Is deafness etiology important for prediction of functional outcomes in pediatric cochlear implantation?

Predictors of Early Language Outcomes in Children with Connexin 26 Hearing Loss across Three Countries

GJB2-associated hearing loss (GJB2-HL) is the most common genetic cause of hearing loss in children. However, little is known about the clinical characteristics and early language outcomes in population-oriented samples including children with different degrees of hearing loss. Insight into these characteristics are relevant for the counselling of parents. Our sample consisted of 66 children at approximately 2 years of age (17–32 months) with bilateral hearing loss due to GJB2 from three population-based cohorts in Austria, Australia and the Netherlands. Predictors of early vocabulary, including demographic, audiological, genetic and intervention variables and the role of medical comorbidities and nonverbal cognition were examined. The vocabulary scores of children with GJB2-HL were approximately 0.7 standard deviations (SDs) below the norms of children with typical hearing. Age at access to family-centered early intervention and first-born position among siblings predicted language outcomes, whereas the degree of hearing loss and genetic subtype were not significantly correlated with expressive vocabulary. In children with GJB2-HL, early access to family-centered early intervention significantly affected language outcomes at the age of two.

Role of Targeted Next Generation Sequencing in the Etiological Work-Up of Congenitally Deaf Children

OBJECTIVES

The purpose of this study is to report the results of a comprehensive etiological work-up for congenitally deaf children including targeted next generation sequencing.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

Fifty children with congenital, bilateral profound hearing loss (HL) (>90 dBnHL).

INTERVENTIONS

Etiological work-up included testing for pathogenic variants in GJB2, a phenotype driven genetic analysis, screening for congenital infections and imaging. When no etiology could be found, comprehensive genetic testing was performed using a HL gene panel including 45 syndromic and 96 non-syndromic HL genes.

RESULTS

Eleven patients carried bi-allelic pathogenic variants in GJB2. Phenotype driven genetic analysis identified two homozygous KCNQ1 patients (Jervell and Lange Nielsen syndrome) and one heterozygous CHD7 patient (CHARGE syndrome). One patient was diagnosed with achondroplasia and one had a clinical diagnosis of Waardenburg syndrome. A deafness gene panel evaluated 16 patients. In 12 out of 16, we identified a pathogenic (n = 12) or likely pathogenic (n = 2) variant and one variant of unknown significance (VUS). A definite diagnosis of non-syndromic or syndromic HL was made in 18 and seven patients, respectively. Non-genetic causes were congenital cytomegalovirus infection (n = 11), anatomic abnormalities (n = 2), neurological/metabolic/polymalformative conditions (n = 3), meningitis (n = 1), and auditory neuropathy (n = 1).

CONCLUSIONS

A definite genetic cause was found in 25 (50%) of congenital, bilaterally deaf children. Our data show that implementation of a gene panel improves the diagnostic yield for etiological work-up of congenital profound HL to 86%. Identification of the etiology of congenital HL may contribute to predicting outcomes of cochlear implantation.

Language outcome in children with congenital hearing impairment: The influence of etiology

OBJECTIVES

To investigate the possible association between the etiology of hearing impairment (HI) and language outcome in children with congenital HI after an early medical-technical intervention and three years of AVT.

METHODS

A retrospective, two-center study was conducted of 53 patients who were divided in four categories of etiology (degeneratio labyrinthi acustici (DLA) congenita hereditaria, DLA congenita non specificata, DLA congenita postinfectiosa and auditory neuropathy). Language outcome was assessed by examining receptive vocabulary (Peabody Picture Vocabulary Test, PPVT-4), receptive language (Reynell test) and productive language (the Danish 'Viborgmaterialet'). All tests were conducted 1, 2 and 3 years after the children received their hearing device. Test scores were calculated from the child's chronological age. Analysis of possible associations was performed using Fisher's exact test and McNemar's test was conducted to examine possible differences between each year of testing for every speech-language test. Subsequently, univariate analyses were performed to search for other possible covariates associated with language outcome.

RESULTS

No significant associations were found between the etiology of the HI and the language outcome of children with HI after 1 year of AVT (PPVT, p = 0,234; Reynell, p = 0,845; Viborgmaterialet, p = 0,667), neither after 2 years of AVT (PPVT, p = 0,228; Reynell, p = 0,172; Viborgmaterialet, p = 0,659) nor after 3 years of AVT (PPVT, p = 0,102; Reynell, p = 0,512 Viborgmaterialet, p = 0,580). Some significant associations were found between language outcome and the type of hearing device and between language outcome and additional disabilities, however no strong evidence was found.

CONCLUSION

Most children with congenital HI developed a comparable level of speech and language regardless of the etiology of their HI. This study highlights the interest of further research using objective assessments techniques in a larger and more homogeneous population. If the findings from this study will be confirmed in future studies, this will have a clinical and societal impact regarding the diagnostics of HI.

Long Term Speech Perception Outcomes of Cochlear Implantation in Gap Junction Protein Beta 2 Related Hearing Loss

BACKGROUND AND OBJECTIVES

The mutation of the gap junction protein beta 2 (GJB2) gene is the predominant cause of autosomal recessive non-syndromic hearing loss. The purpose of this study was to evaluate the speech perception outcome after cochlear implantation according to the presence of a GJB2 mutation.

SUBJECTS AND METHODS

During the period from March 2004 to February 2005, 38 patients underwent cochlear implantation at Asan Medical Center. Genetic factors and speech perception were evaluated in all subjects, and the patients were grouped according to the presence of a GJB2 mutation. The two groups were carefully matched according to the age at cochlear implantation. We analyzed four mutations in the GJB2 gene: 35delG, 167delT, 235delC, and E114G. Speech perception outcomes were measured using the open set, 1 and 2 syllables, the comprehension test, the Meaningful Auditory Integration Scale, the categories of auditory performance, and the Speech Intelligibility Rating scores. The evaluations were performed before the operation, 6 and 12 months thereafter, and then annually up to nine years after cochlear implantation.

RESULTS

Fifteen patients had bi-allelic GJB2 mutations (11 with E114G and 4 with 235delC), whereas the remaining 23 had wild type alleles. For the age-matched analysis, 14 patients were selected and divided into two groups of 7 subjects each: GJB2 mutation and no mutation (i.e., deafness of unknown origin). Overall, all patients showed improvement of speech perception outcome after cochlear implantation. There was no difference in the improvement between patients with and without GJB2 mutations at the 5-year and 9-year follow up. The pattern of improvement throughout the duration of the follow-up also showed no difference between the two groups.

CONCLUSIONS

Similar outcomes of speech perception are expected after cochlear implantation in pediatric patients with or without GJB2 mutation.

Predictive Value of GJB2 Mutation Status for Hearing Outcomes of Pediatric Cochlear Implantation

Objective To systematically review and quantify current evidence regarding the association of GJB2 mutation status with outcomes of pediatric cochlear implantation. Data Sources PubMed, Embase, and the Cochrane Library were searched for "GJB2,""pediatric hearing loss," and "cochlear implantation" and their synonyms, with no language restrictions, until December 2, 2015. Review Methods Studies were included that investigated the status of GJB2 mutation and its predictive value for outcomes of pediatric cochlear implantation. Speech recognition scores, Infant-Toddler Meaningful Auditory Integration Scale, Speech Intelligibility Rating, and Categorized Auditory Performance were pooled using weighted mean differences, and a 95% confidence interval. Results Eighteen studies met the inclusion criteria. The differences between GJB2-related deafness and non- GJB2-related deafness due to unidentified causes and other types of genetic deafness without additional disabilities were not statistically significant ( P = .15 and P = .30, respectively); however, the difference between GJB2-related deafness and acquired hearing loss due to environmental etiologies was statistically significant and favored GJB2-related deafness ( P = .03). Conclusion GJB2-related deafness leads to significantly better cochlear implantation outcomes when compared with acquired deafness caused by environmental etiologies. However, GJB2 mutation is not associated with a significantly better prognosis when compared with those whose deafness results from either nonsyndromic hearing loss of unknown origin or other types of genetic mutations in the absence of other neurologic deficits.

Intelligence development of pre-lingual deaf children with unilateral cochlear implantation

OBJECTIVE

The present study aims to test whether deaf children with unilateral cochlear implantation (CI) have higher intelligence quotients (IQ). We also try to find out the predictive factors of intelligence development in deaf children with CI.

METHODS

Totally, 186 children were enrolled into this study. They were divided into 3 groups: CI group (N = 66), hearing loss group (N = 54) and normal hearing group (N = 66). All children took the Hiskey-Nebraska Test of Learning Aptitude to assess the IQ. After that, we used Deafness gene chip, Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR) methods to evaluate the genotype, auditory and speech performance, respectively.

RESULTS

At baseline, the average IQ of hearing loss group (HL), CI group, normal hearing (NH) group were 98.3 ± 9.23, 100.03 ± 12.13 and 109.89 ± 10.56, while NH group scored higher significantly than HL and CI groups (p < 0.05). After 12 months, the average IQ of HL group, CI group, NH group were99.54 ± 9.38,111.85 ± 15.38, and 112.08 ± 8.51, respectively. No significant difference between the IQ of the CI and NH groups was found (p > 0.05). The growth of SIR was positive correlated with the growth of IQ (r = 0.247, p = 0.046), while no significant correlation were found between IQ growth and other possible factors, i.e. gender, age of CI, use of hearing aid, genotype, implant device type, inner ear malformation and CAP growth (p > 0.05).

CONCLUSIONS

Our study suggests that CI potentially improves the intelligence development in deaf children. Speech performance growth is significantly correlated with IQ growth of CI children. Deaf children accepted CI before 6 years can achieve a satisfying and undifferentiated short-term (12 months) development of intelligence.

What can we expect of normally-developing children implanted at a young age with respect to their auditory, linguistic and cognitive skills?

As a result of neonatal hearing screening and subsequent early cochlear implantation (CI) profoundly deaf children have access to important information to process auditory signals and master spoken language skills at a young age. Nevertheless, auditory, linguistic and cognitive outcome measures still reveal great variability in individual achievements: some children with CI(s) perform within normal limits, while others lag behind. Understanding the causes of this variation would allow clinicians to offer better prognoses to CI candidates and efficient follow-up and rehabilitation. This paper summarizes what we can expect of normally developing children with CI(s) with regard to spoken language, bilateral and binaural auditory perception, speech perception and cognitive skills. Predictive factors of performance and factors influencing variability are presented, as well as some novel data on cognitive functioning and speech perception in quiet and in noise. Subsequently, we discuss technical and non-technical issues which should be considered in the future in order to optimally guide the child with profound hearing difficulties. This article is part of a Special Issue entitled <Lasker Award>.