gms | German Medical Science

Permanent hearing impairment in early childhood affects about 1–3 out of 1,000 children and, if left untreated, leads to a delay in language development and in consequence impacts also cognitive development, depending on the degree of hearing impairment. Newborn Hearing Screening (NHS) was introduced nationwide in Germany in 2009 after preparation by the Federal Joint Committee (G-BA), in consequence most early childhood hearing disorders are diagnosed in early infancy [1], [2]. Early involvement in clinical care means that children with hearing disorders and their families have a wide range of treatment options available to them such as monitoring the development with hearing aids or implantable hearing systems [3], [4]. Due to the young age of children and their physiological maturation processes, this represents a particular challenge for pediatric audiological diagnostics. In addition to the measurement possibilities is therefore, trained observation of the very young children during the process of adjustment (hearing aids, cochlear implants) required. Subjective observation criteria such as change in respiratory rate, facial colour, sucking reflex, and movement of extremities (Moro-Reflex) are just some of the possible reactions that may occur during hearing system fitting [5].

Current hearing aid amplification is associated with the expectation to establish a base for the early stages of primary language acquisition. The major goal is to achieve a language development according chronological age of the children. Already during the first year of life, the child articulates first sounds from the third to sixth month of life, so that the auditory feedback loop develops [4]. If the appropriate input from the family is missing, the variance and quantity of phonetic utterances may not develop accordingly. Maternal and paternal interaction including the rate of speech, and contingency between the primary caregiver and the child are the basis for auditory-linguistic learning [6] .Therefore during this process of early hearing aid fitting professionals should take into account the parents' real life world. Early communicative development, sensorimotor function, cognitive and motor skills should be formed within this context [7], [8]. In the case of late provision of hearing aids, language acquisition is impaired to such an extent that this consequently effects adult life.

In Germany, a tight protocol exists for NHS and the follow-up procedures [1], [9]. NHS usually takes place in the maternity hospital. Most clinics use 2-step screening with TEOAE and AABR measurement, less frequently, AABR-only screening is used. In 2-step hearing screening, the initial examination of the new-born measures automated TEOAE. Follow-up stage 1 may take place in practices (ENT, pediatrics, phoniatrics and pedaudiology) with appropriate technical equipment (automated examination and reporting of ABR). A control screening that remains unremarkable requires pediatric audiological confirmation diagnostics (follow-up level 2) in specialized institutions, which should be completed by the 12^th week of life (Children’s Guideline §5, paragraph 1–4 [10], [11]. By the 6^th month of life at the latest, therapy should have been initiated [1], [12].

In addition to the clinical facilities, a network of institutions is available to provide counselling and support to parents after diagnosis and initial fitting of hearing aids. Ideally, there is an interdisciplinary cooperation between the various specialties involved in the care of children with hearing impairment. This includes paediatricians and neuropaediatricians to exclude diseases or syndromes, specialized acousticians and paediatric acousticians who have the experience to fit very young children with appropriate ear moulds and hearing aids, as well as special educators from general and early intervention with a focus on the development of hearing and communication skills. [1]. In Germany, early intervention for children with hearing impairment regulates the federal state due to the federal structures. Generally, early intervention in the hearing and communication disorders is located at the special institutions/schools for children with hearing impairment and is practiced by special educators [13]. For the families there are various possibilities of early support depending on the federal state [14], [15].

The above-mentioned regulations should enable the ideal path for the child's development within the sensitive phases of auditory pathway maturation and language development from the first suspicion through confirmation diagnostics and initiation of therapy including hearing aid amplification and early intervention. The aim is to identify children with profound hearing impairment at an early stage, to create conditions for the acquisition of spoken language and, if necessary, to initiate the step towards further measures, e.g. preoperative diagnostics prior to cochlear implantation.

To achieve the optimal conditions for maturation of the auditory pathway, the quality and quantity of auditory input in the first years of life is of great importance. Even before the introduction of the NHS, hearing aid wearing acceptance in children was studied [16]. In a former study of device, wearing time a questionnaire surveyed by in 116 parent showed that 58% of the children accepted the hearing aids in the range of very well to good, 18.1% accepted them moderately, and 23% of the children accepted the devices very poorly to not at all. In particular, children with unilateral hearing loss, children with conductive hearing loss, children with additional disabilities, and children primarily from non-German homes showed poor acceptance [16].

Prospective investigation in children whose hearing loss ranges from mild to profound have been conducted rarely. In the present study, conducted by the department of phoniatrics and paediatric audiology at the University Hospital of Cologne, data collection took place in the first year of life to investigate in depth the wearing time of hearing aids

In addition to quality management measures, the aim of the study is the long-term observation of the development of children with hearing loss. The examination of hearing and speech development takes place at fixed point in time through guided parent interviews, questionnaires and standardized test procedures.

This article provides the results of the assessment of the first measurement at the first birthday. The central question deals with the development and the hearing aid acceptance of the early fitted children.

Children with hearing loss consult regularly the paediatric audiology department. In the present investigation, the LEAQ questionnaire is administering the hearing and language development. Data logging and duration of wearing time takes place while checking the hearing device, unaided and aided thresholds.

In addition to the LEAQ, the performance of ongoing diagnostics takes place. A professional in special education teacher or speech therapist conducts the assessment according to the principles of multimethod diagnostics. The auditory behaviour and response to instruments and the Ling Sounds was tested [17], [18], [19]. In addition the preverbal and verbal stages, the communicative behaviour and as play is observed [20]. The educator interviews the parent/caretaker about the daily wearing behaviour with hearing aids. The examination takes place in a child-friendly environment.

In this study, the evaluation and investigation of wearing time with hearing aids takes place because subjective assessment of the parents may differ from the values of the data logging from the hearing aid software. However, the assessment of children's wearing time via data logging may also be subject to error and therefore cannot be used exclusively to assess wearing time in children [21]. Asking parents about wearing behaviour as part of the medical history and hearing aid check is part of the concept, so that a plausible assessment of wearing behaviour can be obtained. The classification into good acceptance (8–12 h daily), medium acceptance (4 to 7.9 h daily), and hardly worn to no acceptance (<3.9 h daily) should simplify the analysis. A subgroup (n=122) is formed for more specific evaluation of wearing behaviour. In this subgroup, data logging was available.

Initial experience with data logging showed that the above data in hours reflect the subjective assessment of the parents. Operating errors of the hearing aids, broken devices or infections caused variation in the wearing time. In some cases, data logging differs between the right and left ear; therefore the mean was calculated for the evaluation. In some cases, children were fitted with bone conduction devices and the data logging war available. In single sided or asymmetric hearing losses, the value of the one hearing aid was documented. If no value was available (n=56), this was marked separately. In this case, only the information provided by the parents was used. Throughout an appointment the audiometric examination includes hearing aids control, pedagogical consultation and ongoing diagnosis plus carrying out the LEAQ. Finally, the doctor in paediatric audiology and phoniatrics sums the results up.

The LEAQ surveys the development of hearing and speech at 12 months of life, taking into account the hearing experience in months (12±3 months). The procedure is suitable to observe the course of auditory behaviour in young children with hearing loss and to compare it with the behaviour of hearing children [22]. The LEAQ consists of 35 yes and no questions. The questions describe auditory behaviour in infants between 0 and 24 months of age, listed hierarchically, over the course of development [19]. Parents complete the questionnaire together with the professional, depending on the native language; it is possible to hand out the questionnaire in the corresponding language. Despite the available translations of the LEAQ, it cannot always be assumed that the content was understood in writing, the questions serve as a guided interview in which family interpreters may also be present [19].

The evaluation differentiates between three groups: Children growing up monolingually in German, monolingually with another language, or simultaneously bilingual.

The sample includes a dataset of N=178 children (m=106/w=72). Data collection took place between 2017 and 2022.

Acceptance of hearing aids was recorded via interview and/or data logging in N=178 subjects. For the subgroup (n=122) data logging was documented and for n=56, the children's wearing behaviour was assessed by interviewing the parents.

The severity of the group and the hearing loss are distributed as follows: mild hearing loss (20<34 dB/WHO 1) 11 children (6.2%), moderate hearing loss (35–49 dB/WHO 2) 33 children (18.5%), moderately severe hearing loss (50<64 dB/WHO 3) 18 children (10.1%), severe hearing loss (65<79 dB/WHO 4) 26 children (14.6%), profound hearing loss (80<94 dB/WHO 5) 36 children (20.2%), deafness (95 and greater/WHO 6) 6 children (3.4%), unilaterally deaf (SSD) 28 children (15.7%), and asymmetrical hard loss (AHL) 20 children (11.2%). 15 subjects were fitted with a bone conduction hearing aid unilaterally or bilaterally.

The mean time of hearing aid provision was 4 months and 9 days (1–21; SD 3.2). The mean age at hearing aid assessment for this evaluation was 12 months and 5 days (2–32), and the period of hearing aid provision (the “hearing age”) was a mean of 7 months and 9 days (0–24).

The families spoke either one or more languages, monolingual German 51.7% (n=92), monolingual a language other than German 30.9% (n=55), and multiple languages within a family 17.4% (n=31) (s. Table 1 [Tab. 1]). Aetiology of hearing impairment shows Table 2 [Tab. 2].

Isolated hearing loss was present in 77.5% (n=138), acquired hearing loss for example auditory synaptopathy/neuropathy (AS/AN) or cytomegalo virus in 5.6% (n=10), conductive hearing loss in 8.4% (n=15), and syndromal hearing loss in 2.3% (n=4).

The data were analysed using Excel and SPSS version 29. Inferential statistics methods were used to calculate the differences between the medians of the dependent and independent variables. In this case, the Kruskal-Wallis test is applied. For calculation, the effect size the correlation coefficient r was used. Demographic data were analysed with the means of descriptive statistics. The comparison of means between the variables “data logging” and “languages” was calculated with a one-factor analysis of variance and adjusted with the Bonferroni post-hoc formula. The significance level is defined at p≤0.05 (95% confidence interval).

This evaluation is part of an investigation approved by the Ethics Committee of the University of Cologne (Faculty of Medicine) (Document: 18–134). There are no conflicts of interest.

1.

The LEAQ questionnaire score as a feature of hearing and language development correlates with the severity of hearing impairment.

2.

Hearing aid acceptance correlates with LEAQ scores.

3.

The wearing time of the hearing aids, differs between children raised monolingual in German, children raised monolingual but in other languages, and the group of families that maintain simultaneous bilingual language acquisition.

4.

The cause of hearing loss correlates with hearing aid acceptance.

Descriptive analysis of wearing time (data logging and interview with parents) with hearing aids yields the following values: 8 to 12 h, (good) acceptance in 44.9% (n=80), 4 to 7.9 h, (medium) acceptance in 25.3% (n=45), less than 3.9 h, (poor) acceptance in 29.8% (n=53) (s. Figure 1 [Fig. 1]).

In the LEAQ, a mean of 15 questions (0–35; SD 9.2) are answered positive in the sample. With a mean age of 12 months and 5 days (2–32; SD 4.9), this value corresponds to a developmental age of 6–10 months. The mean age of hearing development is 7 months and 8 days (0–24; SD 5.4). The discrepancy with chronological age of 12 months and 5 day spans between 2 and 4 months and 5 days for the sample. 44% (n=79) deviated from the mean 15; 0 points at 12 months 5 days. This affected 18% of children with mild hearing loss, 9.1% with moderate hearing loss, 50% with moderately severe hearing loss, 53,8% with severe hearing loss, 86% with profound hearing loss, 83.3% with deafness, 42.8% with unilateral deafness, and 15% with asymmetric hearing loss (Table 1 [Tab. 1]).

In Figure 1 [Fig. 1], the scatter plot represents the distribution of scores in the LEAQ as a function of age in months and severity of hearing loss. The variables “degree of hearing loss” and “total scores in the LEAQ” show a positive correlation (Figure 2 [Fig. 2]). In the pairwise comparison of medians, there is a significant difference of p≤0.001 between the score in the questionnaire score in the profound hearing loss (65 dB and deafness >95 dB) and WHO grades 1–3 groups. In addition, there is a significant difference between the groups’ asymmetric hearing loss (AHL) or unilateral deafness (SSD) and the group of profound hearing loss. Significance values are adjusted with the Bonferroni correction. For the groups that differ significantly, a correlation coefficient of r=0.1 is calculated. In summary, the pairwise comparison by the Kruskal-Wallis test shows that the degree of hearing loss influences the outcome in the LEAQ. Therefore, the procedure is a good instrument for follow-up diagnosis during clinical follow-up. As expected, the group of children with mild hearing loss differs in terms of hearing and language development from the group of children with severely, profound hearing loss or deafness. However, based on the scatter plot, there are indications that n=79 (44.4%) of the participants are below the minimum level. This demonstrates that language acquisition is at risk and hearing aid checks are particularly important for this group so that addressing developmental delays early is possible. Table 1 [Tab. 1] shows that the risk of language delay concerns all degrees of hearing losses, especially the children with profound hearing loss to deafness, but also the subjects with unilateral deafness (12/28 children) and moderate hearing loss.

The correlation between the acceptance of the hearing aids and the results in the questionnaire score does not show a significant correlation between acceptance and wearing time of the hearing aids and the LEAQ at 12 months and 5 days of age (p<0.353). This confirms the second hypothesis.

Since the language of origin and the reality of life have a decisive influence on the (overall) development of the child [24], the variable “language of origin” is analysed separately in a subgroup. The median test compared (see Figure 3 [Fig. 3]) the variables “language” (language spoken in the family) and “data logging” (n=122). There is a significant difference (p≤0.001). Between the group “German” and “simultaneous multilingualism” in the family the significance is smaller (p≤0.038).

The correlation between “aetiology of hearing loss” and “data logging” is statistically significant. These groups differ significantly (p≤0.028).

This study group shows that at the age of one year, the acceptance and wearing time of the hearing aids is between 8 to 12 h for 44.9% of the children, that indicates a good acceptance. 25.3% wear the hearing aids between 4 and 7.9 h. Since children’s bedtimes hours can be even longer in the first year of life, it can be assumed that the wearing time increases during the second year of life [16]. Data from data logging are beneficial for consulting parents. However, it does not seem appropriate to use data logging as the only basis for evaluating wearing acceptance, since the child's illness, technical faults in the hearing instrument, or the handling of the hearing instrument can influence the period of measurement [21]. At an average of 4 months and 9 days of life, the initiation and amplification of hearing aids reaches the standards of six months according to the German Guidelines [11].

The significant difference (Figure 3 [Fig. 3]) between “monolingual German” and “monolingual other language” or “simultaneous bilingual” groups implies that there is still a need for counselling and/or education among families who predominantly speak another language [16], as hearing aid wearing, maternal education, and nonverbal intelligence are predictors of further development [25]. These variables were not included in this stage of the evaluation and this implies its limitations. The reasons for not putting on the hearing aids was not systematically recorded. Though parents reported that the child always took out the hearing aids, that the child was still very small, or that the hearing behaviour did not differ with and without hearing aids. Despite the presence of interpreters during the hearing aid fitting process, the importance of hearing aid amplification and wearing was not clear to some of the parents. Barriers such as the acceptance of the diagnosis (coping) in the process of amplification or the function of hearing aids and their impact on early language development have not been resolved at the time of the study.

Children with an additional medical condition, syndrome, or other acquired cause of hearing loss also show lower acceptance, in contrast to the group of children without an additional disability. Although the timing of fitting is significantly earlier, problems with wearing acceptance persist in children with additional problems [16].

The implementation of the LEAQ for families from other countries of origin is possible in their native language since the test is available in many languages. It is a good tool on an easy level. It guides the child’s hearing development hierarchically and educates at the same time [19]. The LEAQ allows a reliable determination of the stages of hearing development.

A lower questionnaire score was expected for children with profound hearing loss (Figure 1 [Fig. 1]) However, the outliers suggest that early hearing aid fitting at least stimulates auditory maturation [25]. Various factors are important for successful progression. These include time of amplification, degree of hearing loss, hearing aid setting, and duration of wearing time per day [8], [25]. Data from brainstem audiometry indicate that to some extent, especially in the first year of life, hearing aid fitting substitutes the maturation processes in children with mild to moderate hearing loss [26]. Some of the children with profound hearing loss or deafness are candidates for a cochlear implantation. The early provision of hearing aids before CI fitting simplifies the introduction of hearing with a CI system for these children and shortens the phase without hearing device.

Children with profound hearing losses between 65 and 80 dB have improved their speech and language development through the possibility of improved hearing of a cochlear implant [27]. In this context, the improvement of psycho-social development, comprehension in noise and localization of speech are expected and in consequence affect the quality of life [28]. Early diagnosis is therefore essential for the prospective development [27].

In the group of children with mild to moderate hearing loss, many do not achieve an age-appropriate hearing and speech development by the first year of life (Table 1 [Tab. 1]). Thus, further monitoring of development in the second year of life seems appropriate. Even children with unilateral deafness still show not age appropriate language development, so that it is necessary to monitor further language acquisition and, if necessary, the start appropriate speech therapy.

Which is essential for the formation of the phonetic-phonological loop, the segmentation of language and the growth of the first vocabulary [24]. Poor auditory comprehension shows long-term consequences for the auditory memory, the acquisition of vocabulary, the evolution of grammar, and psycho-social development [6], [24], [29], [30].

Regular check-ups in a clinic for phoniatrics and pediatric audiology are necessary to achieve the milestones of primary language acquisition. Part of the progress includes diagnostics, therapy and if necessary further early intervention programs. This may eliminate potential barriers of accepting hearing aids and helps parents throughout the coping progress.

Diagnosis and consultation regarding the function of the technique remain important aspects of clinical treatment. The quality of early interaction between parent and child, eye contact, preverbal development, verbal and nonverbal behaviour, gestures and facial expressions as well triangular attention should also be included early in clinical treatment [6], [31]. However, despite comprehensive diagnosis and counselling, hurdles remain in communicating because of the diagnosis, especially to families with a language other than German.

In order to achieve the longest possible wearing time of the hearing aids or a high level of hearing aid acceptance in the first year of life, the following points are important:

• The amplification process and consulting parents are particularly important areas.
• The ear moulds must be comfortable and the setting of the hearing aids must be adapted to the hearing threshold so that wearing acceptance is increased and hearing responses become clear.
• In the phase of initial diagnosis, parents need an easy access to support from early intervention professionals.
• Early intervention of specialists in hearing and language development should take place on a regular basis.
• With mild hearing loss, children respond to auditory stimuli. Nevertheless, parents need to understand the long-term benefits of hearing aids for speech development.
• Families from non-German speaking backgrounds may need cultural mediators to communicate the diagnosis and understand the importance of therapy.

The LEAQ is a procedure that is good at recording the course of hearing development in the first year of life. Through the concrete examples, parents can assess their child’s hearing behaviour themselves. The questionnaire additionally reflects the child's development with hearing aids.

Early childhood diagnosis, intervention, and ongoing support for children with congenital and acquired hearing impairments requires a multiprofessional setting.

The authors declare that they have no competing interests.