normative growth curve increases from 1 year of age until saturation is reached with 3 years of age. The individual FAPCI trajectories of cochlear implanted children are heterogeneous, but in general they are delayed in comparison to the normative growth curve. “Early implanted children” follow the development of their normal hearing peers more closely than “later-implanted children”.

Conclusion

The German version of the FAPCI parental questionnaire constitutes an additional instrument in monitoring the communicative performance development of cochlear implanted children and allows for comparison to normal hearing peers.     

Effect of stylet removal on neural response telemetry and stapedial reflex thresholds during cochlear implantation

Objective

The purpose of this study was to analyze changes in neural response telemetry (NRT) and electrically evoked stapedial reflex thresholds (ESRT) before and after stylet withdrawal during cochlear implant surgery.

Methods

Thirty children (21–92 months old) who were candidates for cochlear implantation took part in this study. In all of them Nucleus Contour Advance was implanted. NRT and ESRT responses were recorded initially with the stylet in and then when the stylet was taken out during the implant procedure. The recordings were performed in the basal, middle, and apical areas of the electrode array.

Results

The threshold levels required to obtain NRT and ESRT responses after stylet removal were lower. This decrease was observed in all parts of the cochlea. It was statistically significant in all areas with the exception of the basal ESRT measurements.

Conclusion

Withdrawing the stylet results in better NRT and ESRT responses, most probably due to a favorable position change of the electrode array within the scala tympani.     

The development of auditory skills in infants with isolated Large Vestibular Aqueduct Syndrome after cochlear implantation

Objective

The purpose of this study was to investigate the auditory performance of infants with isolated Large Vestibular Aqueduct Syndrome (LVAS) after cochlear implantation, compare their performance with those of infants with a normal inner ear, and establish a database of auditory development.

Method

435 infants with congenital severe to profound hearing loss participated in this study. 62 infants in group A were diagnosed with isolated LVAS. 373 infants in group B had a normal inner ear. Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS) was used to evaluate the development of auditory skills.

Results

The mean scores for auditory ability showed no significant difference between groups A and B. The mean scores for the three different auditory skills increased significantly over time. The differences were statistically significant in mean scores among the three different auditory skills for group B.

Conclusion

Auditory skills of infants with isolated LVAS developed rapidly after cochlear implantation, in a similar manner to those of infants with a normal inner ear. Cochlear implantation is an effective interventional approach and an established therapeutic option for infants with isolated LVAS.     

Adding the third dimension—A new tool for constructing 3D models of the airway from 2D bronchoscopic video

Objective

To develop a new method of using existing bronchoscopic video technology to generate a 3D model of the airway for clinical purposes.

Design

Prospective pilot study with clinical correlation.

Methods

A Storz 7200 bronchoscope was used to obtain video of a standardized tube. The images were then processed using “open source” tools which detected feature points. A three dimensional model was then constructed using these feature points. An in-house 3D image program was then used to compare the 3D model with the standardized tube. Video from a representative airway patient who had previously had a CT of the chest and a bronchoscopic examination was also analyzed using this technique. The 3D model was correlated with CT images to clinically validate this technique.

Setting

Tertiary care hospital.

Patients

One airway patient video was used for clinical validation.

Outcome measures

(1) Average diameters of the 3D video derived tube model were compared to the actual tube and (2) a cross section of the 3D video derived patient model was compared to the patient CT derived model.

Results

Repeated measures on standardized tubes demonstrated that is it possible to construct an airway model using this novel technique with a less than 5% error. Further, it is possible to construct a 3D model from patient video using existing brochoscopic technology.

Conclusions

It is possible to extract 3D data from a sequence of 2D images. Further, this 3D model can be used for the purposes of management and planning and is quantitatively accurate and reliable. Initial data suggests that these measurements correlate with actual airway size and may provide a better instrument with which to make surgical decisions.     

Evolution of communication abilities after cochlear implantation in prelingually deaf children

Objective

This study tries to evaluate different factors on communication ability outcomes in cochlear implanted children.

Methods

Communication abilities are studied using the validated APCEI-scale based on five components of the language: cochlear implant acceptance, perceptive language performance, comprehension of the oral orders, expressive language and speech intelligibility.APCEI-scores were calculated every 6 months for the first 2 years, then yearly.The studied variables were: gender, social origin, preoperative residual hearing, age, aetiology of hearing loss, and associated disabilities.

Results

Communication ability scores increased with high socioeconomic level, presence of residual hearing, younger patients when no residual hearing, connexin mutation related deafness, and absence of associated disabilities. No significant difference has been noted between both sexes.

Conclusion

Many different factors influence the evolution of communication abilities of cochlear implanted children.Investigating the cause of hearing loss, presence of associated disabilities and residual hearing before surgery may help to predict outcome and plan appropriate care to those children with negative predictive factors.     

Measuring communicative performance with the FAPCI instrument: preliminary results from normal hearing and cochlear implanted children

Objective

: To develop preliminary “growth curves” of Functioning after Pediatric Cochlear Implantation (FAPCI) scores using a cross-sectional sample of normal hearing children and to compare these curves to trajectories of FAPCI scores in children receiving cochlear implants.

Methods

: Quantile regression was used to develop growth curves from the FAPCI scores of a cross-sectional sample of 82 normal hearing children (age range 7 months-5 years). Trajectories of FAPCI scores from a longitudinal cohort of 75 children with cochlear implants (age range 1-5 years) were compared to these growth curves.

Results

: FAPCI scores were positively associated with increasing age in normal hearing children with a rapid increase in scores observed at earlier ages followed by a plateau at age 3 years. FAPCI trajectories for cochlear-implanted children varied with age at implantation and did not reach a plateau until age 5-6 years.

Conclusion

: Normal hearing children demonstrated increasing FAPCI scores with age, and these preliminary growth curves allow for the interpretation of a cochlear-implanted child's FAPCI scores in comparison to normal hearing children. Additional research using a larger, longitudinal cohort of normal hearing children will be needed to develop definitive normative FAPCI trajectories.     

Characteristics of hearing impairment in Yemeni children with chronic suppurative otitis media: A case-control study

Background

Chronic suppurative otitis media (CSOM) is a serious disorder particularly in low resource settings. It can lead to disabling hearing impairment and sometimes life-threatening infective complications.

Objective

The aim of the present study was to describe the characteristics of hearing impairment associated with CSOM in Yemeni children.

Methods

A case-control study of 75 children with CSOM and 74 healthy controls. Hearing was assessed by behavioural testing and audiometry.

Results

Cases had lower academic performance than controls (OR 15.31, 95% CI 1.99-322.14, p < 0.001). Disabling hearing impairment >30 dB was present in 51.5% (right ear) and 66.7% (left ear) of children with CSOM.

Conclusion

Disabling hearing impairment was identified as a major health problem in these Yemeni children with CSOM. There is a need for investment to reduce the burden of CSOM and its complications in these communities. Greater attention to the chronic disabling effects of CSOM in children is required in poor communities and low resource settings.     

A comparison of in vitro treatments for directing stem cells toward a sensory neural fate

Purpose

Low numbers of primary auditory neurons (ANs) may compromise the clinical performance of a cochlear implant. The focus of this research is to determine whether stem cells can be used to replace the ANs lost following deafness. To successfully replace these neurons, stem cells must be capable of directed differentiation into a sensory neural lineage in vitro and, subsequently, of survival and integration into the deafened cochlea.

Materials and Methods

In this study, we compared three in vitro treatments for directing the differentiation of mouse embryonic stem cells toward a sensory neural fate using neurotrophins, conditioned media from early post-natal cochlear epithelium, or media containing BMP4.

Results

In all treatments, stem cells were first exposed to retinoic acid, which was sufficient to induce Brn3a-positive patterning in 8-day differentiated embryoid bodies. After a further 8 days of differentiation in adherent culture conditions, BMP4 media-treated cultures produced higher proportions of cells expressing sensory neural markers in comparison to both the conditioned media and neurotrophin treatments, including significantly greater numbers of cells expressing peripherin (P ≤ .001), tyrosine receptor kinase B (P ≤ .001), and β-III tubulin (P ≤ .001).

Conclusions

This study illustrated that combined treatment with retinoic acid and BMP4 was most effective at directing differentiation of mouse stem cells into sensory-like neurons in vitro. This finding further supports the role of bone morphogenetic proteins in the differentiation of sensory neurons from neural progenitors, and provides a basis for allotransplantation studies for auditory neuron replacement in the deaf mouse cochlea.     

Transnasal endoscopic management of recurrent juvenile nasopharyngeal angiofibroma

Objectives

The purpose of this study was to present our experience with definitive endoscopic surgical management of the recurrent juvenile nasopharyngeal angiofibroma.

Study design

Retrospective study.

Setting

Tertiary care centre.

Materials and methods

This study includes 13 male adolescence patients with recurrent nasopharyngeal angiofibroma who received treatment at our centre between 2005 and 2010. The patient age ranged from 12 to 21 years (mean age, 15.7 years). Endoscopic two surgeons’ technique had been used. Follow up MRI every four months.

Results

Complete removal of the recurrent tumor was achieved in 10 cases. Three patients had incomplete removal with further recurrences. These recurrences were two in lateral wall of the sphenoid sinus (2 patients), and soft palate (one patient).

Conclusion

Recurrent JNAs are residual disease resulting from incomplete removal of the primary tumor. Transnasal endoscopic sinus surgery is an effective method for treating recurrent JNA. Follow up is essential and integral point in management of JNAs.     

A comparison of the proliferative capacity and ultrastructure of proliferative cells from the cochleae of newborn rats of different ages

Objective

Recent reports have shown that multipotent stem cells/progenitor cells that are capable of proliferation and regeneration are present in mammalian cochleae. However, progenitor cells have not been isolated from the adult cochlea. We examined the proliferative potential of cells derived from neonatal rats of various ages. The determination of the differences between the proliferative cells from rats of different ages may provide clues to the mechanisms controlling the destiny of these cells.

Methods

Proliferative cells were isolated from the cochleae of 1-, 7-, and 14-day-old rats, and the proliferative capacity and ultrastructure of the cells from each age group were assessed using flow cytometry and transmission electron microscopy, respectively.

Results

During the first two postnatal weeks, the number of proliferative cells gradually fell to zero. This decrease occurred in parallel with the impairment of the proliferative capacity of the cells and the accumulation of proliferative cells in G0/G1. In addition, some of the cells exited the cell cycle by means of gradual maturity and apoptosis.

Conclusions

Our study suggests that cochlear proliferative cells are remnants of the progenitor cells that originally gave rise to the sensory epithelium. The disappearance of the cochlear proliferative cells in adult mammalian cochleae may result from their differentiation and/or apoptosis.     

Cochlear implantation under the first year of age—The outcomes. A critical systematic review and meta-analysis

Objective

To review the current knowledge on cochlear implantation in infancy, regarding auditory perception/speech production outcomes.

Study-design

Meta-analysis. EBM level: II.

Methods

Literature-review from Medline and database sources. Related books were also included.

Results

The number of cohort-studies comparing implanted infants with under 2-year-old children was five; three represented type-III and two type-II evidence. No study was supported by type I evidence. Overall, 125 implanted infants were identified. Precise follow-up period was reported in 82. Median follow-up duration ranged between 6 and 12 months; only 17 children had follow-up duration equal or longer than 2 years. Reliable outcome measures were reported for 42 infants; 15 had been assessed with open/closed-set testing, 14 with developmental rating scales, and 13 with prelexical speech discrimination tools.Ten implanted infants assessed with open/closed-set measures had been compared with under 2-year-old implanted children; 4 had shown better performance, despite the accelerated rate of improvement after the first postoperative year.

Conclusion

Neuroplasticity/neurolinguistic issues have led cochlear implant centers to implant deaf children in infancy; however, widespread policies regarding the aforementioned issue are still not justified. Evidence of these children's outperformance regarding auditory perception/speech production outcomes is limited. Wide-range comparisons between infant implantees and under 2-year-old implanted children are lacking. Longer-term follow-up outcomes should be also made available. There is a need to develop and validate robust measures of monitoring implanted infants. Potential factors of suboptimal outcomes (e.g. misdiagnosis, additional disorders, device tuning, parental expectations) should also be weighted, when considering cochlear implantation in infancy.