Cochlear implants in children deafened by congenital cytomegalovirus and matched Connexin 26 peers

Congenital cytomegalovirus infection: the state of the art and future perspectives

Congenital cytomegalovirus (cCMV) infection is the most common congenital infection, with an estimated incidence of approximately one in 200 infants in high-income settings. Approximately one in four children may experience life-long consequences, including sensorineural hearing loss and neurodisability. Knowledge regarding prevention, diagnosis, and treatment increased in the recent years, but some challenges remain. In this review, we tried to summarize the current knowledge on both the obstetrical and pediatric areas, while also highlighting controversial aspects and future perspectives. There is a need to enhance awareness among the general population and pregnant women through specific information programs. Further research is needed to better define the classification of individuals at birth and to have a deeper understanding of the long-term outcomes for so defined children. Finally, the availability of valaciclovir medication throughout pregnancy, where appropriate, has prompted the assessment of a universal serological antenatal screening. It is recommended to establish a dedicated unit for better evaluation and management of both mothers and children.

Hearing Instability in Children with Congenital Cytomegalovirus: Evidence and Neural Consequences

OBJECTIVE/HYPOTHESIS

Sensorineural hearing loss (SNHL) is a common sequela of congenital cytomegalovirus (cCMV), potentially exacerbating neurocognitive delay. The objectives of this study were to assess: (1) age at which SNHL in children with cCMV; (2) stimulability of the auditory system in children with cCMV following cochlear implantation (CI); and (3) whether features of magnetic resonance imaging (MRI) potentially are predictive of hearing outcomes.

METHODS

In this retrospective study of a prospectively acquired cohort, 123 children with cCMV who were referred for hearing loss at a single tertiary referral hospital over 20 years were compared with an unmatched comparative group of 90 children with GJB2-related deafness. Outcome measures were results of newborn hearing screening (NHS), behavioral audiograms, and, in a subgroup of cochlear implant (CI) users, responses from the auditory nerve and brainstem evoked by CI at initial activation, as well as lesional volume of FLAIR-hyperintense signal alterations on MRI.

RESULTS

All but 3 of 123 children with cCMV had confirmed and persistent SNHL. At birth, 113 children with cCMV underwent NHS, 31 (27%) passed in both ears and 23 (20%) passed in one ear (no NHS data in 10 children). At the first audiologic assessment, 32 of 123 (26%) had normal hearing bilaterally; 35 of 123 (28%) had unilateral SNHL; and 57 of 123 (46%) had bilateral SNHL. More than half (67 of 123, 54%) experienced hearing deterioration in at least one ear. Survival analyses suggested that 60% of children who developed SNHL did so by 2.5 years and 80% by 5 years. In the children who passed NHS in one or both ears, 50% developed hearing loss by 3.5 years in the ear, which passed unilaterally (n = 23 ears), and 50% by 5 years in bilateral passes (n = 62 ears). Hearing loss was significant enough in all but one child with isolated high-frequency loss for rehabilitation to be indicated. Hearing thresholds in individual ears were in the CI range in 83% (102 of 123), although duration of deafness was sufficient to preclude implantation at our center in 13 children with unilateral SNHL. Hearing aids were indicated in 16% (20 of 123). Responses from the auditory nerve and brainstem to initial CI stimulation were similar in children with cCMV-related SNHL compared with GJB2-related SNHL. Characteristic white matter changes on MRI were seen in all children with cCMV-related SNHL (n = 91), but the lesion volume in each cortical hemisphere did not predict degree of SNHL.

CONCLUSIONS

cCMV-related SNHL is often not detected by NHS but occurs with high prevalence in early childhood. Electrophysiological measures suggest equivalent stimulability of the auditory nerve and brainstem with CI in children with cCMV and GJB2-related SNHL. Hyperintense white matter lesions on FLAIR MRI are consistently present in children with cCMV-related SNHL but cannot be used to predict its time course or degree. Combined, the data show early and rapid deterioration of hearing in children with cCMV-related SNHL with potential for good CI outcomes if SNHL is identified and managed without delay. Findings support universal newborn screening for cCMV followed by careful audiological monitoring.

LEVEL OF EVIDENCE

3 Laryngoscope, 2022.

Early Identification and Management of Congenital Cytomegalovirus

Congenital cytomegalovirus (cCMV) is the most common nongenetic cause of sensorineural hearing loss. Despite its prevalence, universal screening for cCMV is not currently performed. Hearing loss caused by cCMV is most often severe to profound, often bilateral, and may be fluctuating or progressive. Infants with hearing loss at birth and confirmed cCMV might benefit from antiviral therapy. Roughly half of hearing loss cases owing to cCMV are delayed in onset, and consequently, these children pass newborn hearing screening. Children with cCMV require close audiologic monitoring, require appropriate management with hearing aids, and should be monitored for cochlear implant candidacy.

Outcome of cochlear implantation in children with congenital Cytomegalovirus infection: A retrospective case control study

INTRODUCTION

To date, cCMV represents the most frequent non-genetic congenital cause of permanent sensorineural hearing loss (SNHL) in childhood and the leading infectious cause of developmental and neurologic disabilities. The aim of this paper is to describe the outcome of cochlear implantation in children affected by severe-to-profound sensorineural hearing loss, due to a symptomatic or asymptomatic cCMV infection, particularly comparing their performance results to that of matched mutated Connexin 26 (Cx26) implanted patients.

METHODS

Retrospective case control study. The clinical data of symptomatic cCMV and asymptomatic cCMV patients were collected and compared to those of Cx26 patients matched for age and pre-CI (cochlear implant) linguistic category; all subjects were affected by bilateral severe-to-profound SNHL and were treated by CI and speech therapy rehabilitation. The Speech Perception Category, the language stage and the linguistic level scores, at 6 months, 1 year, and 3-4 years after CI of the three groups (symptomatic cCMV, asymptomatic cCMV and Cx26 mutation) were collected and compared.

RESULTS

Statistical analysis did not show any significant difference in pre-CI perception category and linguistic level among the three groups; the symptomatic cCMV group showed a statistically worse performance of the language stage over time (p = 0.017).

CONCLUSIONS

Our data support that children affected by cCMV have improved language abilities over time, although the symptomatic cCMV group achieved a lower language stage 3-4 years after CI compared to the asymptomatic cCMV and Cx26 mutation groups. Nonetheless, to date, CI supported by speech therapy can be considered an effective intervention for children affected by cCMV-related severe-to-profound hearing loss.

Long-term results of cochlear implantation in children with congenital single-sided deafness

Purpose

The purpose of this retrospective study was to investigate the outcome and critical age of cochlear implantation in congenital single-sided deafness (SSD).

Methods

11 children with congenital SSD were implanted with a cochlear implant (CI). Auditory performance was measured through the results of speech discrimination, subjective assessment by the Categories of auditory performance (CAP) score, the Speech, Spatial and Qualities scale questionnaire (SSQ) and the German version of the IOI-HA [Internationales Inventar zur Evaluation von Hörgeräten (IIEH, version for CI)].

Results

Long-term follow-up [median: 3 years and 5 months (3;5 years)] revealed that nine children use their CI (> 8 h/day) and two became nonusers. In children aged below 3;2 years at surgery, there was a substantial long-term increase in speech discrimination and subjective benefit. Children over 4;4 years of age at CI surgery improved partially in audiological/subjective measurements. Among children above 5 years, the SSQ score did not improve despite further slight improvement in speech discrimination long-term.

Conclusion

Our data suggest a critical age for CI surgery below 3 years in children with congenital SSD for successful hearing rehabilitation. It is mandatory to identify children with SSD as early as bilaterally deaf children.

Cytomegalovirus infection during pregnancy: state of the science

Cytomegalovirus is the most common congenital infection, affecting 0.5-2% of all live births and the main nongenetic cause of congenital sensorineural hearing loss and neurological damage. Congenital cytomegalovirus can follow maternal primary infection or nonprimary infection. Sensorineurological morbidity is confined to the first trimester with up to 40-50% of infected neonates developing sequelae after first-trimester primary infection. Serological testing before 14 weeks is critical to identify primary infection within 3 months around conception but is not informative in women already immune before pregnancy. In Europe and the United States, primary infection in the first trimester are mainly seen in young parous women with a previous child younger than 3 years. Congenital cytomegalovirus should be evoked on prenatal ultrasound when the fetus is small for gestation and shows echogenic bowel, effusions, or any cerebral anomaly. Although the sensitivity of routine ultrasound in predicting neonatal symptoms is around 25%, serial targeted ultrasound and magnetic resonance imaging of known infected fetuses show greater than 95% sensitivity for brain anomalies. Fetal diagnosis is done by amniocentesis from 17 weeks. Prevention consists of both parents avoiding contact with body fluids from infected individuals, especially toddlers, from before conception until 14 weeks. Candidate vaccines failed to provide more than 75% protection for >2 years in preventing cytomegalovirus infection. Medical therapies such as cytomegalovirus hyperimmune globulins aim to reduce the risk of vertical transmission but 2 randomized controlled trials have not found any benefit. Valaciclovir given from the diagnosis of primary infection up to amniocentesis decreased vertical transmission rates from 29.8% to 11.1% in the treatment group in a randomized controlled trial of 90 pregnant women. In a phase II open-label trial, oral valaciclovir (8 g/d) given to pregnant women with a mildly symptomatic fetus was associated with a higher chance of delivering an asymptomatic neonate (82%), compared with an untreated historical cohort (43%). Valganciclovir given to symptomatic neonates is likely to improve hearing and neurological symptoms, the extent of which and the duration of treatment are still debated. In conclusion, congenital cytomegalovirus infection is a public health challenge. In view of recent knowledge on diagnosis and pre- and postnatal management, health care providers should reevaluate screening programs in early pregnancy and at birth.

Genotype-Phenotype Correlation for Predicting Cochlear Implant Outcome: Current Challenges and Opportunities

The use and utility of cochlear implantation has rapidly increased in recent years as technological advances in the field have expanded both the efficacy and eligible patient population for implantation. This review aims to serve as a general overview of the most common hearing disorders that have favorable auditory outcomes with cochlear implants (CI). Hearing loss in children caused by congenital cytomegalovirus infection, syndromic conditions including Pendred Syndrome, and non-syndromic genetic conditions such as hearing impairment associated with GJB2 mutations have shown to be successfully managed by CI. Furthermore, cochlear implantation provides the auditory rehabilitation for the most common etiology of hearing loss in adults and age-related hearing loss (ARHL) or presbycusis. However, in some cases, cochlear implantation have been associated with some challenges. Regarding implantation in children, studies have shown that sometimes parents seem to have unrealistic expectations regarding the ability of CI to provide auditory rehabilitation and speech improvement. Given the evidence revealing the beneficial effects of early intervention via CI in individuals with hearing disorders especially hearing loss due to genetic etiology, early auditory and genetic screening efforts may yield better clinical outcomes. There is a need to better understand genotype-phenotype correlations and CI outcome, so that effective genetic counseling and successful treatment strategies can be developed at the appropriate time for hearing impaired individuals.

Hearing and speech benefits of cochlear implantation in children: A review of the literature

Cochlear implantation is a safe and reliable treatment for children with severe to profound hearing loss. The primary benefit of these medical devices in children is the acquisition of hearing, which promotes development of spoken language. The present paper reviews published literature demonstrating predictive effects of a number of factors on acquisition of hearing development and speech recognition. Of the many variables that contribute to an individual child's development after implantation, age at implantation, the presence of medical comorbidities, social determinants of health, and the provision of bilateral versus unilateral hearing are those that can vary widely and have consistently shown clear impacts. Specifically, age of implantation is crucial to reduce effects of deafness on the developing auditory system and capture the remarkable plasticity of early development. Language development after cochlear implantation requires therapy emphasizing hearing and oral communication, education, and other support which can be influenced by known social determinants of health; specifically, outcomes in children decline with reductions in socioeconomic status and levels of parental education. Medical co-morbidities also slow rates of progress after cochlear implantation. On the other hand, benefits of implantation increase in children who are provided with access to hearing from both ears. In sum, cochlear implants promote development of hearing in children and the best outcomes are achieved by providing early access to sound in both ears. These benefits can be limited by known social determinants of health which restrict access to needed support and medical comorbidities which add further complexity in care and outcome.

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.

The Natural History and Rehabilitative Outcomes of Hearing Loss in Congenital Cytomegalovirus: A Systematic Review

OBJECTIVE

The purpose of this study was to examine the literature regarding the natural history and rehabilitative outcomes of sensorineural hearing loss from congenital cytomegalovirus infections.

DATA SOURCES AND STUDY ELIGIBILITY CRITERIA

A systematic search was performed in PubMed, PsychINFO, CINAHL, and Web of Science to identify peer-reviewed research. Eligible studies were those containing original peer-reviewed research in English addressing either the natural history or rehabilitative outcomes of sensorineural hearing loss (SNHL) in congenital cytomegalovirus (cCMV).

STUDY APPRAISAL AND SYNTHESIS METHODS

Two investigators independently reviewed all articles and extracted data. Bias was assessed using the Cochrane Collaboration's tool and the Newcastle-Ottawa Assessment Scale.

RESULTS

Thirty-six articles were reviewed. Universal screening identifies 0.2 to 1% of newborns with cCMV infection. SNHL ranged from 8 to 32% of infants and was more prevalent in symptomatic versus asymptomatic cases. Nine to 68% of hearing loss occurs in a late or delayed fashion. In 7 to 71% of cases hearing loss is progressive. Cochlear implantation (CI) is a viable option for patients with cCMV associated hearing loss and leads to improvements in hearing and language. There is limited literature comparing rehabilitation outcomes in cCMV and non-cCMV CI recipients.

CONCLUSION

Late onset and progressive hearing loss is seen in children who develop hearing loss from cCMV. Frequent audiologic follow-up is necessary considering the natural history of cCMV hearing loss. Universal screening should be pursued due to the number of asymptomatic children, at birth, who develop late onset/delayed hearing loss. CI is an effective means of improving speech and language in this population.

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.

Unilateral congenital hearing loss in children: Challenges and potentials

The estimated incidence of sensorineural hearing impairment (>40 dB HL) at birth is 1.86 per 1000 newborns in developed countries and 30-40% of these are unilateral. Profound sensorineural unilateral hearing impairment or single sided deafness (SSD) can be treated with a cochlear implant. However, this treatment is costly and invasive and unnecessary in the eyes of many. Very young children with SSD often do not exhibit language and cognitive delays and it is hard to imagine that neurocognitive skills will present difficulties with one good ear. In the current paper we review the most recent evidence on the consequences of unilateral hearing impairment for auditory and neurocognitive factors. While data of both adults and children are discussed, we focus on developmental factors, congenital deafness and a window of opportunity for intervention. We discuss which etiologies qualify for a cochlear implant and present our multi-center prospective study on cochlear implants in infants with one deaf ear. The large, state-of-the art body of research allows for evidence-based decisions regarding management of unilateral hearing loss in children.

Prediction of the Outcome of Cochlear Implantation in the Patients with Congenital Cytomegalovirus Infection based on Magnetic Resonance Imaging Characteristics

The goal of this study was to elucidate radiologic biomarker that can predict the outcome of cochlear implantation (CI) in congenital cytomegalovirus (cCMV) related deafness. A retrospective survey of speech perception after CI and an evaluation of brain magnetic resonance imaging (MRI) findings were performed in 10 cochlear implantees with cCMV-related prelingual deafness. Specifically, a special attention was paid to the degree of white matter (WM) abnormality shown in brain MRI, which was used to divide our cohort into two groups: The mild and severe pathology groups. Age-matched prelingual deaf patients with idiopathic sensorineural hearing loss were selected as controls. Subjects in mild pathology groups showed higher a Category of Auditory Performance (CAP) score (5.2 ± 0.8) than those with severe pathologies (3.4 ± 1.5) (P = 0.041). Importantly, speech performance from subjects with mild pathology was comparable to that of the control group (mean CAP score of 5.2 ± 0.8 vs. 5.1 ± 1.2) (P = 0.898). Mild pathologies related to the limited WM lesion in MRI not accompanied by severe MRI pathologies, such as diffuse WM abnormality, myelination delay, ventriculomegaly, migration abnormality, and cerebellar hypoplasia, can be tolerated and do not adversely affect the CI outcome in cCMV deafness.

Long-term Outcomes of Cochlear Implantation in Children With Congenital Cytomegalovirus Infection

OBJECTIVE

To investigate the role of the developmental delay often observed in children with congenital cytomegalovirus (CMV) infection on the improvement of language understanding after cochlear implantation (CI).

STUDY DESIGN

Retrospective chart review.

PATIENTS

Sixteen children with severe and/or profound hearing loss due to congenital CMV infection (CMV group) and 107 congenitally deaf children (168 ears) without CMV infection as the cause of deafness (non-CMV group). Mean age at which patients underwent CI was 2.9 years in both groups. The mean follow-up period was 7.8 versus 8.2 years, respectively.

INTERVENTIONS/MAIN OUTCOME MEASURES

The Enjoji Scale of Infant Analytical Development was used to evaluate/compare pre- and postoperative hearing level, word recognition score, speech discrimination score, and language production and perception skills. The Picture Vocabulary Test-Revised was used to assess vocabulary understanding skill. Correlation between the final vocabulary understanding skill assessment and several factors was also examined.

RESULTS

Improvement in hearing thresholds (mean: 106.0 dB) was greater after the first CI, (27-45 dB; mean: 33.8 dB) compared with hearing aid (48-74 dB; mean: 63.1 dB). Similarly, language perception and production were better in the CMV group. However, in the long term, differences between good and poor cases became prominent, especially in children with motor or cognitive delay and brain abnormalities who performed poorly in the CMV group.

CONCLUSION

Long-term language perception and production after CI were overall satisfactory in congenital CMV-deafened children. CI was effective, particularly in the absence of CMV-induced disorders. However, this effectiveness was limited in those with motor or cognitive delay.

Disparities in access to pediatric hearing health care

PURPOSE OF REVIEW

There are significant disparities in care facing children with hearing loss. The objective of this review is to assess the current disparities in pediatric hearing healthcare delivery, describe the barriers of efficient and effective pediatric hearing health care, and explore the innovations to improve pediatric hearing healthcare delivery.

RECENT FINDINGS

Children with hearing loss from certain geographic regions or ethnic background are significantly delayed in diagnosis and treatment. Multiple patient characteristics (presentation of hearing loss), parental factors (insurance status, socioeconomic status, educational status, and travel distance to providers), and provider barriers (specialist shortage and primary care provider challenges) prevent the delivery of timely hearing health care. Advances, such as improved screening programs and the expansion of care through remote services, may help to ameliorate these disparities.

SUMMARY

Timely identification and treatment of pediatric hearing loss is critical to prevent lifelong language complications. Children from vulnerable populations, such as rural residents, face significant disparities in care. Careful assessment of these barriers and implementation of culturally acceptable interventions are paramount to maximize communication outcomes of children with hearing loss.

Audiovestibular consequences of congenital cytomegalovirus infection

Congenital cytomegalovirus (CMV) infection is the second most frequent cause of mental retardation and sensorineural hearing loss, after genetic factors. Recently, pediatric forensic and fetopathological studies have led to progress in understanding the pathophysiological mechanisms underlying the various neurosensory sequelae. Thanks to the identification of certain prognostic factors of hearing loss, therapeutic protocols based on antiviral molecules are now proposed for target populations. This treatment has shown efficacy in limiting hearing threshold deterioration and even, in some cases, seems to provide partial recovery of hearing in symptomatic congenitally infected CMV neonates. However, optimal treatment duration and administration modalities are not clearly defined. This article reviews recent data concerning audiovestibular sequelae and their management in children congenitally infected by CMV.