Long-term treatment outcomes in children with auditory neuropathy spectrum disorder (ANSD)

Systematic Literature Review and Early Benefit of Cochlear Implantation in Two Pediatric Auditory Neuropathy Cases

Approximately 1 in 10 children with hearing loss is affected by auditory neuropathy spectrum disorder (ANSD). People who have ANSD usually have great difficulty understanding speech or communicating. However, it is possible for these patients to have audiograms that may indicate profound hearing loss up to normal hearing. This disorder is prognosed with positive, intact or present otoacoustic emissions (OAE) and/or cochlear microphonics (CM) as well as abnormal or absent auditory brainstem responses (ABR). Treatment methods include conventional hearing aids as well as cochlear implants. Cochlear implants (CI) usually promise better speech understanding for ANSD patients. We performed a systematic literature review aiming to show what improvements can effectively be achieved with cochlear implants in children with ANSD and compare this with our experience with two cases of ANSD implanted at our clinic. The retrospective review of two young CI patients diagnosed with ANSD during infancy demonstrated improvements over time in speech development communicated by their parents.

Establishment of Reference Values for Early Auditory Preverbal Skills of Children with Cochlear Implants

Auditory and verbal abilities of children with early cochlear implant (CI) surgery usually take some time to develop, and a reference index of early development for horizontal comparisons is urgently needed to guide the mapping process and adjust rehabilitation programs. Therefore, the aim of this study was to establish a reference value for early auditory preverbal skills development in children with CI and investigate the developmental curve and influencing factors for these children. The LittlEARS® Auditory Questionnaire (LEAQ) scores of 287 eligible Chinese participants were obtained at 1, 2, 3, 6, 9, 12, 18, 24, 28, and 36 months interval after CI activation. The median and standard deviation of the LEAQ score of each hearing stage for these children with different activation ages were calculated to establish the reference values. Quadratic regression was conducted to fit the expected developmental curve of the LEAQ score (y=-0.057x2+2.55x+5.45 [0 to 20 months]). With a linear mixed-effects model, we found that the receptive auditory behavior increased rapidly after CI activation, while expressive language skills developed at a steady rate. We also found that the following factors all significantly influenced the LEAQ: the duration of CI use, the development quotient, age of implantation and activation, and the presence of large vestibular aqueduct syndrome or auditory neuropathy spectrum disorder. The reference values and the expected developmental curve for the LEAQ in children with CI established by the present study provides guidance to clinicians and parents as well as realistic expectations regarding language and speech outcomes.

Determination of language performance by discriminant function analysis in Mandarin-speaking preschoolers with auditory neuropathy spectrum disorder

OBJECTIVE

Characteristics of the audiological performance of children with auditory neuropathy spectrum disorder (ANSD) have been identified; however, studies regarding factors influencing their language development, especially those related to aural-oral rehabilitation, are relatively few. This study aimed to investigate classification functions among the factors regarding audiological, interventional (rehabilitation) and demographic variables that can help determine group membership in language performance for Mandarin-speaking preschoolers with ANSD.

METHODS

Children with ANSD aged 3-6 years (n = 27) enrolled in an auditory-verbal therapy were recruited. The combination of factors that could be used to predict memberships of children regarding whether they achieved age-appropriate language performance or were at risk of language delay were explored using discriminant function analysis.

RESULTS

Maternal education level, age at initial hearing aid fitting, and duration of rehabilitation were all significant factors in predicting the membership of children with ANSD and whether they could achieve an age-appropriate language level or were at risk for language delay. The correct rate for predicting the memberships ranged from 70.4% to 83.3%. Duration of rehabilitation accounted for the greatest effect on discriminant membership regarding achieving age-appropriate language performance and being at risk of language delay. Effect of maternal education level tended to centralize on language comprehension.

CONCLUSIONS

Differences were observed in the quantifiable effects of predictors in discriminant functions for language ability domains. Except for using suitable hearing devices, adequate duration of enrollment in aural and oral rehabilitation would also be important for children with ANSD to develop better language abilities.

[Auditory neuropathy and prematurity: modern view of the issue (literature review)]

Auditory neuropathy spectrum disorder (ANSD) is a specific auditory disorder caused by dysfunction of periphery part of the auditory system, in which the function of the outer hair cells is preserved, but the afferent input at the cochlear level suffers due to the pathology of the inner hair cells, neurons of the spiral ganglion and/or the auditory nerve, as well as synaptic contact between them. As a result, a specific condition is formed, in which a patient's otoacoustic emissions and/or cochlear microphonics are present, auditory brainstem responses are abnormal or absent, the discrepancy between the hearing level and the electrophysiological data, poor speech perception which may not correlate with the hearing thresholds. ANSD is a multifactorial disease. One of the main risk factors is perinatal pathology and, in particular, prematurity. The possible factors associated with prematurity that provoke the onset of the disease, features of the pathogenesis, clinical and audiological peculiarities of ANSD in premature infants, contemporary approaches to the habilitation of such patients are discussed in the article. The necessity of an individual, patient-oriented approach to the treatment of premature infants with ANSD is substantiated; such an approach should be based both on the genesis of the disorder, taking into account possible points of lesion in the auditory system, and the developmental peculiarities of a premature baby considering the presence of concomitant diseases associated with prematurity. In the article attention is focused on the main directions of habilitation work with such children, including a multidisciplinary approach, regular careful monitoring of the auditory, speech and language skills, intensive psychological and speech therapist support, the choice of an adequate way of intervention and its improvement as necessary.

The audiovestibular profile of Brown-Vialetto-Van Laere syndrome

BACKGROUND

Brown-Vialetto-Van Laere syndrome, a rare disorder associated with motor, sensory and cranial nerve neuropathy, is caused by mutations in riboflavin transporter genes SLC52A2 and SLC52A3. Hearing loss is a characteristic feature of Brown-Vialetto-Van Laere syndrome and has been shown in recent studies to be characterised by auditory neuropathy spectrum disorder.

METHOD

This study reports the detailed audiovestibular profiles of four cases of Brown-Vialetto-Van Laere syndrome with SLC52A2 and SLC52A3 mutations. All of these patients had auditory neuropathy spectrum disorder.

RESULTS

There was significant heterogeneity in vestibular function and in the benefit gained from cochlear implantation. The audiological response to riboflavin therapy was also variable, in contrast to generalised improvement in motor function.

CONCLUSION

We suggest that comprehensive testing of vestibular function should be conducted in Brown-Vialetto-Van Laere syndrome, in addition to serial behavioural audiometry as part of the systematic examination of the effects of riboflavin.

Clinical characteristics of patients with unilateral auditory neuropathy

OBJECTIVE

To analyze the clinical characteristics of patients with unilateral auditory neuropathy (UAN), and to provide guidance for future clinical diagnosis and research.

METHODS

Patients who were clinically diagnosed with UAN from 2004 to 2019 were included. Clinical characteristics, audiological features, imaging findings, genetic test results and management effect were summarized and followed.

RESULTS

A total of 44 patients [mean age, 4.35 ± 4.39 years; 22 (50.00%) males and 22 (50.00%) females] were enrolled for analyses. Among the 38 patients who were tested by pure-tone or behavioral audiometry, the degree of hearing loss of the affected ear was characterized as mild in 2 ears (5.26%), moderate in 5 (13.16%), severe in 9 (23.68%) and profound in 22 (57.89%). For the 44 contralateral ears, 33 (75.00%) showed normal hearing and 11 (25.00%) presented with sensorineural hearing loss. Auditory brainstem responses were absent or abnormal in all 44 affected ears, while otoacoustic emissions and/or cochlear microphonics were present. Among the 18 patients who underwent magnetic resonance imaging (MRI), 7 (38.89%) presented cochlear nerve deficiency (CND). Nineteen candidate variants were found in 12 patients among the 15 UAN patients who were conducted targeted gene capture and next generation sequencing. Thirty patients were followed up by telephone to investigate their management effect.

CONCLUSIONS

Our study demonstrates comprehensive audiological features of patients with UAN to improve the clinical understanding and diagnosis. Some patients with UAN could show ipsilateral CND and MRI is essential to evaluate if the nerve is deficient. No pathogenic variants that directly related to the pathogenesis of UAN have been found in this study currently.

Estimating the global costs of hearing loss

OBJECTIVE

To estimate the global costs of hearing loss in 2019.

DESIGN

Prevalence-based costing model.

STUDY SAMPLE

Hearing loss data from the 2019 Global Burden of Disease study. Additional non-hearing related health care costs, educational support, exclusion from the labour force in countries with full employment and societal costs posed by lost quality of life were determined. All costs were reported in 2019 purchasing power parity (PPP) adjusted international dollars.

RESULTS

Total global economic costs of hearing loss exceeded $981 billion. 47% of costs were related to quality of life losses, with 32% due to additional costs of poor health in people with hearing loss. 57% of costs were outside of high-income countries. 6.5% of costs were for children aged 0-14. In scenario analysis a 5% reduction in prevalence of hearing loss would reduce global costs by $49 billion.

CONCLUSION

This analysis highlights major economic consequences of not taking action to address hearing loss worldwide. Small reductions in prevalence and/or severity of hearing loss could avert substantial economic costs to society. These cost estimates can also be used to help in modelling the cost effectiveness of interventions to prevent/tackle hearing loss and strengthen the case for investment.