Early intervention for children with unilateral and mild bilateral degrees of hearing loss.

Some children with unilateral hearing loss or mild bilateral hearing loss are at risk for developmental delays, educational difficulties, and other adverse effects. However, these children face several challenges in receiving services that can prevent such problems. Many do not meet existing eligibility requirements for early intervention services in their state. Information disseminated to professionals and parents often does not convey the significance of unilateral and mild bilateral hearing loss. Some professionals indicate that there are insufficient guidelines defining appropriate intervention services for these children. Factors that influence developmental outcomes in this population are not well understood, making it difficult to determine which children can benefit from intervention services. Additional data are needed about how to minimize or prevent adverse outcomes in these children. This article presents suggestions for intervention and future research that were developed by participants of the 2005 National Workshop on Mild and Unilateral Hearing Loss.

Hearing screening and diagnostic evaluation of children with unilateral and mild bilateral hearing loss.

More than 90% of newborns in the United States are now being screened for hearing loss. A large fraction of cases of unilateral hearing loss and mild bilateral hearing loss are not currently identified through newborn hearing screening. This is of concern because a preponderance of research has demonstrated that unilateral hearing loss and mild bilateral hearing loss can lead to developmental delays and educational problems for some children. To help address this probable underidentification of unilateral hearing loss and mild bilateral hearing loss among infants and children, the Centers for Disease Control and Prevention Early Hearing Detection and Intervention program and the Marion Downs Hearing Center convened a workshop in Breckenridge, Colorado, in July 2005. During this workshop, several issues related to screening and diagnosing unilateral hearing loss and mild bilateral hearing loss were identified, as well as recommendations for future research in this area. Issues identified included the lack of standardized definitions for permanent unilateral hearing loss and mild bilateral hearing loss; the use of screening protocols that are primarily designed to identify bilateral and unilateral hearing losses of a moderate degree or greater (eg, above 40 dB); calibration of screening equipment; availability of facilities that can provide the full range of audiologic, diagnostic, and management services to this pediatric population; and an overall lack of awareness by many professionals and families about the potential effect of unilateral hearing loss and mild bilateral hearing loss. Suggestions for future research, such as identifying ways to improve the identification of cases of unilateral hearing loss and mild bilateral hearing loss, were also discussed.

Amplification considerations for children with minimal or mild bilateral hearing loss and unilateral hearing loss.

Children with minimal or mild bilateral hearing loss and unilateral hearing loss are at higher risk for academic, speech-language, and social-emotional difficulties than their normal hearing peers. The choice to fit infants with moderate or greater degrees of bilateral hearing loss has been standard practice for most clinicians, but for those with minimal or mild bilateral hearing loss or unilateral hearing loss, the fitting of hearing technology must be based on limited data. Evidence does not yet exist to support all the management decisions that an audiologist must make upon identifying an infant with minimal or mild bilateral hearing loss or unilateral hearing loss. It is not yet known which children are at the greatest risk for educational problems nor is it known if the provision of early amplification in this population will help a child avoid later difficulties. Some of these considerations and current hearing technology options for children with minimal or mild bilateral hearing loss or unilateral hearing loss are reviewed in this article.

Mismatch negativity in children with autism and typical development.

Children with autism are often characterized as having abnormalities in auditory processing. This study examined automatic and active processing of simple auditory stimuli in children using a component of event related potentials, the mismatch negativity (MMN). Amplitude of MMN in children with autism was significantly smaller than in children with typical development in unattended conditions. However, children with autism exhibited a typical amplitude MMN when attending to the stimuli. Receptive language and MMN were not related in children with autism. Findings support the idea of abnormal automatic auditory processing by children with autism. Auditory discrimination of infrequent changes in streams of sounds appears to be accomplished through a different mechanism than in typical children, specifically through the investment of attention.

Early otitis media with effusion, hearing loss, and auditory processes at school age.

OBJECTIVES: To examine the effect of conductive hearing loss (HL) secondary to otitis media with effusion (OME) in the first 3 years of life on physiologic, peripheral, and higher-order behavioral auditory measures examined at school age. METHODS: Peripheral hearing sensitivity for conventional and extended high-frequency audiometric ranges, physiologic (distortion product otoacoustic emissions, contralateral and ipsilateral acoustic middle ear muscle reflexes), auditory brain stem response (ABR), and higher-order auditory processing measures (masking level difference; Virtual Auditory Localization, Speech Intelligibility Gain; adaptive Pediatric Speech Intelligibility task) were examined at the end of the second grade of elementary school in two cohorts (North Carolina, N = 73, and New York, N = 59). All participants (mean age, 8 years) were followed prospectively in infancy and early childhood (7 to 39 months) for middle ear status and hearing loss (using pneumatic otoscopy/tympanometry and repeated conditioned behavioral audiometric response procedures). Multivariate analyses were conducted to address whether early OME and early conductive HL were related to physiologic, peripheral, and higher-order auditory processes. RESULTS: Early hearing loss and OME were significantly associated with peripheral hearing at school age; extended high-frequency thresholds accounted for the result. Similarly, hearing loss in early life and OME were significantly associated with the acoustic middle ear muscle reflex: The contralateral stimulation condition accounted for the association. Significant associations with both early OME and early HL were also found for the auditory brain stem response measure and were explained by the correlations between early hearing loss and the ABR Wave V latency but not other ABR indices. There were no reliable associations between either early OME or early HL on any other auditory processes evaluated at the end of second grade. CONCLUSIONS: Extended high-frequency hearing and brain stem auditory pathway measures in childhood were significantly associated with children's experiences with OME and hearing loss from 7 to 39 months of age. However, no significant associations were found for psychoacoustic measures of binaural processing or a behavioral adaptive speech-in-noise test at school age.

Peripheral audition of children on the autistic spectrum.

OBJECTIVE: To determine whether the peripheral audition of a group of children comprehensively diagnosed as being on the autistic spectrum was quantitatively different from that of a matched group of typically developing children. METHODS: Thirty-seven children with autism and an equal number of control participants matched for chronological age within 6 mo were examined by means of behavioral and physiologic measures of auditory function. All participants had normal hearing (thresholds <15 dB HL; 0.25 to 8 kHz) and normal middle ear function by quantitative tympanometry. Conventional behavioral audiometry, a computer-assisted threshold assessment procedure, acoustic middle ear muscle reflex thresholds, and evoked otoacoustic emissions (both transient and distortion product) tests were administered to both groups. RESULTS: No significant differences between children with autism and those developing typically on any behavioral or physiologic measure of peripheral auditory function were found. CONCLUSIONS: There was no evidence of intrinsic differences in the peripheral auditory mechanism of children with autism that would account for the auditory processing disorders and sound sensitivity that are commonly reported in this population.

A multicenter evaluation of how many infants with permanent hearing loss pass a two-stage otoacoustic emissions/automated auditory brainstem response newborn hearing screening protocol.

OBJECTIVE: Ninety percent of all newborns in the United States are now screened for hearing loss before they leave the hospital. Many hospitals use a 2-stage protocol for newborn hearing screening in which all infants are screened first with otoacoustic emissions (OAE). No additional testing is done with infants who pass the OAE, but infants who fail the OAE next are screened with automated auditory brainstem response (A-ABR). Infants who fail the A-ABR screening are referred for diagnostic testing to determine whether they have permanent hearing loss (PHL). Those who pass the A-ABR are considered at low risk for hearing loss and are not tested further. The objective of this multicenter study was to determine whether a substantial number of infants who fail the initial OAE and pass the A-ABR have PHL at approximately 9 months of age. METHODS: Seven birthing centers with successful newborn hearing screening programs using a 2-stage OAE/A-ABR screening protocol participated. During the study period, 86634 infants were screened for hearing loss at these sites. Of those infants who failed the OAE but passed the A-ABR in at least 1 ear, 1524 were enrolled in the study. Data about prenatal, neonatal, and socioeconomic factors, plus hearing loss risk indicators, were collected for all enrolled infants. When the infants were an average of 9.7 months of age, diagnostic audiologic evaluations were done for 64% of the enrolled infants (1432 ears from 973 infants). RESULTS: Twenty-one infants (30 ears) who had failed the OAE but passed the A-ABR during the newborn hearing screening were identified with permanent bilateral or unilateral hearing loss. Twenty-three (77%) of the ears had mild hearing loss (average of 1 kHz, 2 kHz, and 4 kHz < or =40-decibel hearing level). Nine (43%) infants had bilateral as opposed to unilateral loss, and 18 (86%) infants had sensorineural as opposed to permanent conductive hearing loss. CONCLUSIONS: If all infants were screened for hearing loss using the 2-stage OAE/A-ABR newborn hearing screening protocol currently used in many hospitals, then approximately 23% of those with PHL at approximately 9 months of age would have passed the A-ABR. This happens in part because much of the A-ABR screening equipment in current use was designed to identify infants with moderate or greater hearing loss. Thus, program administrators should be certain that the screening program, equipment, and protocols are designed to identify the type of hearing loss targeted by their program. The results also show the need for continued surveillance of hearing status during childhood.

Auditory brainstem responses in young males with Fragile X syndrome.

Fragile X syndrome (FXS) is the most common inherited cause of mental retardation resulting in developmental delays in males. Atypical outer ear morphology is characteristic of FXS and may serve as a marker for abnormal auditory function. Despite this abnormality, studies of the hearing of young males with FXS are generally lacking. A few studies have suggested that a significant proportion of individuals with FXS demonstrate prolonged auditory brainstem response (ABR) latencies. The purpose of this study was to determine whether young males with FXS display atypical auditory brainstem function compared to typically developing males when conductive and sensorineural hearing loss are ruled out as possible contributors to atypical findings. Participants were 23 males with FXS, 21 typically developing males who were matched for developmental age, and 17 typically developing males who were matched for chronological age. A battery of tests to assess peripheral hearing, cochlear function, and auditory pathway integrity through the level of the brainstem was completed. Males with FXS were similar to typically developing males who were matched for developmental age level or chronological age level on all measures. They had normal hearing sensitivity and middle ear function and scored similar to the typically developing children on the measures of auditory brainstem pathway integrity. In summary, ABRs in young males with FXS were within normal limits.

A multisite study to examine the efficacy of the otoacoustic emission/automated auditory brainstem response newborn hearing screening protocol: introduction and overview of the study.

PURPOSE: This article is the 1st in a series of 4 articles on a recently completed multistate study of newborn hearing screening. METHOD: The study examined the efficacy of the 2-stage otoacoustic emission/automated auditory brainstem response (OAE/A-ABR) protocol for identifying hearing loss in newborns. RESULTS: The study found that the 2-stage OAE/A-ABR protocol did miss a significant number of babies who exhibited a permanent hearing loss by 1 year of age. Three subsequent articles will describe the research design and results in detail, discuss the behavioral assessment of infants, and summarize the implications of the study for policy, practice, and research.

A multisite study to examine the efficacy of the otoacoustic emission/automated auditory brainstem response newborn hearing screening protocol: research design and results of the study.

PURPOSE: Most newborns are screened for hearing loss, and many hospitals use a 2-stage protocol in which all infants are screened first with otoacoustic emissions (OAEs). In this protocol, no additional testing is done for those passing the OAE screening, but infants failing the OAE are also screened with automated auditory brainstem response (A-ABR). This study evaluated how many infants who failed the OAE and passed the A-ABR had permanent hearing loss (PHL) at 8-12 months of age. METHOD: A total of 86,634 infants were screened at 7 birthing centers using a 2-stage OAE/A-ABR hearing screening protocol. Of infants who failed the OAE but passed the A-ABR, 1,524 were enrolled in the study. Diagnostic audiologic evaluations were performed on 64% of the enrolled infants (1,432 ears from 973 infants) when they were 8-12 months old. RESULTS: Twenty-one infants (30 ears) who passed the newborn A-ABR hearing screening were identified with PHL when they were 8-12 months old. Most (71%) had mild hearing loss. CONCLUSIONS: If all infants were screened for hearing loss using a typical 2-stage OAE/A-ABR protocol, approximately 23% of those with PHL at 8-12 months of age would have passed the A-ABR.

A multisite study to examine the efficacy of the otoacoustic emission/automated auditory brainstem response newborn hearing screening protocol: results of visual reinforcement audiometry.

PURPOSE: This 3rd of 4 articles on a study of the efficacy of the 2-stage otoacoustic emission/automated auditory brainstem response (OAE/A-ABR) newborn hearing screening protocol describes (a) the behavioral audiometric protocol used to validate hearing status at 8-12 months of age, (b) the hearing status of the sample, and (c) the success of the visual reinforcement audiometry (VRA) protocol across 7 sites. METHOD: A total of 973 infants who failed OAE but passed A-ABR, in one or both ears, during newborn screening were tested with a VRA protocol, supplemented by tympanometry and OAE screening at age 8-12 months. RESULTS: VRA audiograms (1.0, 2.0, and 4.0 kHz) were obtained for 1,184 (82.7%) of the 1,432 study ears. Hearing loss was ruled out in another 100 ears by VRA in combination with OAE, for a total of 88.7% of the study sample. Permanent hearing loss was identified in 30 ears of 21 infants. Sites differed in their success with the VRA protocol. CONCLUSIONS: Continued monitoring of hearing beyond the newborn period is an important component of early detection of hearing loss. Using a structured protocol, VRA is an appropriate test method for most, but not all, infants. A battery of test procedures is often needed to adequately delineate hearing loss in infants. Examiner experience appears to be a factor in successful VRA.

A multisite study to examine the efficacy of the otoacoustic emission/automated auditory brainstem response newborn hearing screening protocol: recommendations for policy, practice, and research.

PURPOSE: This article examines whether changes in hearing screening practices are warranted based on the results of the recent series of studies by J. L. Johnson, K. R. White, J. E. Widen, J. S. Gravel, B. R. Vohr, M. James, T. Kennalley, A. B. Maxon, L. Spivak, M. Sullivan-Mahoney, Y. Weirather, and S. Meyer (Johnson, White, Widen, Gravel, James, et al., 2005; Johnson, White, Widen, Gravel, Vohr, et al., 2005; White et al., 2005; Widen et al., 2005) that found a significant number of infants who passed an automated auditory brainstem response (A-ABR) screening after failing an initial otoacoustic emission (OAE) screening later were found to have permanent hearing loss in one or both ears. METHOD: Similar to the approach used by F. H. Bess and J. Paradise (1994), this article addresses the public health tenets that need to be in place before screening programs, or in this case, a change in screening practice (use of a 2-step screening protocol) can be justified. RESULTS: There are no data to suggest that a 2-step OAE/A-ABR screening protocol should be avoided. CONCLUSION: Research is needed before any change in public policy and practice surrounding current early hearing detection and intervention programs could be supported.

Revisiting loudness measures in children using a computer method of cross-modality matching (CMM).

The test efficiency and reliability of loudness assessment using a computer-controlled method of cross-modality matching (CMM) between line length and loudness was investigated in children 4 to 12 years with normal hearing or mild to severe degrees of sensorineural hearing loss. Adult listeners with normal hearing served as a comparison group. Computer-generated visual and acoustic stimuli were used to derive individual loudness data. Children and adults with normal hearing presented with similar loudness functions, while children with sensorineural hearing loss had steeper functions than their normal-hearing counterparts. Retest data supported reliability of the CMM method with children within the current study and between previous studies performed with a similar, but manual, method. The computer CMM approach proved more time efficient than the manual one, halving the test time. The CMM loudness task in a computerized version may have potential in a research or clinical setting, in particular for individualizing hearing aid fittings with children.

Simulated conductive hearing loss in children.

Otitis media with effusion (OME) often results in hearing loss for children with the condition. In order to provide appropriate and effective audiologic management, it is important to understand the impact of OME on speech recognition ability when hearing loss is present. This study examined the speech recognition abilities of normal-hearing six- and seven-year-old children (n = 12) and adults (n = 12) using monosyllabic words and nonsense syllables presented at two levels of simulated conductive hearing loss characteristic of OME. Average speech recognition scores decreased as the degree of simulated conductive hearing loss increased. Both age groups scored significantly poorer for nonsense syllables than for monosyllabic words. In general, the children performed more poorly than the adults with the exception of the easiest listening condition for word stimuli. Furthermore, children appeared less able than adults to use their knowledge of familiar words to improve performance. These findings suggest that rehabilitative strategies may best be focused on combining familiarization techniques and amplification options.

Otitis media, hearing loss, and language learning: controversies and current research.

This article reviews research on the possible linkage of otitis media with effusion (OME) to children's hearing and development, identifies gaps, and directions for research, and discusses implications for healthcare practices. About half of children with an episode of OME experience a mild hearing loss while about 5-10% of children have moderate hearing loss. Recent prospective and randomized clinical trials suggest none to very small negative associations of OME to children's later language development. Based on both retrospective and prospective longitudinal studies, associations between OME and perceiving speech in noise and tasks that require equal binaural hearing have been reported but have not been adequately studied with regard to functional outcomes. Thus, on average, for typically developing children, OME may not be a substantial risk factor for later speech and language development or academic achievement. However, these conclusions should be interpreted cautiously, since most of these studies used OME rather than hearing loss as the independent variable (although hearing loss rather than OME is hypothesized to affect language development) and many studies did not control for important confounding variables such as socioeconomic status (SES).

Communication options for children with hearing loss.

This article examines the communication options that are available for use within families of infants and young children who are hard-of-hearing or deaf. The need for language development, regardless of the specific communication mode, is stressed. The demands of the current environment of early identification and intervention often put families in a position of needing to decide among communication methods before they are fully knowledgeable and/or emotionally ready. Specific communication options are delineated and considered within a continuum of spoken and visual language. Available research related to early acquisition of language by infants and young children who are hard-of-hearing and deaf is reviewed; outcomes, when available, are presented for specific methods from reports of older children. Factors that influence families' decisions regarding the selection of a communication option are highlighted in the context of the existing literature. An ongoing evaluative process that respects the choices of families is advocated; a context in which change(s) in communication mode through childhood is viewed as a positive circumstance. The ultimate goal in the selection of any communication approach is to ensure that infants and young children who are hard of hearing or deaf and their families are language proficient and fluent communicators.

"Auditory neuropathy": physiologic and pathologic evidence calls for more diagnostic specificity.

The term "auditory neuropathy" is being used in a rapidly increasing number of papers in the audiology/otolaryngology literature for a variety of individuals (mostly children) who fulfill the following criteria: (1) understanding of speech worse than predicted from the degree of hearing loss on their behavioral audiograms; (2) recordable otoacoustic emissions and/or cochlear microphonic; together with (3) absent or atypical auditory brain stem responses. Because of the general lack of anatomic foundation for the label "auditory neuropathy" as currently used, we review the anatomy of the auditory pathway, the definition of neuropathy and its demyelinating, axonal, and mixed variants. We submit that the diagnostic term "auditory neuropathy" is anatomically inappropriate unless patients have documented evidence for selective involvement of either the spiral ganglion cells or their axons, or of the 8th nerve as a whole. In view of biologic differences between peripheral nerves and white matter tracts in the brain, the term "auditory neuropathy" is inappropriate for pathologies affecting the central auditory pathway in the brainstem and brain selectively. Published reports of patients with "auditory neuropathy" indicate that they are extremely heterogeneous in underlying medical diagnosis, age, severity, test results, and that only a small number have undergone the detailed investigations that would enable a more precise diagnosis of the locus of their pathologies. The electrophysiology of peripheral neuropathies and the deficits expected with pathologies affecting the hair cells, spiral ganglion cells and their axons (auditory neuropathy sensu stricto), and brain stem relays are reviewed. In order to serve patients adequately, including potential candidates for cochlear implants, and to increase knowledge of auditory pathologies, we make a plea for more comprehensive evaluation of patients who fulfill the currently used audiologic criteria for "auditory neuropathy" in an effort to pinpoint the site of their pathologies. We suggest that the term auditory neuropathy be limited to cases in which the locus of pathology is limited to the spiral ganglion cells, their processes, or the 8th nerve, and that the term neural hearing loss be considered for pathologies that affect all higher levels of the auditory pathway, from the brainstem to the auditory cortex.