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Objective: To assess the efficacy of valganciclovir in infants with hearing loss and clinically inapparent congenital cytomegalovirus infection (cCMV), as there is no consensus on treatment of this group., Study Design: A nationwide, nonrandomized controlled trial, comparing 6 weeks of oral valganciclovir to no treatment in infants with cCMV, recruited after newborn hearing screening resulted in referral to an audiologist. The choice whether to treat was left to parents of subjects. Eligible subjects were full term infants aged <13 weeks with sensorineural hearing loss and diagnosed with cCMV through dried blood spot testing. The primary outcome, measured by linear and ordinal logistic regression, was change in best-ear hearing from baseline to follow-up at 18-22 months of age., Results: Thirty-seven participants were included in the final analysis, of whom 25 were in the treatment group and 12 in the control group. The majority of subjects in both groups had neuroimaging abnormalities, which were mostly mild. Hearing deterioration was more likely in the control group compared with the treatment group (common OR 0.10, 95% CI 0.02-0.45, P = .003). Mean best-ear hearing deteriorated by 13.7 dB in the control group, compared with improvement of 3.3 dB in the treatment group (difference 17 dB, 95% CI 2.6 - 31.4, P = .02)., Conclusions: We investigated treatment in children with hearing loss and clinically inapparent cCMV. Although our study was nonrandomized, it is the first prospective and controlled trial in this population. Valganciclovir-treated children with hearing loss and inapparent cCMV had less hearing deterioration at 18 through 22 months of age than control subjects., Eudract Registry Number: 2013-003068-30., Competing Interests: Declaration of Competing Interest A.C.T.M.V. reports financial support was provided by NutsOhra Fund (grant number 0901-054). A.M.O.-M. reports a relationship with National advisory board on newborn hearing screening that includes board membership. The other authors declare no conflicts of interest., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: To evaluate clinical, audiological and neuroimaging findings in a cohort of infants diagnosed with congenital cytomegalovirus (cCMV) infection after failure at newborn hearing screening., Methods: A prospective observational study in the Netherlands, using the existing newborn hearing screening infrastructure for well babies. Between July 2012 and November 2016, cytomegalovirus (CMV) PCR testing of neonatally obtained dried blood spots (DBS) was offered to all infants who failed newborn hearing screening. Clinical, neuroimaging and audiological data were collected., Results: DBS of 1374 infants were successfully tested and 59 were positive for CMV (4.3%). Data of 54 infants were retrieved. Three were small for gestational age and six had microcephaly. Forty-eight (89%) had sensorineural hearing loss (SNHL), of whom half had unilateral SNHL. In both unilaterally and bilaterally affected children, the majority of the impaired ears had severe or profound hearing loss. Neuroimaging abnormalities were found in 40 of 48 (83%) children who had evaluable cranial ultrasound and/or cerebral MRI. The abnormalities were mild in 34, moderate in 3 and severe in 3 infants. The degree of SNHL and the severity of neuroimaging abnormalities were found to be correlated (p=0.002)., Conclusions: The yield of targeted cCMV screening following newborn hearing screening failure was eight times higher than the estimated national birth prevalence of cCMV. The majority of this cohort of infants with clinically unsuspected cCMV disease had confirmed SNHL, neuroimaging abnormalities and lower than average birth weights and head circumferences. Newborns who fail newborn hearing screening should be tested for CMV to ensure appropriate clinical, neurodevelopmental and audiological follow-up., Competing Interests: Competing interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The authors declare the following non-financial interests/personal relationships which may be considered as potential competing interests: AMO-M is a member of the national advisory board on newborn hearing screening, which is an unpaid function., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Children with hearing loss (HL) are at risk for a lower educational achievement. This longitudinal study compared the school career of a nationwide Dutch cohort with and without HL based on descriptive data of the governmental authority Statistics Netherlands. From 2008 to 2018, 3,367,129 children, of whom 1,193 used cochlear implants (CIs) and 8,874 used hearing aids (HAs), were attending primary and/or secondary education. Sixty-one percent of children with HL attended mainstream and 31% special primary education. Compared to mainstreamed pupils without HL, mainstreamed pupils with HL achieved lower levels for language and mathematics in primary education but eventually attended comparable types of secondary education. Children with HL attending special primary education attained lower types of secondary education compared to mainstreamed peers with and without HL. These findings suggest that future educational (and as a result professional) attainment of a child with HL depends on the type of primary educational setting., (© The Author(s) 2021. Published by Oxford University Press.)

Objectives: To compare the quality of life (QoL) of children with hearing loss (HL) and children with normal hearing (NH) and to examine how the QoL of children with HL changes over time, considering language skills, type of hearing device, degree of HL, and type of education., Methods and Materials: This longitudinal study included 62 children with HL and their parents. Developmental outcome data were collected at two time points, when the mean ages of the children were 4 and 11 years. The Pediatric Quality of Life (PedsQL™) questionnaire, which includes assessments of Physical, Emotional, Social, and School functioning, was completed by parents at both time points and by the children with HL at the second time point. Receptive and expressive language skills at 4 years were assessed by the Reynell Developmental Language Scale. Results were compared with a Dutch normative sample., Results: The QoL of children with HL was similar to that of children with NH at both time points on two of the four QoL scales, Emotional and Physical functioning. On the other two scales, Social and School functioning, children with HL who attended special education and children who switched to mainstream education showed lower scores than children with HL who were consistently in mainstream education and lower scores than children with NH. The School QoL of children with HL decreased over time, as did the School QoL of children with NH. Social QoL of children with cochlear implants decreased over time, but this was not the case in children with hearing aids. Language skills and the degree of HL did not clinically improve the QoL over time of preschool children with HL., Conclusions: The QoL of children with HL in mainstream education and the Physical and Emotional QoL of all children with HL were satisfactory. It is essential to develop specific guidance regarding school activities for children with HL in special education and for children with HL who switch to mainstream education in order to increase their social QoL., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Purpose The aim of the study was to evaluate the application of a modified version of the Amsterdam Inventory for Auditory Disabilities and Handicap to inventory self-reported hearing difficulties pre and post hearing aid fitting in 6 dimensions: detection, speech in silence, speech in noise, localization, discrimination, and noise tolerance. Method Questionnaires pre and post hearing aid fitting were collected during regular practice of hearing aid provision. Data of 740 subjects are presented; 337 already used hearing aids, and 403 were new users. Results Group-averaged scores improved due to hearing aid fitting for all 6 dimensions. Based on a criterion previously defined for the Amsterdam Inventory for Auditory Disabilities and Handicap questionnaire, 66% of subjects had a significant individual improvement in sum score. Experienced users showed lower improvement in scores, whereas their aided prescores were, on average, not better than the (unaided) score of 1st users. Conclusions The questionnaire can be applied as a structured approach to inventory hearing problems in 6 dimensions prior to hearing aid fitting and to systematically evaluate the effects of hearing aid fitting after a trial period. The data presented here can serve as normative data for comparison of individual subjects in clinical practice.

Objective: Cochlear implants (CIs) have dramatically improved the lives of children who are deaf or hard of hearing; however, little is known about its implications for preventing the development of psychiatric symptoms in this at-risk population. This is the first longitudinal study to examine the early manifestation of emotional and behavioral disorders and associated risk and protective factors in early identified preschoolers with CIs compared with hearing peers., Design: Participants were 74 children with CIs and 190 hearing controls between ages 1 and 5 years (mean age, 3.8 years). Hearing loss was detected using the Newborn Hearing Screening in The Netherlands and Flanders. Parents completed the Early Childhood Inventory-4, a well-validated measure, to evaluate the symptoms of DSM-IV-defined psychiatric disorders, during three consecutive years. Language scores were derived from each child's medical notes., Results: Children with CIs and hearing controls evidenced comparable levels of disruptive behavior and anxiety/depression (which increased with age in both groups). Greater proficiency in language skills was associated with lower levels of psychopathology. Early CI and longer duration of CI use resulted in better language development. In turn, higher early language skills served as a protective factor against the development of disruptive behavior symptoms., Conclusions: This longitudinal study uniquely shows that improvement in language skills mitigates the development of early signs of psychopathology. Early identification of hearing loss and CIs help children improve their language skills.

There is lack of a systematic approach concerning how to select an adequate hearing aid and how to evaluate its efficacy with respect to the personal needs of rehabilitation. The goal of this study was to examine the applicability and added value of two widely used self-reporting questionnaires in relation to the evaluation of hearing aid fitting. We analyzed responses, pre- and postfitting, from 1,319 subjects who completed the Client Oriented Scale of Improvement (COSI) and a slightly adapted version of the Amsterdam Inventory for Auditory Disability and Handicap (in Dutch: AVAB). Most COSI responses were at or near the maximum possible score. Results show a close relation between COSI's degree of change and final ability (Spearman's rho = 0.71). Both AVAB and COSI showed a significant effect of hearing aid experience, but-in contrast to AVAB-COSI did not show a significant effect of the degree of hearing loss. In addition, a Friedman test showed significant differences between six dimensions of auditory functioning for both AVAB and COSI, although post hoc analysis revealed that for COSI, the dimension speech in quiet explained most variation between dimensions. In conclusion, the effects of hearing loss were more salient in AVAB, while both AVAB and COSI showed differences regarding hearing aid experience. Combining the advantages of both methods results in a detailed evaluation of hearing aid rehabilitation. Our results therefore suggest that both methods should be used in a complementary manner, rather than separately.

Objectives: The first aim of this study was to examine various aspects of Theory of Mind (ToM) development in young children with moderate hearing loss (MHL) compared with hearing peers. The second aim was to examine the relation between language abilities and ToM in both groups. The third aim was to compare the sequence of ToM development between children with MHL and hearing peers., Design: Forty-four children between 3 and 5 years old with MHL (35 to 70 dB HL) who preferred to use spoken language were identified from a nationwide study on hearing loss in young children. These children were compared with 101 hearing peers. Children were observed during several tasks to measure intention understanding, the acknowledgement of the other's desires, and belief understanding. Parents completed two scales of the child development inventory to assess expressive language and language comprehension in all participants. Objective language test scores were available from the medical files of children with MHL., Results: Children with MHL showed comparable levels of intention understanding but lower levels of both desire and belief understanding than hearing peers. Parents reported lower language abilities in children with MHL compared with hearing peers. Yet, the language levels of children with MHL were within the average range compared with test normative samples. A stronger relation between language and ToM was found in the hearing children than in children with MHL. The expected developmental sequence of ToM skills was divergent in approximately one-fourth of children with MHL, when compared with hearing children., Conclusion: Children with MHL have more difficulty in their ToM reasoning than hearing peers, despite the fact that their language abilities lie within the average range compared with test normative samples.

Objective: Clinical studies are often facing missing data. Data can be missing for various reasons, for example, patients moved, certain measurements are only administered in high-risk groups, and patients are unable to attend clinic because of their health status. There are various ways to handle these missing data (e.g., complete cases analyses, mean substitution). Each of these techniques potentially influences both the analyses and the results of a study. The first aim of this structured review was to analyze how often researchers in the field of otorhinolaryngology/head & neck surgery report missing data. The second aim was to systematically describe how researchers handle missing data in their analyses. The third aim was to provide a solution on how to deal with missing data by means of the multiple imputation technique. With this review, we aim to contribute to a higher quality of reporting in otorhinolaryngology research., Design: Clinical studies among the 398 most recently published research articles in three major journals in the field of otorhinolaryngology/head & neck surgery were analyzed based on how researchers reported and handled missing data., Results: Of the 316 clinical studies, 85 studies reported some form of missing data. Of those 85, only a small number (12 studies, 3.8%) actively handled the missingness in their data. The majority of researchers exclude incomplete cases, which results in biased outcomes and a drop in statistical power., Conclusions: Within otorhinolaryngology research, missing data are largely ignored and underreported, and consequently, handled inadequately. This has major impact on the results and conclusions drawn from this research. Based on the outcomes of this review, we provide solutions on how to deal with missing data. To illustrate, we clarify the use of multiple imputation techniques, which recently became widely available in standard statistical programs.

Objective: Permanent childhood hearing impairment often results in speech and language problems that are already apparent in early childhood. Past studies show a clear link between language skills and the child's social-emotional functioning. The aim of this study was to examine the level of language and communication skills after the introduction of early identification services and their relation with social functioning and behavioral problems in deaf and hard of hearing children., Study Design: Nationwide cross-sectional observation of a cohort of 85 early identified deaf and hard of hearing preschool children (aged 30-66 months)., Methods: Parents reported on their child's communicative abilities (MacArthur-Bates Communicative Development Inventory III), social functioning and appearance of behavioral problems (Strengths and Difficulties Questionnaire). Receptive and expressive language skills were measured using the Reynell Developmental Language Scale and the Schlichting Expressive Language Test, derived from the child's medical records., Results: Language and communicative abilities of early identified deaf and hard of hearing children are not on a par with hearing peers. Compared to normative scores from hearing children, parents of deaf and hard of hearing children reported lower social functioning and more behavioral problems. Higher communicative abilities were related to better social functioning and less behavioral problems. No relation was found between the degree of hearing loss, age at amplification, uni- or bilateral amplification, mode of communication and social functioning and behavioral problems., Conclusion: These results suggest that improving the communicative abilities of deaf and hard of hearing children could improve their social-emotional functioning., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Objectives: Children with hearing loss are at risk of developing psychopathology, which has detrimental consequences for academic and psychosocial functioning later in life. Yet, the causes of the extensive variability in outcomes are not fully understood. Therefore, the authors wanted to objectify symptoms of psychopathology in children with cochlear implants or hearing aids, and in normally hearing peers, and to identify various risk and protective factors., Design: The large sample (mean age = 11.8 years) included three subgroups with comparable age, gender, socioeconomic status, and nonverbal intelligence: 57 with cochlear implants, 75 with conventional hearing aids, and 129 children who were normally hearing. Psychopathology was assessed by means of self- and parent-report measures., Results: Children with cochlear implants showed similar levels of symptoms of psychopathology when compared with their normally hearing peers, but children with hearing aids had significantly higher levels of psychopathological symptoms, while their hearing losses were approximately 43 dB lower than those of children with implants. Type of device was related with internalizing symptoms but not with externalizing symptoms. Furthermore, lower age and sufficient language and communication skills predicted less psychopathological symptoms., Conclusions: Children who are deaf or profoundly hearing impaired and have cochlear implants have lower levels of psychopathological symptoms than children with moderate or severe hearing loss who have hearing aids. Most likely, it is not the type of hearing device but rather the intensity of the rehabilitation program that can account for this difference. This outcome has major consequences for the next generation of children with hearing loss because children with profound hearing impairment still have the potential to have levels of psychopathology that are comparable to children who are normally hearing.

Objective: The purpose of this study was to examine the level of empathy in deaf and hard of hearing (pre)adolescents compared to normal hearing controls and to define the influence of language and various hearing loss characteristics on the development of empathy., Methods: The study group (mean age 11.9 years) consisted of 122 deaf and hard of hearing children (52 children with cochlear implants and 70 children with conventional hearing aids) and 162 normal hearing children. The two groups were compared using self-reports, a parent-report and observation tasks to rate the children's level of empathy, their attendance to others' emotions, emotion recognition, and supportive behavior., Results: Deaf and hard of hearing children reported lower levels of cognitive empathy and prosocial motivation than normal hearing children, regardless of their type of hearing device. The level of emotion recognition was equal in both groups. During observations, deaf and hard of hearing children showed more attention to the emotion evoking events but less supportive behavior compared to their normal hearing peers. Deaf and hard of hearing children attending mainstream education or using oral language show higher levels of cognitive empathy and prosocial motivation than deaf and hard of hearing children who use sign (supported) language or attend special education. However, they are still outperformed by normal hearing children., Conclusions: Deaf and hard of hearing children, especially those in special education, show lower levels of empathy than normal hearing children, which can have consequences for initiating and maintaining relationships.

Objective: Sufficient self-esteem is extremely important for psychosocial functioning. It is hypothesized that hearing-impaired (HI) children have lower levels of self-esteem, because, among other things, they frequently experience lower language and communication skills. Therefore, the aim of this study was to compare HI children's self-esteem across different domains with those of normal hearing (NH) children and to investigate the influence of communication, type of education, and audiological characteristics., Methods: This large (N = 252) retrospective, multicenter study consisted of two age- and gender-matched groups: 123 HI children and 129 NH controls (mean age  = 11.8 years). Self-reports were used to measure self-esteem across four domains: perceived social acceptance by peers, perceived parental attention, perceived physical appearance, and global self-esteem., Results: HI children experienced lower levels of self-esteem regarding peers and parents than NH controls. Particularly HI children who attended special education for the deaf were at risk, even after correcting for their language development and intelligence. Yet, levels of global self-esteem and self-esteem involving physical appearance in HI children equalled those of NH controls. Furthermore, younger age at implantation and longer duration of having cochlear implants (CIs) were related to higher levels of self-esteem., Conclusion: HI children experience lower levels of self-esteem in the social domains. Yet, due to the heterogeneity of the HI population, there is high variability in levels of self-esteem., Discussion: Clinicians must always be aware of the risk and protective factors related to self-esteem in order to help individual patients reach their full potential.

The purpose of this study was to examine several behavioral problems in school-aged hearing-impaired children with hearing aids or cochlear implants, compared to normally hearing children. Additionally, we wanted to investigate which sociodemographic, linguistic, and medical factors contributed to the level of behavioral problems, to pinpoint where targeted interventions can take place. This large, retrospective study included a sample of 261 school-aged children (mean age = 11.8 years, SD = 1.6), that consisted of three age- and gender-matched subgroups: 75 with hearing aids, 57 with cochlear implants, and 129 normally hearing controls. Self- and parent-reports concerning reactive and proactive aggression, delinquency, and symptoms of psychopathy, attention deficit hyperactivity disorder, oppositional defiant disorder, and conduct disorder were used. In addition, several language and intelligence tests were administered. Hearing-impaired children showed significantly more proactive aggression, symptoms of psychopathy, attention deficit hyperactivity disorder, oppositional defiant disorder, and conduct disorder than their normally hearing peers. More behavioral problems were associated with special schools for the deaf, sign (-supported) language, hearing aids (in contrast to cochlear implants), higher age, male gender, lower socioeconomic status, lower intelligence, and delayed language development. Hearing-impaired children face multiple problems regarding their behavior. The outcomes implicate that professionals should be aware of the higher risk of developing behavioral problems, in order to screen, detect, and treat in time. Furthermore, the associated risk and protective factors emphasize that clinicians must always consider the heterogeneity of the group of hearing-impaired children, in order to help and support the individual patient.

Importance: Pediatric hearing impairment is a chronic handicap that can potentially lead to the development of psychopathology. Yet, for hearing-impaired children and adolescents, the exact occurrence of various forms of psychopathology and its causes are unclear, while this knowledge is essential to enable targeted screenings and interventions., Objective: To investigate the level of psychopathological symptoms in hearing-impaired children and adolescents as compared with normally hearing peers. Second, the influence of type of hearing device and possible risk and protective factors on psychopathology were examined., Evidence Review: A systematic literature search was performed covering relevant databases, including PubMed, Embase, and Web of Science. Two independent researchers identified the relevant articles. The final search was performed on May 2, 2013, and resulted in a total of 35 articles., Findings: Literature consistently demonstrated that hearing-impaired children and adolescents were more prone to developing depression, aggression, oppositional defiant disorder, conduct disorder, and psychopathy than their normally hearing peers. Levels of anxiety, somatization, and delinquency were elevated in some, but not all, hearing-impaired participants, for reasons related to sex, age, and type of school. Divergent results were obtained for the level of attention-deficit/hyperactivity disorder and the influence of type of hearing device on psychopathology. Possible risk and protective factors were identified, including age at detection and intervention of hearing loss, additional disabilities, communication skills, intelligence, type of school, and number of siblings., Conclusions and Relevance: Literature on psychopathology in hearing-impaired children and adolescents is scarce and sometimes inconsistent. To define a more precise occurrence of psychopathology, more studies are needed. These studies should have a longitudinal design to draw firmer conclusions on causality. Hopefully, this will lead to more knowledge in the future to help and support each hearing-impaired individual.

Objectives/hypothesis: The objectives of this study were to examine the levels of anxiety in hearing-impaired children with hearing aids or cochlear implants compared to normally hearing children, and to identify individual variables that were associated with differences in the level of anxiety., Study Design: Large retrospective cohort study., Methods: Self-reports and parent-reports concerning general anxiety, social anxiety, and generalized anxiety disorder were used. The study group (mean age, 11.8 years) consisted of three age-matched subgroups: 32 children with cochlear implants, 51 children with conventional hearing aids, and 127 children without hearing loss., Results: Levels of anxiety in children with cochlear implants and normally hearing children were similar. Early implantation was associated with lower levels of general and social anxiety. Remarkably, children with conventional hearing aids had higher levels of social anxiety, and their parents also reported more generalized anxiety disorder., Conclusions: The outcomes demonstrate that in their level of anxiety, children with cochlear implants might be more comparable to normally hearing children than to children with hearing aids. This positive finding can be the consequence of audiological factors or other aspects of the cochlear implant rehabilitation program., (Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.)

Objective: The purpose of this study was to examine the levels of depressive symptoms and the unique contribution of two aspects of emotion regulation (coping and mood states) to the development of depression in hearing-impaired children and a control group., Methods: In order to compare the groups, self-report questionnaires concerning symptoms of depression, coping strategies, and mood states were used. The study group consisted of 27 children with cochlear implants, 56 children with conventional hearing aids, and 117 normally hearing children., Results: Hearing-impaired children reliably reported more symptoms of depression than their normally hearing peers. Degree of hearing loss, socioeconomic status, gender, and age were unrelated to the level of depressive symptoms. But attending mainstream schools or using exclusively speech for communication were related to fewer depressive symptoms. The associations with depressive symptoms differed between the groups. For hearing-impaired children, the cognitive aspects (coping) and the affective aspects (mood states) of emotional functioning contributed separately to the prediction of depressive symptoms. For normally hearing children an integration of cognitive and affective aspects was detected: adequate coping skills prevented the development of negative mood states and in turn depressive symptoms., Conclusions: Hearing-impaired children reported more depressive symptoms than normally hearing children. Prevention and treatment of depression in hearing-impaired children could focus on the use of coping strategies adequately, because these strategies have a direct relation with the level of depression., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

This study introduced a dual-masker forward masking technique and evaluated whether this objective method could measure electrode independency in a cochlear implant; more particularly, whether the optimal locations and number of active electrodes could be determined. This method further enabled the investigation of the efficacy of current steering, because the proposed recording method could also be described as applying a sequentially current steered masker. The paradigm requires 5 frames involving 2 maskers and 1 probe and is referred to as the Apple Core method (MP5-AC). For each recording, both the masker and probe amplitude were varied independently, producing 3-D eCAP plots that showed the eCAP amplitude for independent variations of masker and probe amplitudes. A simple quantitative model was developed to aid interpretation of the results. Theory and model were clinically tested in 14 patients. On the basis of the model, the multi-variate, color-coded plots could be subdivided into seven distinct regions, each depicting a unique relationship between the probe and the maskers. The model's predictions supported interpretation of the results, and indicated independence for the probe electrode contacts only at lower current levels and/or at greater inter-electrode separations. The clinical results revealed a lack of selectivity in the electrode array for stimulus levels larger than 600 microA. This suggests that sequential current steering is only capable of producing a single excitation area at higher current levels, or smaller electrode distances, without additional loudness correction being applied. Thus, the MP5-AC paradigm provided insight concerning the independence of electrodes and the efficacy of current steering in clinical patients. However, its current clinical applicability is limited because measurements were adequate only in anesthetized patients.

A directional hearing aid might be beneficial in reducing background noise in relation to the desired speech signal. Conventional hearing aids with a directional cardioid microphone are insufficient because of the low directivity of cardioids. Research was done to develop microphone(s) with strong directional characteristics using array techniques. Particular emphasis was given to optimization and stability. Free-field simulations of several robust models show that a directivity index of 9 dB can be obtained at the higher frequencies. Simulations were verified with a laboratory model. The results of the measurements show a good agreement with the simulations. Based on simulations and measurements, two portable models were developed and tested with a KEMAR manikin. The KEMAR measurements show that the two models give an improvement of the signal-to-noise ratio of approximately 7.5 dB in a diffuse sound field. It may be concluded that the developed microphones have the capability to reach a significant improvement of speech intelligibility in noise under practical circumstances.

Hearing-impaired listeners often have great difficulty understanding speech in surroundings with background noise or reverberation. Based on array techniques, two microphone prototypes (broadside and endfire) have been developed with strongly directional characteristics [Soede et al., "Development of a new directional hearing instrument based on array technology," J. Acoust. Soc. Am. 94, 785-798 (1993)]. Physical measurements show that the arrays attenuate reverberant sound by 6 dB (free-field) and can improve the signal-to-noise ratio by 7 dB in a diffuse noise field (measured with a KEMAR manikin). For the clinical assessment of these microphones an experimental setup was made in a sound-insulated listening room with one loudspeaker in front of the listener simulating the partner in a discussion and eight loudspeakers placed on the edges of a cube producing a diffuse background noise. The hearing-impaired subject wearing his own (familiar) hearing aid is placed in the center of the cube. The speech-reception threshold in noise for simple Dutch sentences was determined with a normal single omnidirectional microphone and with one of the microphone arrays. The results of monaural listening tests with hearing impaired subjects show that in comparison with an omnidirectional hearing-aid microphone the broadside and endfire microphone array gives a mean improvement of the speech reception threshold in noise of 7.0 dB (26 subjects) and 6.8 dB (27 subjects), respectively. Binaural listening with two endfire microphone arrays gives a binaural improvement which is comparable to the binaural improvement obtained by listening with two normal ears or two conventional hearing aids.

Hearing-impaired listeners often have great difficulty understanding speech in situations with background noise (e.g., meetings, parties). Conventional hearing aids offer insufficient directivity to significantly reduce background noise relative to the desired speech signal. Based on array techniques, microphone prototypes have been developed with strongly directional characteristics to be incorporated into the frame and the "temples" of a pair of eyeglasses. Particular emphasis was on optimization and electronic stability. Computer simulations show that a directivity index of more than 10 dB can be obtained at the higher frequencies. Simulations were verified with free-field measurements. To investigate the influence of the human head on directivity, two portable models were also tested with a KEMAR manikin. The measurements show that the two models give an improvement of the signal-to-noise ratio of approximately 7 dB in a diffuse background noise field compared with an omnidirectional microphone. For the clinical assessment of these microphone arrays in the diffuse noise field (simulating a cocktail party situation), the speech-reception threshold in noise for simple Dutch sentences was determined with a normal single omnidirectional microphone and with one of the microphone arrays. The results of monaural listening tests of 30 subjects with normal hearing and 45 subjects with hearing impairment show that the microphone arrays give a mean improvement of the speech reception threshold in noise of about 7 dB compared with an omnidirectional microphone.

The hearing impaired often have great difficulty understanding speech in surroundings with background noise or reverberation. A directional hearing aid might be beneficial in reducing background noise in relation to the desired speech signal. To this end microphone systems were developed with strongly directional characteristics, using array techniques. Considerable attention was paid to optimization and stability. Free-field simulations of several robust models showed that a directivity index of 9 dB can be obtained. Simulations were verified with a laboratory model. Based on simulations and measurements, two portable prototypes were developed and tested using a KEMAR-manikin. The KEMAR-measurements showed that the two prototypes gave an improvement of the signal to noise ratio of 7 dB in a fully diffuse sound field. The benefit of these microphone arrays for the hearing impaired was tested in a sound insulated room. One loudspeaker was placed in front of the listener simulating the partner in a discussion, and a diffuse background noise was produced by eight loudspeakers placed on the corners of a cube. The hearing impaired subject was seated in the centre of the cube. The speech-reception threshold in noise for simple Dutch sentences was determined with a normal single omni-directional microphone and with one of the prototypes. The results of the listening tests with 45 hearing impaired subjects showed an average improvement of the S/N-ratio of 7.0 dB for monaural fitting.