Twin study of central auditory processing disorder

We compared auditory, cognitive, and language test results in a pair of dizygotic twins, one of whom showed symptoms of central auditory processing disorder (CAPD). Results highlight the importance of testing binaural function. In particular, electrophysiologic measures of dichotic listening effectively demonstrated the auditory-specific nature of this child's listening problems. The importance of a thorough and comprehensive evaluation of children suspected of CAPD is stressed.     

Assessment of auditory processing in 6-year-old language-impaired children

The performance of a group of twenty 6-year-old children with specific language impairment (SLI) on several behavioural auditory tests was compared to that of a group of twenty age-matched control children. The auditory test battery used in this study consisted of the following tests: a speech-in-noise test, a filtered speech test, a binaural fusion test, a frequency pattern test, a duration pattern test, a temporal integration test, an auditory word discrimination test, an auditory synthesis test, an auditory closure test and a number recall test. Our results show that the SLI children obtained scores on almost all tests that were significantly lower than those of the control group. Many of the basic auditory processing measures in our test battery correlated significantly with receptive and language scores, suggesting a (causal) relationship between auditory processing and language proficiency. Results from discriminant function analyses do not warrant deleting one or more tests from the test battery yet (with the exception of the auditory synthesis test and the temporal integration test, for which we did not find significant group effects). At present, we are conducting experiments with older (SLI and control) children and adults to find whether the significant performance deficits of the SLI children are also found in older SLI children, and to determine the influence of maturational effects on these auditory tests.     

Diagnosis of amblyaudia in children referred for auditory processing assessment

Children (n?=?141) referred to 5 clinical sites for auditory processing disorder assessment were tested with two dichotic listening tests, one with word pairs and the other with pairs of digits, as part of a comprehensive diagnostic battery. Scores from the Randomized Dichotic Digits Test and the Dichotic Words Test were compared to age-appropriate norms and used to place children into one of four diagnostic categories (normal, dichotic dysaudia, amblyaudia, or amblyaudia plus) or to identify them as undiagnosed. Results from the two dichotic tests led to diagnosis of 56% of the children tested, leaving 44% undiagnosed. When results from a third dichotic listening test were used as a tie-breaker among originally undiagnosed children, a total of 79% of the children’s scores were placed into diagnostic categories (13% normal, 19% dichotic dysaudia, 35% amblyaudia, 12% amblyaudia plus). Amblyaudia, a binaural integration deficit evident only from dichotic listening test results, was most prevalent (35%?+?12%?=?47%) in this population of children suspected of auditory processing weaknesses. Since amblyaudia responds to treatment with Auditory Rehabilitation for Interaural Asymmetry (ARIA), clinicians are guided through the protocol for identifying diagnostic categories so that they can make appropriate referrals for rehabilitation.     

Association between language development and auditory processing disorders

IntroductionIt is crucial to understand the complex processing of acoustic stimuli along the auditory pathway; comprehension of this complex processing can facilitate our understanding of the processes that underlie normal and altered human communication.AimTo investigate the performance and lateralization effects on auditory processing assessment in children with specific language impairment (SLI), relating these findings to those obtained in children with auditory processing disorder (APD) and typical development (TD).Material and methodsProspective study. Seventy-five children, aged 6-12 years, were separated in three groups: 25 children with SLI, 25 children with APD, and 25 children with TD. All went through the following tests: speech-in-noise test, Dichotic Digit test and Pitch Pattern Sequencing test.ResultsThe effects of lateralization were observed only in the SLI group, with the left ear presenting much lower scores than those presented to the right ear. The inter-group analysis has shown that in all tests children from APD and SLI groups had significantly poorer performance compared to TD group. Moreover, SLI group presented worse results than APD group.ConclusionThis study has shown, in children with SLI, an inefficient processing of essential sound components and an effect of lateralization. These findings may indicate that neural processes (required for auditory processing) are different between auditory processing and speech disorders.     

Central auditory processes evaluated with psychoacoustic tests in normal children

ObjectiveTo identify the natural tendencies of hits and calculate the cutoff for a test group of central auditory processes (CAP): binaural fusion, filtered words, dichotic digits, frequency patterns and duration patterns and ambient sounds in normal 5-, 7-, 9- and 11-year-old children.Material and methodsWe studied 369 children (738 ears) who attend public schools in Puebla City, administering 6 CAP tests (two binaural and four monaural); we used an audiometer at 50 dB SL re-threshold at 1 kHz, from a CD recorded at the CCECADET-UNAM-INR (Centre for Applied Science and Technological Development at the National Autonomous University of Mexico and the National Institute for Rehabilitation).ResultsWe determined the cutoff points for the six tests.ConclusionThis information represents an advance in the normative standards in the field of psychoacoustic tests for CAP in Spanish and in the socio-educational context prevalent in Mexico. It is important to evaluate these results against CAP disorders.     

The auditory processing battery: survey of common practices

A survey of auditory processing (AP) diagnostic practices was mailed to all licensed audiologists in the State of Maryland and sent as an electronic mail attachment to the American Speech-Language-Hearing Association and Educational Audiology Association Internet forums. Common AP protocols (25 from the Internet, 28 from audiologists in Maryland) included requiring basic audiologic testing, using questionnaires, and administering dichotic listening, monaural low-redundancy speech, temporal processing, and electrophysiologic tests. Some audiologists also administer binaural interaction, attention, memory, and speech-language/psychological/educational tests and incorporate a classroom observation. The various AP batteries presently administered appear to be based on the availability of AP tests with well-documented normative data. Resources for obtaining AP tests are listed.     

Normal and learning disabled children's central auditory processing skills: an experimental test battery

The performance of normal children (N = 13) and learning disabled children (N = 26) on an experimental battery of central auditory processing (CAP) tasks was examined. The battery included low-pass filtered speech (LPFS), binaural fusion (BF), time-compressed speech (TC), and dichotic monosyllables (DM) tests. The learning disabled subjects were classified as having normal (LD/N) or significantly impaired (LD/LD) auditory perceptual skills on the basis of a pretest battery of auditory language tests. The normal (N/N) subjects and nonauditory learning disabled (LD/N) subjects tended to perform alike across measures. The auditorily impaired (LD/LD) subjects tended to perform significantly poorer than their normal agemates. The results emphasized the heterogeneity of the learning disabled population. In addition, the results suggested a potentially useful "at risk" criterion when a CAP test battery is used in the assessment of auditory perceptual impairment among children.     

Utilization of a central auditory processing test battery in evaluating residual effects of decompression sickness.

Six professional divers were examined as patients who presented peripheral auditory, vestibular, or central symptoms attributed to incidents which occurred while diving. Each diver received a central auditory processing (CAP) test battery consisting of: (1) a dichotic sentence listening task, (2) a monotic filtered word task, (3) a binaural fusion task, and (4) an alternating speech task. The CAP test results, in all cases substantiated other neurological/vestibular test battery results which we have reported in detail previously.     

Central auditory processing assessment

As the acoustic information travels within the central auditory nervous system, the processing of the signal undergoes several levels of serial and parallel "bottom-up" processing influenced by high level cognitive "top-down" processes. Because the multiple location of the operational sites, the central auditory deficits are frequently quite subtle and need a test battery approach to be identified. Each of the four principal processes has at least to be tested: the closure task, the dichotic ability, the temporal ordering task and the binaural interaction function. The purpose of this review is to provide an overview of the psychoacoustic test procedures of identifying lesions or dysfunction's in the central auditory system.     

Central auditory processing: behavioral and electrophysiological assessment of children and adolescents diagnosed with stroke

IntroductionCentral auditory processing refers to the efficiency and effectiveness with which the central nervous system uses auditory information: it may be altered in neurological disorders and brain injuries, such as strokes. However, despite evidence of probable alterations in the pediatric population, functional abilities and post-stroke limitations are still not well documented in the literature.ObjectiveTo analyze the findings of the electrophysiological and behavioral evaluations of central auditory processing of children and adolescents diagnosed with stroke from a reference outpatient clinic, as well as to investigate possible associations with the variables: type and location of the stroke and age group.MethodsThe present study is characterized as comparative cross-sectional. The sample, for convenience, included individuals aged 7–18 years divided into two groups: study group, composed of individuals with a diagnosis of stroke, and control group, composed of individuals with typical development. The evaluation consisted of the following procedures: anamnesis, basic audiological evaluation, behavioral evaluation of the auditory processing disorder (dichotic digit test, dichotic consonant-vowel, synthetic sentence identification/pediatric speech intelligibility, gaps in noise, pitch pattern sequence, masking level difference), and electrophysiological evaluation (P300 and mismatch negativity).ResultsNineteen children and adolescents were included in the study group. The control group was composed of 19 children and adolescents with typical development. In the comparison between the groups, a worse performance is observed for the study group in all the evaluated tests, behavioral and electrophysiological. In the behavioral evaluation of central auditory processing, there was a statistical difference for all tests, except for masking level difference and dichotic digit test, binaural separation step on the left. In the electrophysiological evaluation, there was a statistical difference in the latency of mismatch negativity and P300. No associations were found between the behavioral and electrophysiological findings and the location of the stroke and age group variables.ConclusionChildren and adolescents diagnosed with stroke present a worse performance in the electrophysiological and behavioral evaluations of central auditory processing when compared to a control group.     

疑似听觉处理障碍儿童案例研究

目的本文介绍了中枢听觉功能测试方法，探讨了对听觉处理障碍儿童的诊断和处理原则。方法选择3例疑似听觉处理障碍儿童作为研究案例，进行系统的听力学，教育心理学、言语病理学测试和听觉中枢处理评估。结果在随机间隔探测测试和空间噪音听力测试（Iistening in spatializecl noise test，LISN）中，得分低于同龄组的平均值超过5个标准差；高一提示信号的LISN测试结果显示，数值低于平均值超过2个标准差。结论中枢听觉处理测试序列说明此3例儿童存在双耳听觉处理缺陷。通过改善教室的信噪比，应用听觉闭合训练、听觉定位和辨别训练，加强语言处理技能训练，能够使这3名儿童受益。     

Identification of binaural integration deficits in children with the Competing Words Subtest: standard score versus interaural asymmetry

The Competing Words Subtest is a commonly used dichotic listening test for assessing binaural integration in children suspected of having an auditory processing disorder. In 124 children, standard scores from the subtest suggested a binaural integration deficit in 23% of the children tested. Because standard scores are derived from the combined scores of both ears during the test, children with normal performance in one ear and weak performance in the other ear may be overlooked. For these children, a measure of interaural asymmetry may be a more sensitive indicator of a binaural integration deficit. When an age-appropriate criterion for interaural asymmetry from the Competing Words Subtest was used, the incidence of a binaural integration deficit increased to 51% of the children tested. Four typical patterns of dichotic listening performance were identified based on results from the two scoring techniques.     

Identification of binaural integration deficits in children with the Competing Words Subtest: standard score versus interaural asymmetry

The Competing Words Subtest is a commonly used dichotic listening test for assessing binaural integration in children suspected of having an auditory processing disorder. In 124 children, standard scores from the subtest suggested a binaural integration deficit in 23% of the children tested. Because standard scores are derived from the combined scores of both ears during the test, children with normal performance in one ear and weak performance in the other ear may be overlooked. For these children, a measure of interaural asymmetry may be a more sensitive indicator of a binaural integration deficit. When an age-appropriate criterion for interaural asymmetry from the Competing Words Subtest was used, the incidence of a binaural integration deficit increased to 51% of the children tested. Four typical patterns of dichotic listening performance were identified based on results from the two scoring techniques.     

The binaural interaction component (BIC) in children with central auditory processing disorders (CAPD)

The detection of binaural interaction is of diagnostic interest in patients with central auditory processing disorders (CAPDs), as binaural hearing tasks are frequently affected in these patients. Owing to the comorbidity associated with disorders such as an attention-deficit hyperactivity disorder, pathological results in subjective tests often show extra-auditory factors such as reduced attention rather than impaired central auditory function. Therefore, objective measures for auditory processing disorders are essential. The binaural interaction component (BIC), which is the arithmetical difference between the sum of the monaurally evoked auditory potentials of each ear and the binaurally evoked brainstem potentials, has been used as an objective measure of binaural interaction in humans. BIC measurements can therefore be considered as a possible diagnostic tool in CAPD patients. One aim of the present study was to examine whether and to what extent BIC measurements are capable of differentiating between normal children and children 'at risk for CAPD'. BIC measurements were performed on 17 children at risk for CAPD and in a group of 25 children with normal results in the central audiometric tests used. Using the presence or absence of clearly demonstrable BIC waveforms as an indication of whether a CAPD is present or not, a sensitivity and specificity of 76% could be achieved. We conclude that BIC measurements might be of some diagnostic value in CAPD patients.     

Central auditory deficits and temporal-lobe lesions.

The capacity of auditory pathways from the weak ear (ear with the suppressed score in a dichotic listening test) to transmit speech information to the cortical processing areas was examined on 10 patients with unilateral temporal-lobe lesions. Three lines of evidence were developed to suggest that auditory pathways from the weak ear and speech information presented to the weak ear are not completely suppressed during dichotic stimulation. Speech in the weak ear frequently interacts with competing speech information in the strong ear causing contrasting articulatory features from the two ears to be blended into a single response. Two models of unilateral central auditory deficits are discussed: ipsilateral-suppression and transmission-line.     

Identification of binaural integration deficits in children with the Competing Words Subtest: Standard score versus interaural asymmetry

The Competing Words Subtest is a commonly used dichotic listening test for assessing binaural integration in children suspected of having an auditory processing disorder. In 124 children, standard scores from the subtest suggested a binaural integration deficit in 23% of the children tested. Because standard scores are derived from the combined scores of both ears during the test, children with normal performance in one ear and weak performance in the other ear may be overlooked. For these children, a measure of interaural asymmetry may be a more sensitive indicator of a binaural integration deficit. When an age-appropriate criterion for interaural asymmetry from the Competing Words Subtest was used, the incidence of a binaural integration deficit increased to 51% of the children tested. Four typical patterns of dichotic listening performance were identified based on results from the two scoring techniques.