Expanding pediatric cochlear implant candidacy: A case study of electro-natural stimulation (ENS) in partial deafness treatment

Searching for the Molecular Basis of Partial Deafness

Hearing is an important human sense for communicating and connecting with others. Partial deafness (PD) is a common hearing problem, in which there is a down-sloping audiogram. In this study, we apply a practical system for classifying PD patients, used for treatment purposes, to distinguish two groups of patients: one with almost normal hearing thresholds at low frequencies (PDT-EC, n = 20), and a second group with poorer thresholds at those same low frequencies (PDT-EAS, n = 20). After performing comprehensive genetic testing with a panel of 237 genes, we found that genetic factors can explain a significant proportion of both PDT-EC and PDT-EAS hearing losses, accounting, respectively, for approx. one-fifth and one-half of all the cases in our cohort. Most of the causative variants were located in dominant and recessive genes previously linked to PD, but more than half of the variants were novel. Among the contributors to PDT-EC we identified OSBPL2 and SYNE4, two relatively new hereditary hearing loss genes with a low publication profile. Our study revealed that, for all PD patients, a postlingual hearing loss more severe in the low-frequency range is associated with a higher detection rate of causative variants. Isolating a genetic cause of PD is important in terms of prognosis, therapeutic effectiveness, and risk of recurrence.

The Clinical Effect of Steroid Therapy on Preserving Residual Hearing after Cochlear Implantation with the Advanced Bionics HiRes Ultra 3D Cochlear Implant System

(1) Background: The main aim of this study was to assess the clinical effectiveness of two different schemes of administration of steroids ((1) dexamethasone administered intravenously in comparison with (2) combination of steroid treatments: orally administered prednisone and intravenously administered dexamethasone) in comparison with a control group (no steroid administration) on hearing preservation (HP) in patients who underwent an Advanced Bionics cochlear implantation. (2) Methods: Thirty-five adult patients met the inclusion criteria. All patients were randomly divided into three subgroups depending on the scheme of steroid administration: (1) the first subgroup with only intravenously administered dexamethasone (0.1 mg per kg body weight twice a day for three days), (2) the second subgroup with a combination of methods of administration of steroids (intravenous and oral steroid therapy (dexamethasone, 0.1 mg/kg body weight twice a day plus prednisone, 1 mg/kg weight once a day for three days before surgery and after administration of dexamethasone (4th, 5th, 6th day) and after this time the dose of prednisone was reduced)) and (3) the third subgroup without steroid therapy (control group). The results were measured by pure tone audiometry (PTA) in three periods: (1) before implantation, (2) during activation of the processor (one month after implantation), and (3) 12 months after activation. Patients’ hearing thresholds before implantation were on average 82 dB HL, 77 dB HL, and 88 dB HL, respectively. (3) Results: The majority of the patients from the first subgroup had hearing preserved partially (77.8%). A similar result was observed in the second study group (oral + i.v.) (partial hearing preservation was found in 61.5% of the participants). The opposite was true in the control group; a plurality of control patients (38.5%) had no measurable hearing 12 months after the activation of the processor. (4) Conclusions: Pharmacological treatment consisting of the administration of steroids in patients who had undergone cochlear implantation with the Advanced Bionics HiRes Ultra 3D cochlear implant system may be beneficial for preserving residual hearing in patients.

False Belief Understanding in Deaf Children With Cochlear Implants

Theory of mind (ToM) is crucial for social interactions. Previous research has indicated that deaf and hard-of-hearing children born into hearing families (DoH) are at risk of delayed ToM development. However, it is unclear whether this is the case for DoH children who receive cochlear implants (CIs) before and around the second year of life. The present study aimed to investigate false belief understanding (FBU) in DoH children with CIs. The relationships between false belief task (FBT) performance, sentence comprehension, age at implantation, duration of CI use, and Speech Recognition Threshold were explored. A total of 94 children with typical levels of hearing (TH) and 45 DoH children (age range: 3-8), who received their first CI between 6 and 27 months of age, were tested on the FBT and a sentence comprehension test. Results showed that 4- and 5-year-old children with CIs performed significantly worse than their peers with TH on the FBT; 6- to 8-year-old children with CIs performed similarly to age-matched children with TH. Age at implantation and duration of CI use were correlated with sentence comprehension but not with the FBT. The results indicated that FBU was delayed until the age of 6 years in most of children with CIs.

Vestibular Function After Cochlear Implantation in Partial Deafness Treatment

Introduction: Cochlear implantation is a fully accepted method of treating individuals with profound hearing loss. Since the indications for cochlear implantation have broadened and include patients with low-frequency residual hearing, single-sided deafness, or an already implanted ear (meaning bilateral cochlear implantation), the emphasis now needs to be on vestibular protection.

Materials and Methods: The research group was made up of 107 patients operated on in the otorhinolaryngosurgery department: 59 females and 48 males, aged 10.4–80.2 years (M = 44.4; SD = 18.4) with hearing loss lasting from 1.4 to 56 years (M = 22.7; SD = 13.5). The patients underwent cVEMP, oVEMP, a caloric test, and vHIT assessment preoperatively, and, postoperatively, cVEMP and oVEMP at 1–3 months and a caloric test and vHIT at 4–6 months.

Results: After cochlear implantation, there was postoperative loss of cVEMP in 19.2% of the patients, oVEMP in 17.4%, reduction of caloric response in 11.6%, and postoperative destruction of the lateral, anterior, and posterior semicircular canal as measured with vHIT in 7.1, 3.9, and 4% respectively.

Conclusions: Hearing preservation techniques in cochlear implantation are connected with vestibular protection, but the risk of vestibular damage in never totally eliminated. The vestibular preservation is associated with hearing preservation and the relation is statistically significant. Informed consent for cochlear implantation must include information about possible vestibular damage. Since the risk of vestibular damage is appreciable, preoperative otoneurological diagnostics need to be conducted in the following situations: qualification for a second implant, after otosurgery (especially if the opposite ear is to be implanted), having a history of vestibular complaints, and when there are no strict audiological or anatomical indications on which side to operate.

Cochlear Implantation and Electric Acoustic Stimulation in Children With TMPRSS3 Genetic Mutation

BACKGROUND

Mutations in the TMPRSS3 gene, although rare, can cause high frequency hearing loss with residual hearing at low frequencies. Several previous studies have reported cochlear implant (CI) outcomes for adults with TMPRSS3 mutation with mixed results. Although some studies have suggested that TMPRSS3 is expressed in spiral ganglion cells, it remains unclear if previously reported poor CI outcomes in this population were secondary to long durations of deafness or to the effects of the TMPRSS3 mutation. To date, no studies in the literature have reported CI outcomes for children with TMPRSS3 mutation treated with CI.

OBJECTIVE

The current case series aimed to describe outcomes for three children with sloping hearing loss caused by TMPRSS3 mutation who underwent bilateral CI.

STUDY DESIGN

Case series.

SETTING

Academic medical center.

PATIENTS

Three children (3-4 yr) with TMPRSS3 mutation and normal sloping to profound high frequency hearing loss.

INTERVENTIONS

CI and electric acoustic stimulation (EAS).

MAIN OUTCOME MEASURES

Outcome measures were residual hearing thresholds, speech recognition scores, and electrode placement determined via intraoperative CT imaging.

RESULTS

All three children maintained residual acoustic hearing and received benefit from EAS. Mean change in low-frequency pure-tone average was 17 dB. Mean postoperative word and sentence recognition scores in the bilateral EAS condition were 80 and 75%, respectively.

CONCLUSIONS

Results indicate that CI with EAS is an appropriate treatment for children with TMPRSS3 genetic mutation. Pediatric results from this case series show more favorable CI outcomes than are currently reported for adults with TMPRSS3 mutation suggesting that the intervention may be time sensitive.

Evolving Criteria for Adult and Pediatric Cochlear Implantation

The indications for cochlear implantation have gradually expanded as advancements in technology have evolved, resulting in improved audiologic outcomes for both adult and children. There remains a significant underutilization of cochlear implant technology in the United States, and recognition of the potential benefits of cochlear implantation for non-traditional indications is critical for encouraging the evolution of candidacy criteria. Adult cochlear implantation candidacy has progressed from patients with bilateral profound sensorineural hearing loss (SNHL) to include patients with greater degrees of residual hearing, single-sided deafness and asymmetric hearing, and atypical etiologies of hearing loss (eg, vestibular schwannoma, Ménière's disease, and otosclerosis). Indications for pediatric cochlear implantation have similarly evolved from children with bilateral severe to profound SNHL to implanting children at a younger age, including those with residual hearing, asymmetric hearing loss, inner ear malformations, as well as cochlear nerve deficiency. In this editorial, the literature investigating cochlear implantation for nontraditional indications is reviewed with an aim to use the best available evidence to encourage the evolution of candidacy criteria.

Vestibular status in partial deafness

Introduction

The hair cells of the cochlea and the vestibulum are closely connected and may be susceptible to the same noxious factors. The relationship between their function has been a continuing field of investigation. The indications for cochlear implantation have been broadened and now include the patients with partial deafness. This raises the question of their vestibular status.

Objective

The aim of the study was to investigate whether there is any difference between the vestibular function of patients with low frequency residual hearing and those with totally deaf ears.

Methods

A total of 360 ears with profound sensorineural hearing loss were analysed before cochlear implantation. The patients were divided into four groups, according to their low frequency residual hearing (Group 1 ‒ normal or slightly elevated low frequency residual hearing; Group 2 ‒ elevated threshold but still usable hearing at low frequencies; Group 3 – non-functional residual hearing; Group 4 ‒ no detectable hearing threshold within the limits of the audiometer). The patients underwent vestibular tests: cervical vestibular evoked myogenic potential, ocular vestibular evoked myogenic potential, caloric test and video-head impulse test.

Results

The rates of elicited responses in cervical vestibular evoked myogenic potential were as follows: in Group 1 (59.3 %); Group 2 (57.5 %); Group 3 (35.2 %); Group 4 (7.7 %). For ocular vestibular evoked myogenic potential the percentage of correct outcomes was: Group 1 (70.8 %); Group 2 (56.0 %); Group 3 (40.0 %); Group 4 (14.3 %). For the caloric test we counted normal responses in 88.9 % of Group 1; 81.6 % of Group 2; 57.9 % of Group 3; 53.3 % of Group 4. For video-head impulse test we also found markedly better results in Group1, followed by Group 2, and much worse in Group 3 and 4.

Conclusion

Patients with partial deafness not only have a better cochlea but also better vestibular function, which needs to be protected. In summary, the better the low frequency residual hearing, the better the vestibular status.

Early general development and central auditory system maturation in children with cochlear implants - A case series

OBJECTIVES

A cochlear implant (CI) has the potential to improve the functioning of a deaf child in many aspects. Nevertheless, the dynamics of the general development, beyond the typically measured language abilities, directly after CI, is still unknown, especially if a child is implanted early. In this study we present a methodological framework for assessment of different domains of development, as well as the central auditory nervous system (CANS) maturation in infants and toddlers with a CI.

METHODS

Three children with bilateral congenital hearing loss and a unilateral CI, aged below 2.5 years, participated in a longitudinal study. Children were tested at three time points after cochlear implantation using the Polish Children Development Scale (CDS) consisting of a comprehensive battery of tests, as well as recordings of Cortical Auditory Evoked Potentials (CAEP).

RESULTS

All three children revealed gradual improvement in the overall CDS result as well as most of the CDS subscales. After 9 months of CI experience two younger children showed age-appropriate performance. In CAEP measurements a decrease of latency of the P1 component (an established biomarker of cortical auditory maturation) was observed in the same two children, with one achieving normal ranges of P1 latency after 9 months of CI use.

CONCLUSIONS

Our novel methodological framework can be successfully applied in small children with cochlear implants. It contributes to better understanding of the general development in early implanted children. The preliminary results indicate variability in children's performance in various developmental domains and thus the need to monitor the development of each child individually and holistically.

Effect on vestibular function of cochlear implantation by partial deafness treatment-electro acoustic stimulation (PDT-EAS)

Purpose

Although the cochlear implantation procedure does not interfere with vestibular structures directly, both the vestibulum and the cochlea share the same inner ear fluid space, and this fluid may be responsible for transferring possibly damaging forces from one to the other. The purpose of the study is to assess postoperative vestibular function after partial deafness treatment–electro-acoustic stimulation (PDT–EAS) cochlear implantation.

Methods

Fifty-five patients were included in the study (30 females, 25 males, age 11–80, mean 41.8 ± 19.35). cVEMP and oVEMP were performed preoperatively and 1–3 months after cochlear implantation. Caloric and vHIT tests were conducted preoperatively and 4–6 months after cochlear implantation.

Results

Our study shows that, based on a wide range of electrodes, use of PDT–EAS is protective in terms of preserving vestibular function. It gives a rate of saccular damage of 15.79%, utricular damage of 19.04%, and a horizontal semicircular canal response reduction of 15.79%.

Conclusions

PDT–EAS is protective in terms of preserving vestibular function. Nevertheless, it should be emphasized that the risk of vestibular damage cannot be totally eliminated even when hearing preservation techniques are adopted.

Expanding unilateral cochlear implantation criteria for adults with bilateral acquired severe sensorineural hearing loss

Objectives

To report on a retrospective cohort study on the effects of expanding inclusion criteria for application of cochlear implants (CIs) on the performance 1-year post-implantation.

Methods

Based on pre-implantation audiometric thresholds and aided speech recognition scores, the data of 164 CI recipients were divided into a group of patients that fulfilled conservative criteria (mean hearing loss at 0.5, 1 and 2 kHz > 85 dB HL and phoneme scores with hearing aids < 30%), and the remaining group of patients that felt outside this conservative criterion. Speech recognition scores (in quiet) and quality of life (using the NCIQ) of both groups, measured at 1-year post-implantation, were compared.

Results

The group that felt outside the conservative criterion showed a higher phoneme score at 1-year post-implantation compared to the conservative group, suggesting that relaxed criteria have a positive influence on the speech recognition results with CI. With respect to quality of life, both groups significantly improved 1-year post-implantation. The conservative group showed a higher benefit on the advanced perception domain of the NCIQ. Based on their worse pre-implantation hearing, this was expected.

Conclusions

The data suggest that relaxation of CI indication positively affects the speech recognition performance of patients with severe hearing loss. Both groups of patients showed a positive effect of CI on the quality of life. This benefit relates to communication skills and the subjective day-to-day functioning in society.

Radiologic measurement of cochlea and hearing preservation rate using slim straight electrode (CI422) and round window approach

Hearing preservation surgery constitutes a considerable branch of cochlear implantation surgery and is being steadily developed and perfected. The aim of the study was to verify if insertion of a cochlear implant electrode according to individually calculated linear insertion depth improves hearing preservation. We evaluated the relations between the size of a cochlea, insertion depth angle, linear insertion depth and hearing preservation rate (HP) according to Hearing Preservation Classification in a retrospective case review of 54 patients implanted with a slim straight electrode Nucleus CI422 in 2008-2011. Group HP was 0.75 at activation, 0.67 at 12 months (for 53 patients) and 0.60 at 24 months. In 53 cases, the mean insertion depth angle was 375° (SD 17°); mean calculated cochlear duct length 35.87 mm (SD 1.95); mean calculated linear insertion depth 23.14 mm (SD 1.68). There was no significantly relevant relation between HP values and angular insertion depth or insertion depth. Preoperative measurements of cochlea and specific parameters such as linear insertion depth have no effect on hearing preservation. Poor hearing preservation in some deep insertion cases cannot be explained entirely by the electrode position.

Preservation of Hearing Following Cochlear Implantation Using Different Steroid Therapy Regimens: A Prospective Clinical Study

Background

A prospective clinical study was conducted to assess different regimens of steroid therapy and preservation of hearing following cochlear implantation.

Material/Methods

Study participants were ≥18 years-of-age, with a cochlear duct length ≥27.1 mm measured by computed tomography (CT), with hearing sound levels in the range of 10–120 decibels (dB) and sound frequencies of 125–250 hertz (Hz); sound levels of 35–120 dB and frequencies of 500–1,000 Hz; sound levels of 75–120 dB and frequencies of 2,000–8,000 Hz. Study exclusion criteria included diseases with contraindications for steroid therapy or medications that increased the effects of steroids. Patients had cochlear implantation and were divided into three treatment groups: intravenous (IV) steroid therapy (standard steroid therapy): combined oral and IV steroid therapy (prolonged steroid therapy); and a control group (cochlear implantation without steroid therapy). Hearing preservation was established by pure tone audiometry based on the pre-operative and postoperative average hearing thresholds according to the formula developed by the HEARRING Network.

Results

There were 36 patients included in the study. In all cases, the cochlear implant electrode was inserted via the round window approach with a straight electrode length of 28 mm. Patients with combined oral and IV steroid therapy (prolonged steroid therapy) had better results when compared with patients with intravenous (IV) steroid therapy (standard steroid therapy) and the control group.

Conclusions

Prolonged steroid therapy using combined oral and IV steroids stabilized hearing thresholds and preserved hearing in adult patients following cochlear implantation.

Application of next‑generation sequencing to identify mitochondrial mutations: Study on m.7511T>C in patients with hearing loss

Interruptions in the activity of mitochondria induced by mutations in the mitochondrial genome (mtDNA) can be the source of numerous diseases including hearing loss (HL). One of the mitochondrial variants responsible for HL is the m.7511T>C mutation located in the mitochondrially encoded tRNA serine 1 (UCN) gene. Next-generation sequencing was used to search for the HL mutations in the whole mtDNA of 2 patients with maternal inheritance and real time-polymerase chain reaction was applied for population screening of the m.7511T>C mutation in a group of 1,644 patients with HL. Sequencing of the whole mtDNA in 2 probands revealed a homoplasmic m.7511T>C mutation. Inheritance of the m.7511T>C mutation has been confirmed in examined matrilineal relatives in both families. The mean age of HL onset was 14.1 years old with the mean degree of HL equaling 74.8 dB. A large-scale search for the m.7511T>C mutation among the patients with HL established the frequency of the m.7511T>C mutation at 0.12% among Polish patients with HL. In conclusion, this first report on central European patients harboring the m.7511T>C mutation reveals that the m.7511T>C may be important when diagnosing patients with maternally inherited HL.

Validation of the LittlEARS Auditory Questionnaire in cochlear implanted infants and toddlers

OBJECTIVES

The LittlEARS Auditory Questionnaire (LEAQ) has so far been validated to assess auditory development in groups of normal-hearing children in over 20 different languages. Considering the huge variability in auditory development of CI children, especially since candidacy criteria have been relaxed, additional evidence to validate the use of LEAQ scores in this particular population is needed. The aim of this study is to provide evidence for the reliability and validity of LEAQ scores for assessing the auditory development of CI infants and toddlers based on an evaluation of LEAQ's internal structure and its relation to other variables.

METHODS

The study was prospective, with sequential enrolment and within-subject repeated measures. It included 122 children with profound bilateral sensorineural hearing loss implanted at 6-22 months of age. All children were evaluated with the Polish version of LEAQ on the first day of CI activation and at each of four follow-up visits related to sound processor fitting. The study was undertaken in the light of current psychometric thinking about how assessment instruments should be validated. The main aim of the study was to obtain evidence for the validity of interpreting LEAQ measures from CI children in terms of auditory development. First, in order to collect evidence for score reliability and validity based on LEAQ's internal structure, the psychometric properties of LEAQ scores from CI children were determined. A second step was to confirm validity by investigating the effect of concomitant variables on LEAQ scores. Correlations between LEAQ score and duration of hearing aid (HA) use, and between LEAQ score and duration of CI use, were investigated. Additionally, group differences in LEAQ scores between: 1) early and late implanted children; 2) children with long and short HA experience prior to implantation; and 3) children who showed responses over a wide frequency range from using their HAs (prior to implantation) vs those who did not.

RESULTS

On each of the five administrations of LEAQ, the item difficulty indices increased (meaning the items became easier) and over the series they progressively increased with a range of: 0.01-0.62, 0.03-0.92, 0.09-1.00, 0.26-1.00, and 0.52-1.00. At the same time, item-total correlations were in the ranges: 0.09-0.77, 0.26-0.62, 0.00-0.65, 0.00-0.65, and 0.00-0.67. Cronbach's alpha values were above 0.80 for all administrations. A positive correlation between LEAQ score and duration of HA use, and subsequent duration of CI use (hearing experience) was found. When the children were stratified into groups according to age at cochlear implantation, duration of HA use before implantation, and audibility provided by HAs prior to implantation, the differences between the groups were reflected in both their rate of auditory development and their LEAQ score.

CONCLUSION

The interpretation of LEAQ scores from CI children in terms of auditory development was supported by the validity evidence of internal structure and from a logical relationship to other variables. (1) Psychometric properties - item difficulty, item-total correlations, and Cronbach's alpha values - indicate that LEAQ measures are highly consistent and reliably gauge the level of a CI child's auditory development. (2) There was a positive correlation between LEAQ scores and the duration of hearing experience with HAs and a later CI; similarly, there were significant differences between groups of children stratified according to the age at cochlear implantation, duration of HA use before implantation, and audibility provided by HAs prior to implantation, all of which demonstrate the expected relation between LEAQ score and concomitant variables.