Vestibular function in children with auditory neuropathy spectrum disorder

Objective

Children with auditory neuropathy spectrum disorder (ANSD) account for about 10% of paediatric patients referred for cochlear implantation. Vestibulopathy may be associated with ANSD, and may have implications when formulating management plans in this patient group. We wanted to determine the incidence and predictive factors for vestibulopathy in this patient group to guide vestibular testing in this patient population, and give insight to the aetiology of ANSD.

Methods

We reviewed the outcomes of vestibular function testing in a cohort of paediatric patients with ANSD.

Results

Probable or definite vestibulopathy was seen in 42% of patients who were tested. Vestibulopathy was associated with medical co-morbidities, but was not associated with imaging findings.

Conclusions

Vestibulopathy is relatively prevalent in this patient group, and should be considered when planning the investigation and management of children with ANSD.     

The limitations of computed tomography in adult cochlear implant evaluation

Objective

To demonstrate the added value of magnetic resonance imaging (MRI) over computed tomography (CT) during adult cochlear implant evaluation.

Patients

Two adult patients are discussed in whom MRI studies diagnosed bilateral vestibular schwannomas during cochlear implant candidacy evaluation.

Interventions

Temporal bone CT and MRI.

Main outcome measure

Diagnosis of NF2.

Results

Two adult patients, ages 67 and 68 years, were evaluated for cochlear implant candidacy. Both patients experienced slowly progressive, bilateral hearing loss without complaints of vertigo, and neither patient had a family history of hearing loss or neurogenic tumors. Both patients had near-symmetric pure tone thresholds on audiometric testing. An MRI and a CT scan were performed on both patients, and bilateral vestibular schwannomas were identified on MRI.

Conclusions

Though MRI is not routinely utilized in adult cochlear implant evaluation, it may be of greater clinical value than CT in the setting of adult-onset hearing loss. MRI allows for sensitive evaluation of cochlear patency and architecture, and cochlear nerve status. As demonstrated in the two index cases, MRI also provides the added benefit of evaluating for causes of retrocochlear hearing loss. These two patients would have likely experienced a significant delay in diagnosis of NF2 without preoperative MRI, particularly given the limitations of scanning following CI magnet placement.     

人工耳蜗植入术后患者前庭诱发肌源性电位的研究

目的探讨人工耳蜗植入术对患者前庭功能的影响。方法本研究入选对象为2001年至2009年由同一术者行人工耳蜗植入手术,且均为术后6个月以上年龄大于6岁的患者。排除1例非前庭因素自行放弃使用人工耳蜗者,共有12例患者参与本研究。应用前庭诱发肌源性电位（vestibular evoked myogenic potential,VEMP）检查进行前庭功能检测,以p13、n23波潜伏期与振幅作为评定指标。结果12例患者双侧短声刺激p13波和n23波出现率为50%（6/12）。诱发出波形的手术耳组p13潜伏期与非手术耳组相比,两者无显著性差异（P＞0.05）。手术耳组n23潜伏期与非手术耳组相比,两者无显著性差异（P＞0.05）。|p13-n23|手术耳组与非手术耳组相比,两者无显著性差异（t=0.009,P＞0.05）。手术耳组振幅低于非手术耳组振幅,差异具有统计学意义（t=3.75,P<0.05）。结论人工耳蜗植入术对VEMP的传导并无影响,但可造成手术耳VEMP振幅下降,可能与人工耳蜗植入术的手术刺激或长期的电极植入对球囊功能的影响有关。     

Cochlear implantation in children with cochlear nerve deficiency

Objective

The aim of this study was to report on auditory performance after cochlear implantation in children with cochlear nerve deficiency.

Methods

A retrospective case review was performed. Five patients with pre-lingual profound sensorineural hearing loss implanted in an ear with cochlear nerve deficiency participated in the study. Postoperative auditory and speech performance was assessed using warble tone average threshold with cochlear implant, speech perception categories, and speech intelligibility ratings. All patients underwent high resolution computed tomography and magnetic resonance imaging.

Results

According to Govaerts classification, three children had a type IIb and two a type IIa cochlear nerve deficiency. Preoperatively, four patients were placed into speech perception category 1 and one into category 2. All patients had an improvement in hearing threshold with the cochlear implant. Despite this, at the last follow-up (range 18–81 months, average 45 months), only one girl benefited from cochlear implantation; she moved from speech perception category 2 to 6 and developed spoken language. Another child developed closed set speech perception and had connected speech that was unintelligible. The other 3 children showed little benefit from the cochlear implant and obtained only an improved access to environmental sounds and improved lipreading skills. None of these 4 children developed a spoken language, but they were all full-time users of their implants.

Conclusions

The outcomes of cochlear implantation in these five children with cochlear nerve deficiency are extremely variable, ranging from sporadic cases in which open set speech perception and acquisition of a spoken language are achieved, to most cases in which only an improved access to environmental sound develops. Regardless of these limited outcomes, all patients in our series use their device on a daily basis and derive benefits in everyday life. In our opinion, cochlear implantation can be a viable option in children with cochlear nerve deficiency, but careful counseling to the family on possible restricted benefit is needed.     

Vestibular-evoked myogenic potentials in cochlear implant children

CONCLUSIONS: Our results suggest that the sacculi of most children with cochlear implants can easily be damaged, as shown by the absence of vestibular-evoked myogenic potentials (VEMPs) in response to click stimuli. Also, in most of the children, the vestibular nerve was seemingly not stimulated by the cochlear implant. These results suggest that electrical stimulation at the C level can stimulate the cochlear nerve; however, this stimulation did not spread to the vestibular nerve in our children. In some children with Mondini dysplasia or vestibulocochlear nerve abnormality, the vestibular nerve was stimulated when the cochlear implant device was on, because of a VEMP response to electrical stimulation. OBJECTIVE: To clarify the diagnostic value of VEMPs in cochlear implant patients. MATERIAL AND METHODS: The click-evoked myogenic potentials of 12 children who underwent cochlear implantation surgery were investigated. The latency and amplitude of the VEMP responses were measured. RESULTS: Before surgery, 6 of the 12 children showed normal VEMPs, 1 showed a decrease in the amplitude of VEMPs and five showed no VEMP response. After surgery, with the cochlear implant device off, 1 child showed a decreased VEMP and 11 showed no VEMPs. With the cochlear implant device on, four children showed VEMPs and eight did not.     

Acquisition of early auditory milestones with a cochlear implant

Objective

Speech acquisition after cochlear implant is a long process. Various studies have followed the auditory milestones in the early period after implantation. The aim of the present study was to track the development of hearing skills in the early period after cochlear implantation and evaluate which factors influence the process.

Methods

195 records of children implanted in the Hadassah Medical Center were examined retrospectively. Data on etiology, age at implantation and type of implant were collected. In addition, information on the rate of progress was measured: the first time that there was detection and identification of Ling sounds, the first time it was possible to obtain SDT (speech detection threshold), SRT (speech reception threshold) and an audiogram, and the first accurate repetition of VCV (vowel consonant vowel) sounds.

Results

Results show a consistent pattern of auditory milestone acquisition similar to that of normal development, from milestones that do not require decoding beginning with SDT, detection of Ling sounds followed by an audiogram which requires cooperation, to tasks that involve decoding starting with SRT and repetition of Ling sounds and finally VCV repetition.The children implanted before 24 months of age achieved the auditory milestones later than children implanted between 2 and 6 years, apparently since these tasks involve cognitive abilities which are not yet developed in the youngest children.Previous hearing experience improved the rate of acquisition of the auditory milestones and progress was faster in the second implanted ear compared to the first implanted ear.

Conclusion

More research is needed to address the relationship between acquisition of early auditory milestones and performance with the cochlear implant later on in life.     

Development of Mandarin spoken language after pediatric cochlear implantation

Objective

The purpose of this study was to evaluate early spoken language development in young Mandarin-speaking children during the first 24 months after cochlear implantation, as measured by receptive and expressive vocabulary growth rates. Growth rates were compared with those of normally hearing children and with growth rates for English-speaking children with cochlear implants.

Method

Receptive and expressive vocabularies were measured with the simplified short form (SSF) version of the Mandarin Communicative Development Inventory (MCDI) in a sample of 112 pediatric implant recipients at baseline, 3, 6, 12, and 24 months after implantation. Implant ages ranged from 1 to 5 years. Scores were expressed in terms of normal equivalent ages, allowing normalized vocabulary growth rates to be determined. Scores for English-speaking children were re-expressed in these terms, allowing direct comparisons of Mandarin and English early spoken language development.

Results

Vocabulary growth rates during the first 12 months after implantation were similar to those for normally hearing children less than 16 months of age. Comparisons with growth rates for normally hearing children 16–30 months of age showed that the youngest implant age group (1–2 years) had an average growth rate of 0.68 that of normally hearing children; while the middle implant age group (2–3 years) had an average growth rate of 0.65; and the oldest implant age group (>3 years) had an average growth rate of 0.56, significantly less than the other two rates. Growth rates for English-speaking children with cochlear implants were 0.68 in the youngest group, 0.54 in the middle group, and 0.57 in the oldest group. Growth rates in the middle implant age groups for the two languages differed significantly.

Conclusions

The SSF version of the MCDI is suitable for assessment of Mandarin language development during the first 24 months after cochlear implantation. Effects of implant age and duration of implantation can be compared directly across languages using normalized vocabulary growth rates. These comparisons for Mandarin and English reveal comparable results, despite the diversity of these languages, underscoring the universal role of plasticity in the developing auditory system.     

The effect of pre-operative developmental delays on the speech perception of children with cochlear implants

Objective

The objective of this study was to evaluate the relationship between developmental delays and speech perception in pre-lingually deafened cochlear implant recipients.

Methods

This study was a retrospective review of patient charts conducted at a tertiary referral center. Thirty-five pre-lingually deafened children underwent multichannel cochlear implantation and habilitation at the Kyoto University Hospital Department of Otolaryngology-Head and Neck Surgery. A pre-operative cognitive–adaptive developmental quotient was evaluated using the Kyoto scale of psychological development. Post-operative speech performance was evaluated with speech perception tests two years after cochlear implantation. We computed partial correlation coefficients (controlled for age at the time of implantation and the average pre-operative aided hearing level) between the cognitive–adaptive developmental quotient and speech performance.

Results

A developmental delay in the cognitive–adaptive area was weakly correlated with speech perception (partial correlation coefficients for consonant–vowel syllables and phrases were 0.38 and 0.36, respectively).

Conclusion

A pre-operative developmental delay was only weakly associated with poor post-operative speech perception in pre-lingually deafened cochlear implant recipients.     

Working memory in Farsi-speaking children with normal development and cochlear implant

Aim and background

Working memory has an important role in language acquisition and development of cognition skills. The ability of encoding, storage and retrieval of phonological codes, as activities of working memory, acquired by audition sense. Children with cochlear implant experience a period that they are not able to perceive sounds. In order to assess the effect of hearing on working memory, we investigated working memory as a cognition skill in children with normal development and cochlear implant.

Methods

Fifty students with normal hearing and 50 students with cochlear implant aged 5–7 years participated in this study. Children educated in the preschool, the first and second grades. Children with normal development were matched based on age, gender, and grade of education with cochlear implant.Two components of working memory including phonological loop and central executive were compared between two groups. Phonological loop assessed by nonword repetition task and forward digit span. To assess central executive component backward digit span was used. The developmental trend was studied in children with normal development and cochlear implant as well. The effect of age at implantation in children with cochlear implants on components of working memory was investigated.

Results

There are significant differences between children with normal development and cochlear implant in all tasks that assess working memory (p < 0.001). The children's age at implantation was negatively correlated with all tasks (p < 0.001). In contrast, duration of usage of cochlear implant set was positively correlated with all tasks (p < 0.001). The comparison of working memory between different grades showed significant differences both in children with normal development and in children with cochlear implant (p < 0.05).

Conclusion

These results implied that children with cochlear implant may experience difficulties in working memory. Therefore, these children have problems in encoding, practicing, and repeating phonological units. The results also suggested working memory develops when the child grows up. In cochlear implant children, with decreasing age at implantation and increasing their experience in perceiving sound, working memory skills improved.     

Vestibular function outcomes after vestibular neurectomy in Meniere disease: Can vestibular neurectomy provide complete vestibular deafferentation?

Objective

Vestibular neurectomy is considered the reference treatment of incapacitating vertigo accompanying Meniere disease, with an efficiency rate of 85–95% in most literature reports.The aim of this study is to evaluate if vestibular neurectomy can provide a complete vestibular deafferentation by investigating complete vestibular function after surgery.

Methods

Prospective study. Twenty-four patients suffering from incapacitated Meniere vertigo crisis beneficiated from a vestibular neurectomy by retrosigmoid approach. The average time between surgery and vestibular evaluation was 1 year. We performed (i) kinetic test, (ii) caloric test and (iii) vibration-induced nystagmus (VIN) at 30, 60 and 100 Hz under videonystagmography recording, (iv) vestibular evoked myogenic potentials (VEMP), (v) video head impulsed test (VHIT) for each semicircular canals and (vi) an evaluation of visual vertical and horizontal subjective (VVS and HVS).

Results

On clinical evaluation, all the patients except one had never experienced any recurrence of vertigo crisis after surgery. The 24 patients would definitely undergo the surgery again. On vestibular evaluation, on the operated side, all patients showed a total areflexia at caloric test; 23 patients had no VEMP response; 23 patients had abolished canals response to VHIT. All the patients had VVS and HVS deviated towards the operated side; 23 patients had a high velocity VIN from 30 to 60 Hz.

Conclusion

This study proves that vestibular neurectomy can provide a complete vestibular deafferentation. We discuss this vestibular evaluation protocol and the main difficulties encounter during surgery, which could lead to partial nerve section and partial relief, and explain residual vestibular function after vestibular neurectomy.     

Oral communicating children using a cochlear implant: Good reading outcomes are linked to better language and phonological processing abilities

Introduction/objective

Cochlear implantation provides children with a significant hearing loss the potential to engage in phonological processing via audition; however these children can still have poor or inadequately detailed mental (phonological) representations of speech and as such phonological awareness and reading difficulties. Heterogeneous participant profiles, particularly varying modes of communication have clouded the research regarding reading outcomes of children using a cochlear implant. The objective of this study was to explore the relationships between word reading and reading comprehension outcomes, and a range of variables of a relatively homogenous group of children using cochlear implants.

Method

Forty-seven oral communicating children using a cochlear implant and who had attended auditory-verbal therapy served as participants. They were administered a comprehensive battery of 10 different assessments covering 22 different tasks across the domains of speech perception, speech production, language, phonological processing and reading. Correlation and principal component analyses were used to examine the relationships between outcome areas.

Results

Audiologic and demographic variables were not significantly related to reading outcomes, with the exception of family size. Language and word reading were most strongly related to reading comprehension, while phonological awareness and language were most strongly related to word reading. It is proposed that the development of well-specified phonological representations might underlie these relationships.

Conclusion

For oral communicating children using a cochlear implant, good reading outcomes are linked to better language and phonological processing abilities.     

Paediatric cochlear implantation in north-western Nigeria case report and review of our challenges

Objective

To report the commencement of cochlear implantation (CI) in children in Northern Nigeria and review the challenges encountered with a view to establishing CI programme.

Cases

Two children with post-meningitic sensorineural hearing loss had standard pre-implantation assessment and cochlear implantation surgery in Nigeria in conjunction with surgeons from another developing country. Post-implantation meningitis was encountered and managed in one of the patients. Post-CI rehabilitation started in a foreign country and continued in our centre after training of our speech therapist. Both patients had improvement in their hearing.

Conclusion

These showcase successful CI in patients from Sub-Saharan Africa, the challenges included need for development of surgical and post-CI rehabilitation personnel and affordability of the cost of the implant. The support of all the stakeholders needed for commencement of a CI programme was noted.     

Tinnitus after cochlear implantation

Objective

The purpose of this study was to investigate properties of tinnitus which starts after cochlear implantation. Of the 17 adult patients in our cochlear implant group, four (23.5%) who had no pre-implantation tinnitus were eligible for the study.

Methods

Each patient was requested to complete a short questionnaire regarding his or her experience with tinnitus. Tinnitus match test was performed for each patient by using an Interacoustic Clinical Audiometer (model AC40; Assens, Denmark).

Results

Tinnitus match test revealed a tinnitus frequency of a 4 KHz for three and of a 6 KHz for one patient. Mean value of the loudness score was calculated as 17.5 dB SL.

Conclusions

The results of this study emphasize the importance of counseling patients regarding risks of tinnitus after cochlear implantation.     

HRCT and MRI findings in X-linked non-syndromic deafness patients with a POU3F4 mutation

Objective

The aim of this study was to analyze HRCT and MRI findings in patients with X-linked non-syndromic deafness and a POU3f4 mutation.

Methods

HRCT and MRI data of four patients (males, 2–19 years old) with a POU3f4 mutation were collected and a retrospective review was performed. Cochlea, internal auditory canal (IAC), vestibule, semicircular canals, vestibular aqueduct, nerve canals in the IAC fundus, stapes and cochlear nerve were evaluated on 2D images (multi-planner reformation, MPR) and cochlear foramen on 3D images (CT virtual endoscopy, CTVE). Ten cases with normal hearing subjected to CT and MR exams served as controls.

Results

Inner ear malformations were bilateral and symmetrical. Cochlear malformation was shown to consist of as a relatively normal outer coat shape, absence of a cochlear modilous, and a direct intercommunication between the IAC and cochlear inner cavity. The lateral portion of the IAC was dilated. A spiral cochlear inner cavity was observed with CTVE images versus a helical cochlear nerve foramen as seen in controls. The labyrinthine facial nerve canal and superior vestibular nerve canal were enlarged. The Bill's bar was hypertrophic and partially pneumatized. A thickened stapes footplate was present and a fissura ante fenestram was absent in seven ears examined. A column shaped stapes was observed in one ear.

Conclusions

The absence of a cochlear modilous with a dilated lateral IAC and thickened stapes footplate were the remarkable features observed with imaging these in X-linked non-syndromic deafness patients with a POU3F4 mutation. Preoperative recognition of the image features in these patients is important because it precludes stapedectomy and indicates the risks in the surgery of cochlear implantation including CSF gusher and electrode insertion into IAC.     

Auditory performance and speech intelligibility of Mandarin-speaking children implanted before age 5

Objectives

(1) To report the auditory performance and speech intelligibility of 84 Mandarin-speaking prelingually deaf children after using cochlear implants (CIs) for one, two, three, four, and five years to understand how many years of implant use were needed for them to reach a plateau-level performance; (2) to investigate the relation between subjective rating scales and objective measurements (i.e., speech perception tests); (3) to understand the effect of age at implantation on auditory and speech development.

Methods

Eighty-four children with CIs participated in this study. Their auditory performance and speech intelligibility were rated using the Categorical Auditory Performance (CAP) and the Speech Intelligibility Rating (SIR) scales, respectively. The evaluations were made before implantation and six months, one, two, three, four, and five years after implantation. At the fifth year after implantation, monosyllabic-word, easy-sentence, and difficult-sentence perception tests were administered.

Results

The median CAP score reached a plateau at category 6 after three years of implant use. The median SIR arrived at the highest level after five years of use. With five years of CI experiences, 86% of the subjects understood conversation without lip-reading, and 58% were fully intelligible to all listeners. The three speech perception tests had a moderate-to-strong correlation with the CAP and SIR scores. The children implanted before the age of three years had significantly better CAP and monosyllabic word perception test scores.

Conclusions

Five years of follow-up are needed for assessing the post-implantation development of communication ability of prelingually deafened children. It is recommended that hearing-impaired children receive cochlear implantation at a younger age to acquire better auditory ability for developing language skills. Constant postoperative aural–verbal rehabilitation and speech and language therapy are most likely required for the patients to reach the highest level on the CAP and SIR scales.     

Inferences and metaphoric comprehension in unilaterally implanted children with adequate formal oral language performance

Objectives

To assess skills in inferences during conversations and in metaphors comprehension of unilaterally cochlear implanted children with adequate abilities at the formal language tests, comparing them with well-matched hearing peers; to verify the influence of age of implantation on overall skills.

Methods

The study was designed as a matched case–control study. 31 deaf children, unilateral cochlear implant users, with normal linguistic competence at formal language tests were compared with 31 normal hearing matched peers. Inferences and metaphor comprehension skills were assessed through the Implicit Meaning Comprehension, Situations and Metaphors subtests of the Italian Standardized Battery of “Pragmatic Language Skills MEDEA”. Differences between patient and control groups were tested by the Mann–Whitney U test. Correlations between age at implantation and time of implant use with each subtest were investigated by the Spearman rank correlation coefficient.

Results

No significant differences between the two groups were found in inferencing skills (p = 0.24 and p = 0.011 respectively for Situations and Implicit Meaning Comprehension). Regarding figurative language, unilaterally cochlear implanted children performed significantly below their normal hearing peers in Verbal Metaphor comprehension (p = 0.001). Performances were related to age at implantation, but not with time of implant use.

Conclusions

Unilaterally cochlear implanted children with normal language level showed responses similar to NH children in discourse inferences, but not in figurative language comprehension. Metaphors still remains a challenge for unilateral implant users and above all when they have not any reference, as demonstrated by the significant difference in verbal rather than figurative metaphors comprehension. Older age at implantation was related to worse performance for all items. These aspects, until now less investigated, had to receive more attention to deeply understand specific mechanisms involved and possible effects of different levels of figurative language complexity (presence or absence of contextual input, degree of transparency and syntactic frozenness). New insight is needed to orient programs in early intervention settings in considering and adequately responding to all these complex communicative need of children with hearing loss.     

Evaluation of cortical processing of language by use of positron emission tomography in hearing loss children with congenital cytomegalovirus infection

Objective

To predict cochlear implant efficacy and investigate the cortical processing of the visual component of language in profoundly deafened patients with asymptomatic congenital cytomegalovirus (CMV) infection.

Methods and cases

The cortical activity of two children with CMV-related hearing loss was evaluated with fluorodeoxyglucose-positron emission tomography (FDG-PET) with a visual language task before cochlear implantation. Total development and auditory perception ability were assessed one year after implantation.

Results

The two children with CMV-related hearing loss showed activation in the auditory association area where no activation was found in the controls, and exhibited nearly identical cortical activation patterns to those seen in patients with profound congenital hearing loss. In contrast, differences in total development in verbal ability and discrimination of sentences between the two cases were revealed one year after implantation.

Conclusion

These results might indicate that the differences of cortical activities according to hearing abilities could have been influenced by CMV infection that involves higher function of the brain directly and/or affects the cochlea peripherally. Additionally, if CMV infection might have affected only the cochlea, these cortical activation patterns were influenced secondary by the time course of hearing loss characterized by CMV infection, which had varied manifestations.Accurate diagnosis and cochlear implantation at the appropriate time are important for successful speech development, and each patient needs a personalized habilitation program based on their etiology and brain function.     

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

Objective

To 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.

Methods

A 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.

Results

There were two children of electrode array misplacement into the superior semicircular canal complication, and the rate was 0.28%.

Conclusions

Electrode 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.     

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.