Cochlear implants in infants and toddlers

Outcomes of Hearing Aid and Cochlear Implantation in Case of Congenital Non-Syndromic Bilateral Severe to Profound Sensorineural Hearing Loss: An Observational Study

This study was done to measure the outcomes of hearing aid (HA) and cochlear implantation (CI) in case of congenital non syndromic severe to profound sensorineural hearing loss (SNHL) by using aided audiometry (AA), categories of auditory perception (CAP) score and speech intelligibility rating (SIR) scale. The objectives were to find out the effective management options available for bilateral severe to profound SNHL, to study the impact of age of CI on language development and to study the outcome of HA and CI. Patients with congenital severe to profound SNHL were included in the study. Initially the case history of the participants was taken then they underwent audiological tests to confirm hearing loss. To assess the outcomes of HA and CI, they were initially fitted with high gain digital behind the ear HA, then underwent auditory verbal therapy for twelve months, after that AA, CAP and SIR test done to measure the outcomes of HA and similar hierarchy followed for CI. The results showed that with HA, the benefit is very limited whereas with CI the benefit is significant. The average SIR score of HA and CI are 1 and 3.16 and average CAP score are 0.83 and 7.8 respectively. The study shows that the CI is one of the most effective management options available for severe to profound SNHL and found that early intervention followed by early detection of hearing loss helps in achieving better speech and language skills.

Are Auditory Steady-State Responses Useful to Evaluate Severe-to-Profound Hearing Loss in Children?

Objective. To evaluate Auditory Steady-State Responses (ASSR) at high intensities in pediatric cochlear implant candidates and to compare the results to behavioral tests responses. Methods. This prospective study evaluated 42 children with suspected severe-to-profound hearing loss, aged from 3 to 72 months. All had absent ABR and OAE responses. ASSR were evoked using binaural single frequency stimuli at 110 dB HL with a 10 dB down-seeking procedure. ASSR and behavioral test results were compared. Results. Forty-two subjects completed both ASSR and behavioral evaluation. Eleven children (26.2%) had bilateral responses. Four (9.5%) showed unilateral responses in at least two frequencies, all confirmed by behavioral results. Overall 61 ASSR responses were obtained, most (37.7%) in 500 Hz. Mean thresholds were between 101.3 and 104.2 dB HL. Among 27 subjects with absent ASSR, fifteen had no behavioral responses. Seven subjects showed behavioral responses with absent ASSR responses. No spurious ASSR responses were observed at 100 or 110 dB HL. Conclusion. ASSR is a valuable tool to detect residual hearing. No false-positive ASSR results were observed among 42 children, but in seven cases with absent ASSR, the test underestimated residual hearing as compared to the behavioral responses.

Are auditory steady-state responses a good tool prior to pediatric cochlear implantation?

INTRODUCTION

ASSR allow frequency-specific evaluation in intensities up to 120dB HL and detection of residual hearing in patients with severe-to-profound hearing loss.

AIM

to compare ASSR thresholds and behavioral test results in children with suspected severe-to-profound hearing loss.

METHODS

Cross sectional study to compare ASSR and behavioral responses (VRA or audiometry) in 63 pediatric cochlear implant candidates (126 ears) aged between 6 and 72 months. We included children with normal otomicroscopy, absent responses to click-ABR and otoaccoustic emissions. We excluded children with inner ear malformations, auditory neuropathy spectrum disorder or who did not complete VRA or achieve EEG noise<30nV during the ASSR test. Air-conduction ASSR stimuli were continuous sinusoidal tones presented at 0.5, 1, 2 and 4kHz starting at 110dB HL. Behavioral thresholds were acquired with warble tones presented at 0.5, 1, 2 and 4kHz in each ear through insert or head phones at maximum presentation level of 120dB HL.

RESULTS

Behavioral thresholds were obtained in 36.7% (185/504) of all frequencies in all subjects, 9% in intensities >110dB HL. Among 504 ASSR measurements, 53 thresholds were obtained (10.5%). Overall 89.5% of the tested frequencies did not show any response at 110dB HL. Most responses were at 500Hz. Mean differences between behavioral and ASSR thresholds varied from 0.09 to 8.94dB. Twenty-seven comparisons of behavioral and ASSR thresholds were obtained: 12 at 0.5kHz, 9 at 1kHz, 5 at 2kHz and 1 at 4kHz. Absent responses were observed in both tests in 38.1% at 0.5kHz, 52.4% at 1kHz, 74.6% at 2kHz and 81.0% at 4kHz. Specificity was>90% at 1, 2 and 4kHz. In ears with no behavioral response at 120dB HL all ASSR thresholds were in the profound hearing loss range, 90% of them were ≥110dB HL.

CONCLUSION

Among 63 pediatric CI candidates, absent responses to high-intensity ASSR was the major finding (specificity>90%) predicting behavioral thresholds in the profound hearing loss range. These findings can be helpful to confirm the decision for cochlear implantation.

Diffusion tensor imaging and MR spectroscopy of microstructural alterations and metabolite concentration changes in the auditory neural pathway of pediatric congenital sensorineural hearing loss patients

PURPOSE

Our objective was to evaluate age-dependent changes in microstructure and metabolism in the auditory neural pathway, of children with profound sensorineural hearing loss (SNHL), and to differentiate between good and poor surgical outcome cochlear implantation (CI) patients by using diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRS).

MATERIALS AND METHODS

Ninety-two SNHL children (49 males, 43 females; mean age, 4.9 years) were studied by conventional MR imaging, DTI and MRS. Patients were divided into three groups: Group A consisted of children≤1 years old (n=20), Group B consisted of children 1-3 years old (n=31), and group C consisted of children 3-14 years old (n=41). Among the 31 patients (19 males and 12 females, 12m- 14y ) with CI, 18 patients (mean age 4.8±0.7 years) with a categories of auditory performance (CAP) score over five were classified into the good outcome group and 13 patients (mean age, 4.4±0.7 years) with a CAP score below five were classified into the poor outcome group. Two DTI parameters, fractional anisotropy (FA) and apparent diffusion coefficient (ADC), were measured in the superior temporal gyrus (STG) and auditory radiation. Regions of interest for metabolic change measurements were located inside the STG. DTI values were measured based on region-of-interest analysis and MRS values for correlation analysis with CAP scores.

RESULTS

Compared with healthy individuals, 92 SNHL patients displayed decreased FA values in the auditory radiation and STG (p<0.05). Only decreased FA values in the auditory radiation was observed in Group A. Decreased FA values in the auditory radiation and STG were both observed in B and C groups. However, in Group C, the N-acetyl aspartate/creatinine ratio in the STG was also significantly decreased (p<0.05). Correlation analyses at 12 months post-operation revealed strong correlations between the FA, in the auditory radiation, and CAP scores (r=0.793, p<0.01).

CONCLUSIONS

DTI and MRS can be used to evaluate microstructural alterations and metabolite concentration changes in the auditory neural pathway that are not detectable by conventional MR imaging. The observed changes in FA suggest that children with SNHL have a developmental delay in myelination in the auditory neural pathway, and it also display greater metabolite concentration changes in the auditory cortex in older children, suggest that early cochlear implantation might be more effective in restoring hearing in children with SNHL. This article is part of a Special Issue entitled SI: Brain and Memory.

Language achievement in children who received cochlear implants between 1 and 2 years of age: group trends and individual patterns

This study examined receptive and expressive vocabulary and grammar achievement of French-speaking children (n = 27) who received a cochlear implant (CI) between the age of 1 and 2. Standardized measures of language achievement were administered and the language levels attained by children with CIs were compared with that of the normative sample of same-age hearing peers for each measure. As a group, children exhibited language levels within normal limits in all standardized language measures. Examination of individual patterns revealed four different language profiles ranging from normal language levels in all domains to general language delay. Half the participants displayed language levels on par with similar-age peers at the word level; less than half the children obtained average performance at the sentence level. In three of these profiles, comprehension of sentences was impaired. Moreover, the age at implantation was not associated with language achievement. Findings suggest that receiving a CI between the age of 1 and 2 years does not ensure that language abilities will be within normal limits after up to 6 years of experience with the implant.

Communication development in children who receive the cochlear implant younger than 12 months: risks versus benefits

BACKGROUND

The advent of universal neonatal hearing screening in some countries and the availability of screening programs for at-risk infants in other countries has facilitated earlier referral, diagnosis, and intervention for infants with hearing loss. Improvements in device technology, two decades of pediatric clinical experience, a growing recognition of the efficacy of cochlear implants for young children, and the recent change in the U.S. Food and Drug Administration's age criteria to include children as young as 12 mo has led to increasing numbers of young children receiving cochlear implants. Evidence to support provision for infants younger than 12 mo is extrapolated from physiological studies, studies of children using hearing aids, and studies of children older than 12 mo of age with implants. To date, however, there are few published research findings regarding communication development in children between 6 and 12 mo of age who receive implants. The current study hypothesized that earlier implantation would lead to increased rates of language acquisition as the children were still in the critical period for their development.

METHOD

A retrospective review was completed for 19 infants (mean age at implantation, 0.88 yr; range, 0.61-1.07, SD 0.15) and 87 toddlers (mean age at implantation, 1.60 yr; range, 1.13-2.00, SD 0.24) who received the multichannel implant in Melbourne, Australia. Preimplantation audiological assessments for these children included aided and unaided audiograms, auditory brain stem response, auditory steady state response (ASSR), and otoacoustic emission and indicated profound to total bilateral hearing loss in all cases. Communication assessment included completion of the Rossetti Infant-Toddler Language Scale and educational psychologists' cognitive and motor assessment. Computed tomography scan, magnetic resonance imaging, and surgical records for all cases were reviewed. Postimplantation language assessments were reported in terms of the rate of growth over time on the language comprehension and language expression subscales of the Rossetti Infant-Toddler Language Scale.

RESULTS

Results demonstrated that cochlear implantation may be performed safely in very young children with excellent language outcomes. The mean rates of receptive (1.12) and expressive (1.01) language growth for children receiving implants before the age of 12 mo were significantly greater than the rates achieved by children receiving implants between 12 and 24 mo, and matched growth rates achieved by normally hearing peers. These preliminary results support the provision of cochlear implants for children younger than 12 mo of age within experienced pediatric implantation centers.

Cochlear implantation in children with internal ear malformations

OBJECTIVE

To evaluate surgical aspects and results of cochlear implantation in inner ear malformations.

STUDY DESIGN

Retrospective cohort study.

SETTING

Ear, nose, and throat department of a tertiary referral hospital.

PATIENTS

Out of 260 implanted children, 18 (6.9%) had inner ear malformations: complex cochleovestibular malformation (n = 11), common cavity (n = 1), and enlarged vestibular aqueduct (EVA) (n = 6). Deafness was progressive in 12 cases (G1) and congenital in 6 cases (G2). Genetics lead to diagnosis in 12 of 13 cases: PSD mutation (n = 11), Waardenburg syndrome (n = 1), negative (1). Mean age at implant was 7.8 years. Mean follow-up period was 48 months.

MAIN OUTCOME MEASURES

Medical and surgical outcomes were reported. Closed (CSW) and open (OSW) set word perception and level of speech production were evaluated each year. The results were compared pre- and postoperatively and between the two groups.

RESULTS

Gusher at surgery was observed in 50% of cases, with a persistent leak in one case. No facial injury or infectious complications were observed. At 12 months, 83% of the population had achieved more than 75% recognition in CSW, versus 16% before implant (p = 0.001). After 2 years, 64% of patients had more than 50% recognition in OSW. Good oral language was seen in 76% at 2 years and 100% at 3 years, versus 55% before implant (respectively, p > 0.05 and p = 0.03). At 1 year after implant, 83% of the G1 and 20% of the G2 achieved more than 50% recognition in OSW (p = 0.02). After 24 months, 83% of G1 and 40% of G2 had more than 50% in OSW (p > 0.05). Before implant, 75% in G1 and 0% in G2 had good oral language (p = 0.01). At 1 year, 83% in G1 and 16% in G2 had good oral language (p = 0.02). At 2 years, 100% in G1 and 20% in G2 had good oral language (p = 0.02). One child in G1 had no improvement after implantation.

CONCLUSIONS

No major complication was seen. Perceptive and linguistic results were variable and depended on the type of the deafness. In progressive deafness, the perceptive and linguistic result are expected to be good. In congenital deafness, the results are more variable.

Pediatric Cochlear Implant Patient Performance as a Function of Age at Implantation

OBJECTIVE

The objective of this study was to examine the effect that age at implantation has on performance of children who received multichannel cochlear implants.

STUDY DESIGN

This is a retrospective study of 295 children who were broken down into 5 age groups based on age at implantation: 1-3 years, 3-5 years, 5-7 years, 7-9 years, and 9-11 years. Speech perception test scores obtained 12, 24, and 36 months postactivation were compared for the 5 groups using repeated-measures analysis of variance.

SETTING

This study was carried out at a tertiary academic medical center.

PATIENTS

Subjects consisted of 295 children who ranged in age from 12 months to 10 years 11 months at the time they obtained their cochlear implant.

INTERVENTION

All patients received their cochlear implant at a single implant facility.

MAIN OUTCOME MEASURES

Performance on several speech perception tests was compared 12, 24, and 36 months postactivation. Performance was evaluated as a function of age at implantation.

RESULTS

Patients in all 5 groups demonstrated improved scores when compared with scores obtained preoperatively with hearing aids. Repeated-measures analysis of variance (ANOVA) revealed a significant group by time interaction for 3 of the 5 measures. For all three of these measures, children implanted at younger ages demonstrated greater gains in speech perception over time than children implanted at older ages.

CONCLUSIONS

These results are in agreement with those of previous studies indicating that early implantation facilitates improved development of speech perception skills in profoundly deaf children.

Early identification and cochlear implantation: critical factors for spoken language development

Documentation is lacking regarding the ability of congenitally deaf children to attain age-appropriate spoken language skills using a cochlear implant, and how early implantation must occur if such development is to be possible. Spoken language data are presented for infants who underwent implantation at 18 months of age or younger. Additional data are used to compare outcomes among children who differed in age at implantation. Data collected at Carle Clinic and Foundation Hospital were reviewed for 47 consecutively implanted children ranging in age from 9 to 48 months at implantation. These data were analyzed and compared by age-at-implantation groupings for speech perception skills, communication mode, and spoken language abilities. The groups differed dramatically in abilities. The best outcomes occurred in children who underwent implantation at or before 18 months of age. Several of these infants demonstrated age-appropriate spoken language skills. We conclude that early implantation is desirable. Children who undergo implantation as infants may develop language skills commensurate with those of their hearing peers.