ARIA treatment benefits are related to severity of dichotic listening deficits in children.

PURPOSE: This study investigated the relationship between dichotic listening (DL) benefits from treatment with Auditory Rehabilitation for Interaural Asymmetry (ARIA) and the severity of DL deficits quantified prior to the onset of treatment. We hypothesized that children with more severe DL deficits would demonstrate greater benefits following ARIA. METHOD: A scale that quantifies deficit severity was applied to dichotic listening scores obtained before and after training with ARIA at multiple clinical sites (n = 92). Using multiple regression analyses, we evaluated the predictive effects of deficit severity on DL outcomes. RESULTS: Results demonstrated that deficit severity can predict benefits from ARIA, as measured by improvements in DL scores in both ears. CONCLUSION: ARIA is an adaptive training paradigm for improving binaural integration abilities in children with DL deficits. The results from this study suggest that children with more severe DL deficits achieve greater benefits from ARIA and that a severity scale may provide important clinical information for recommending intervention.

A Nonsense Consonant-Vowel-Consonant Word Test to Assess Auditory Processing.

BACKGROUND: Dichotic listening (DL), or how the two ears work together as a team, is often used in the assessment of auditory processing disorders in both children and adults. Currently, the battery of dichotic tests includes stimuli containing words, digits, and nonsense consonant-vowel syllables. Single-syllable nonsense words are of particular use in assessing processing abilities because they can evaluate auditory processing without a listener's dependence on linguistic knowledge. Therefore, nonsense words may assess auditory processes independently of previous vocabulary knowledge. PURPOSE: This study is designed to assess the clinical applicability and face validity of a nonsense word DL test in a young adult population. RESEARCH DESIGN: This study included an experimental design to investigate the performance of young adult listeners on a Dichotic Nonsense Word (DNW) test spoken by a male and female speaker. The results were compared with one study that investigated young adult listener's performance on dichotic tests of English words. STUDY SAMPLE: A total of 100 young adult participants were recruited from the School of Health and Rehabilitation Sciences at the University of Pittsburgh to participate in the study. The participants ranged in age from 20 to 30, with an average age of 23, and all participants had normal hearing. DATA COLLECTION AND ANALYSIS: DL performance was measured in all participants using the Dichotic Words Test (DWT) and the newly developed DNW test. Kolmogorov-Smirnoff tests of normality were used to assess distribution of right- and left-ear scores. Criterion cutoff scores were determined for the percent correct scores in the nondominant ear and dominant ear and for ear advantage. RESULTS: Scores were significantly different between the two tests in the right ear, Z = -8.258, p < 0.001, and in the left ear, Z = -8.471, p < 0.001. Scores within each test were higher for the right ear than for the left ear, and scores for both ears were significantly lower on the DNW test than for the DWT. Ear advantage scores from the DNW test were significantly larger than those obtained from the DWT. The low and high 95% criterion cutoff ranges for the DNW test were considerably wider than the 95% criterion cutoff ranges for the DWT. CONCLUSIONS: Results indicate that the new DNW test may be a useful clinical tool within a test battery for evaluating auditory processing skills independent of vocabulary knowledge.

Dichotic listening in children: age-related changes in direction and magnitude of ear advantage.

Children between the ages of 5 and 12 years were tested with dichotic listening tests utilizing single syllable words and random presentations of digits. They produced a higher prevalence of left ear dominance than expected, especially among right-handed children when tested with words. Whether more children demonstrate the LEA because of right hemisphere dominance for language or because there is less stability in ear advantage direction at younger ages cannot be fully resolved by this study. When ear advantages were measured by subtracting each child's lower score from the higher score without regard to right or left direction, an age-related trend toward lower measures of ear advantage was evident. This trend was greater for dichotic words than for dichotic digits. Structural factors that may be related to these results and possible influences of attention and verbal workload on the two kinds of dichotic stimuli are discussed.

Recognition of randomly presented one-, two-, and three-pair dichotic digits by children and young adults.

PURPOSE: To establish normative data for children and to characterize developmental differences in performance with the free recall version of the Randomized Dichotic Digits Test. RESEARCH DESIGN: Group comparison of behavioral data derived from administration of the Randomized Dichotic Digits Test. STUDY SAMPLE: Children from 10 to 18 years of age (167) and young adults from 19 to 28 years of age (50). RESULTS: Performance improved with age across all types of digit pairs, especially in the left ear, leading to smaller interaural asymmetries among older participants. A left-ear advantage was produced by 39 subjects (18%), only two of whom were left-handed. Normative data are reported for right and left ear scores and for interaural asymmetry (percent correct difference between the two ears) under one-, two-, and three-pair conditions of the test and for interaural asymmetry across the entire test. A unilateral deficit was identified in children (15.5%) and young adults (12%) for the left ear and in children (11.3%) and young adults (6%) for the right ear. A bilateral deficit was also identified in children (6.5%) and young adults (6%). CONCLUSIONS: This test may be useful as part of the clinical battery for identifying binaural integration weaknesses and referring individuals for auditory rehabilitation for interaural asymmetry (ARIA).

Auditory rehabilitation for interaural asymmetry: preliminary evidence of improved dichotic listening performance following intensive training.

Children with dichotic left ear deficits received intensive training in phase I and phase II clinical trials designed to establish the efficacy of directly training dichotic listening. Dichotic verbal material was presented in the sound field with intensity adjusted separately for each speaker. Output from the right-sided speaker was initially 20-30 db HL lower than for the left-sided speaker, resulting in excellent performance in the left ear. Intensities were adaptively adjusted throughout training in 1, 2, and 5-dB steps in order to keep performance high across dichotic tasks. In both phase I (n=8) and phase II (n=13) trials, children demonstrated significant gains in dichotic left ear performance after training. In phase II, children also demonstrated significant gains in right ear performance. Overall results from the two trials support the feasibility of this training approach for improving a larger than normal interaural asymmetry on dichotic listening tasks. Significant improvements in language comprehension and word recognition in phase II suggest that this type of training may also facilitate language skills in some children.

Dichotic listening deficits in children with dyslexia.

Several auditory processing deficits have been reported in children with dyslexia. In order to assess for the presence of a binaural integration type of auditory processing deficit, dichotic listening tests with digits, words and consonant-vowel (CV) pairs were administered to two groups of right-handed 11-year-old children, one group diagnosed with developmental dyslexia and an age-matched control group. Dyslexic children performed more poorly than controls from their left ears when listening to digits and words and from their right ears when listening to CVs. Direction of ear advantage varied across individuals in both groups when tested with digits and CVs, but ear advantage was stable with words. Several factors that may have contributed to inconsistencies in direction of ear advantage are discussed. When the children were tested in a directed response mode, degree of ear advantage differed significantly between groups with both words and digits. More dyslexic than control children demonstrated clinically significant reductions in dichotic listening performance, but no uniform pattern of deficit emerged. Only the double correct score and the left ear score with CV pairs were predictive of word recognition performance in dyslexic children. Binaural integration deficits are present in some children with dyslexia. Auditory processing disorder assessment may help delineate factors that underlie or are associated with reading impairment in this population.

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.

Differential attention effects on dichotic listening.

The role of attention in the differentiation of auditory processing disorders from attention deficit disorders is gaining considerable interest in both the clinical and research arenas. It has been well established that when attention is directed to one ear or the other on traditional dichotic tests, performance can be altered. However, preliminary studies in our laboratory have shown that dichotic fusion paradigms are resistant to shifts in ear performance associated with changes in attention. The purpose of this study was to assess the performance of normal listeners on a dichotic consonant-vowel and a dichotic rhyme (fusion) test. Both test procedures were administered to 20 young adults in three different listening conditions (free recall, attention directed to the left ear, and attention directed to the right ear). Results from this study supported the hypothesis that dichotic rhyme tests are resistant to alterations in the laterality of attention and have implications for the development of test paradigms that can be used to segregate attention from pure auditory deficits in the clinical domain.

Development of a 500-Hz masking-level difference protocol for clinic use.

The purpose of this series of experiments was to develop a simple, 500-Hz masking-level difference (MLD) protocol that could be implemented easily in the clinic to assess auditory perceptual abilities using an audio compact disc. Five, 300-ms tones with 250-ms intertone intervals were embedded in 3-s bursts of 200-800 Hz noise presented at 42.2-dB pressure-spectrum level with 4-5 s interstimulus intervals. The homophasic and antiphasic conditions were interleaved with the signal-to-noise ratios decreasing in 2-dB steps. A single-interval, "yes/no" response task was used. Three experiments were performed on 24-28 listeners with normal hearing. The mean SoNo thresholds (58.1- to 59.5-dB SPL) and the mean SpiNo thresholds (45.1- to 46.0-dB SPL) produced approximately 13-dB MLDs. Experiment 3 included a SoNpi condition that had a mean threshold of 48.8-dB SPL and a 10.0-dB MLD. The mean test, retest of the SoNo and SpiNo thresholds on 15 listeners was < 0.5 dB. Over the three experiments, 95% of the listeners had SpiNo MLDs that were > or = 10 dB.

Interaural asymmetries revealed by dichotic listening tests in normal and dyslexic children.

Normal and dyslexic right-handed children were assessed with three dichotic listening tests, the Dichotic Digits test, the Competing Words subtest of the SCAN, and the Dichotic Consonant-Vowel test. Performance was measured as both number and percentage of correct responses in the right and left ears. Laterality was defined as a simple difference in percentage between the two ears. Differences across the tests were revealed for all children, with the greatest differences occurring for left-ear responses. Only one dichotic listening test, Competing Words from the SCAN, produced a consistent right-ear advantage across all of the children tested. Between groups of children, differences in performance and in laterality were demonstrated. Using a criterion of poorer than 76 percent correct for the left ear, the Competing Words subtest of the SCAN identified 7 of the 10 dyslexic children as abnormal, with no false alarms in the control group.