Behavioral profiles associated with auditory processing disorder and specific language impairment

PurposeTo describe and compare behavioral profiles associated with auditory processing disorder (APD) and specific language impairment (SLI) in school-age children.MethodThe participants in this cross-sectional observational study were 64 children (mean age 10.1 years) recruited through clinician referrals. Thirty-five participants had a clinical diagnosis of APD and 29 were receiving services for language impairment. Participants completed 18 behavioral measures of spoken language, auditory processing, reading, memory, and motor speed. Responses were used to classify children as affected/not affected with APD, and affected/not affected with SLI. Comparisons were made between children with and without an APD diagnosis, and between children assigned to the APD/not APD and SLI/not SLI groups. Agreement between clinical status and test-based classifications is also reported.ResultsThere were no group mean differences between children with and without a clinical diagnosis of APD. Group mean differences on Cube Design and reading fluency were observed for children classified as APD/not APD; and group mean differences on nonword repetition, spatial working memory, and two auditory processing tests were observed for children classified as SLI/not SLI.ConclusionsThe behavioral profiles of children with APD and SLI were very similar. Although group mean differences were found, they were difficult to interpret in terms of current theories.Learning outcomes: The reader will be able to: (1) describe similarities and differences found between children with SLI and children with APD and (2) discuss assessment problems posed by overlapping behavioral characteristics of SLI and APD.     

The relation between working memory capacity and auditory lateralization in children with auditory processing disorders

ObjectiveAuditory processing disorder (APD) describes a complex and heterogeneous disorder characterized by poor speech perception, especially in noisy environments. APD may be responsible for a range of sensory processing deficits associated with learning difficulties. There is no general consensus about the nature of APD and how the disorder should be assessed or managed. This study assessed the effect of cognition abilities (working memory capacity) on sound lateralization in children with auditory processing disorders, in order to determine how “auditory cognition” interacts with APD.MethodsThe participants in this cross-sectional comparative study were 20 typically developing and 17 children with a diagnosed auditory processing disorder (9–11 years old). Sound lateralization abilities investigated using inter-aural time (ITD) differences and inter-aural intensity (IID) differences with two stimuli (high pass and low pass noise) in nine perceived positions. Working memory capacity was evaluated using the non-word repetition, and forward and backward digits span tasks. Linear regression was employed to measure the degree of association between working memory capacity and localization tests between the two groups.ResultsChildren in the APD group had consistently lower scores than typically developing subjects in lateralization and working memory capacity measures. The results showed working memory capacity had significantly negative correlation with ITD errors especially with high pass noise stimulus but not with IID errors in APD children.ConclusionsThe study highlights the impact of working memory capacity on auditory lateralization. The finding of this research indicates that the extent to which working memory influences auditory processing depend on the type of auditory processing and the nature of stimulus/listening situation.     

Assessment of the efferent auditory system in children with suspected auditory processing disorder: the Middle ear muscle reflex and contralateral inhibition of OAEs

Objective: To determine whether children aged 7 to 12?years with listening difficulties show objective evidence for efferent auditory function based on measurements of medial olivo-cochlear and middle ear muscle reflexes.

Design: Click-evoked otoacoustic emissions recorded with and without contralateral broadband noise and ipsilateral and contralateral tonal (1000, 2000?Hz) middle ear muscle reflex thresholds were examined.

Study sample: 29 children diagnosed with suspected auditory processing disorder (APD) and a control group of 34 typically developing children participated in this study.

Results: Children with suspected APD had poorer performance on auditory processing tests than the control group. Middle ear muscle reflex thresholds were significantly higher at 2000?Hz in the suspected APD group for contralateral stimulation. MOC inhibition effects did not differ between APD and control groups.

Conclusions: This research supports earlier studies showing altered acoustic reflexes in children with APD. No group differences were found for the MOC reflex measures, consistent with some earlier studies in children with APD.     

Auditory Processing Disorders with and without Central Auditory Discrimination Deficits

Auditory processing disorder (APD) is defined as a processing deficit in the auditory modality and spans multiple processes. To date, APD diagnosis is mostly based on the utilization of speech material. Adequate nonspeech tests that allow differentiation between an actual central hearing disorder and related disorders such as specific language impairments are still not adequately available. In the present study, 84 children between 6 and 17 years of age (clinical group), referred to three audiological centers for APD diagnosis, were evaluated with standard audiological tests and additional auditory discrimination tests. Latter tests assessed the processing of basic acoustic features at two different stages of the ascending central auditory system: (1) auditory brainstem processing was evaluated by quantifying interaural frequency, level, and signal duration discrimination (interaural tests). (2) Diencephalic/telencephalic processing was assessed by varying the same acoustic parameters (plus signals with sinusoidal amplitude modulation), but presenting the test signals in conjunction with noise pulses to the contralateral ear (dichotic_signal/noise tests). Data of children in the clinical group were referenced to normative data obtained from more than 300 normally developing healthy school children. The results in the audiological and the discrimination tests diverged widely. Of the 39 children that were diagnosed with APD in the audiological clinic, 30 had deficits in auditory performance. Even more alarming was the fact that of the 45 children with a negative APD diagnosis, 32 showed clear signs of a central hearing deficit. Based on these results, we suggest revising current diagnostic procedure to evaluate APD in order to more clearly differentiate between central auditory processing deficits and higher-order (cognitive and/or language) processing deficits.     

Assessment of auditory processing disorder in children using an adaptive filtered speech test

Abstract

Objective: One type of test commonly used to assess auditory processing disorder (APD) is the ‘filtered words test’ (FWT), in which a monaural, low-redundancy speech sample is distorted by using filtering to modify its frequency content. One limitation of the various existing FWTs is that they are performed using a constant level of low-pass filtering, making them prone to ceiling and floor effects that compromise their efficiency and accuracy. A recently developed computer-based test, the University of Canterbury Adaptive Speech Test- Filtered Words (UCAST-FW), uses an adaptive procedure intended to improve the efficiency and sensitivity of the test over its constant-level counterparts. Design: The UCAST-FW was administered to school-aged children to investigate the ability of the test to distinguish between children with and without APD. Study sample: Fifteen children aged 7–13 diagnosed with APD, and an aged-matched control group of 10 children with no history of listening difficulties. Results: Data obtained demonstrates a significant difference between the UCAST-FW results obtained by children with APD and those with normal auditory processing. Conclusions: These findings provide evidence that the UCAST-FW may discriminate between children with and without APD with greater sensitivity than its constant-level counterparts.     

Central auditory processing disorder (CAPD) in children with specific language impairment (SLI). Central auditory tests

The aim of this project is to use central auditory tests for diagnosis of central auditory processing disorder (CAPD) in children with specific language impairment (SLI), in order to confirm relationship between speech-language impairment and central auditory processing. We attempted to establish special dichotic binaural tests in Czech language modified for younger children. Tests are based on behavioral audiometry using dichotic listening (different auditory stimuli that presented to each ear simultaneously). The experimental tasks consisted of three auditory measures (test 1-3)-dichotic listening of two-syllable words presented like binaural interaction tests. Children with SLI are unable to create simple sentences from two words that are heard separately but simultaneously. Results in our group of 90 pre-school children (6-7 years old) confirmed integration deficit and problems with quality of short-term memory. Average rate of success of children with specific language impairment was 56% in test 1, 64% in test 2 and 63% in test 3. Results of control group: 92% in test 1, 93% in test 2 and 92% in test 3 (p<0.001). Our results indicate the relationship between disorders of speech-language perception and central auditory processing disorders.     

Auditory Processing Disorders in children suspected of Learning Disabilities—A need for screening?

Aim

The current study aims to assess: (a) the prevalence of auditory processing in a population of children reporting learning difficulties, (b) the correlation of APD diagnosis with age, the intelligence coefficient (IQ) and with the presence of a specific learning disability such as dyslexia and (c) to evaluate the reliability of each auditory processing test used in this study in identifying APD.

Method

We evaluated one hundred and twenty-seven consecutive children referred to the academic tertiary LD Clinic of the Psychiatric Department by means of a psychoacoustic mainly non-verbal test battery.

Results

APD was found to be present in 43.3% and co-existing with developmental dyslexia in 25% of cases. The diagnosis of APD correlated with age in that children with APD were younger by 2 years than those without a diagnosis of APD. The diagnosis of APD did not correlate with IQ or with the diagnosis of dyslexia.

Interpretation

High prevalence of APD in the targeted group of children suspected of Learning Disabilities sets the grounds for a possible benefit in screening for the disorder.     

Contralateral suppression of otoacoustic emissions in a clinical sample of children with auditory processing disorder

Objective: The suppression of evoked otoacoustic emissions (EOAE) may serve as a clinical tool to evaluate the medial olivocochlear (MOC) reflex, which is thought to aid speech discrimination (particularly in noise) by selectively inhibiting cochlear amplification. The present study aimed to determine if contralateral transient evoked otoacoustic emission (TEOAE) suppression was present in a clinical sample of children with listening difficulties with and without auditory processing disorder (APD).

Design: A three-group, repeated measure design was used.

Study sample: Forty three children aged 8–14?years underwent an auditory processing assessment and were divided into three groups: children with reported listening difficulties with APD, children with reported listening difficulties without APD, and children with normal hearing. APD was defined as per British Society of Audiology.

Results: TEOAE suppression was present in all three participant groups. No significant group, age or ear effects were observed for TEOAE suppression in dB or as a normalised index.

Conclusion: Contralateral TEOAE suppression method could not be used as a clinical tool to identify APD in this study’s participating children and did not support the hypothesised link between reduced MOC function and general listening difficulties in background noise in children with or without APD.     

The Danish test battery for auditory processing disorder evaluated with patient and control data

Abstract

Objective: This study evaluates the Danish test battery for auditory processing disorder (APD). The battery consists of four behavioural tests, two speech and two non-speech stimuli tests. The evaluation includes determination of: (1) new cut-off values (pass-fail criteria), (2) the sensitivity and the specificity of the entire test battery and (3) the failure rate of different test combinations.

Design: For each test in the battery, cut-off values were determined using the weighted Youden index. Applying the newly derived cut-off values, the distribution of failing specific test combinations was determined.

Study sample: A group of 112 children diagnosed with APD (57 boys, 55 girls, aged 6–16?years) and a control group containing 158 children without auditory problems (75 boys, 83 girls, aged 6–16?years).

Results: Cut-off values for different weights of the sensitivity and the specificity have been determined. Using the criterion that at least two tests have to be failed for APD to be suspected, the sensitivity and the specificity of the entire test battery were 95.3% and 91.6%, respectively. Some test combinations were found to have higher failure rates than others.

Conclusions: Due to the high sensitivity and specificity the test battery has good predictive value in APD assessment.     

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.     

Auditory processing in children with normal and disordered speech

Phonological speech disorders are characterized by abnormal development towards the adult target pattern; its etiology is unknown. It is thought the this condition results from auditory processing disorders involving the abilities required for human beings to understand what is heard.AimTo investigate the relationship between auditory processing and the acquisition of disordered or normal speech, drawing comparisons between these profiles.Material and MethodA prospective, contemporary, cross-sectional study comprising a sample of 44 subjects aged 5 to 7 years; two groups were formed: a study group (SG) comprising children with disordered speech acquisition, and a control group (CG) consisting of children with normal speech acquisition. A simplified evaluation of auditory processing was undertaken: the PSI test in Portuguese; the speech-in-noise test; the binaural fusion test; the dichotic digit test; and the staggered spondaic word test (SSW).ResultsThere was a statistically significant difference between the two groups; the SG scored worse than the CG in all the tests. The PSI test only - with a 100% success rate - scored equally in both groups.ConclusionAuditory processing may affect speech development.     

The contribution of processing impairments to SLI: Insights from attention-deficit/hyperactivity disorder

Slowed speed of processing and impaired rapid temporal processing (RTP) have been proposed to underlie specific language impairment (SLI), but it is not clear that these dysfunctions are unique to SLI. We considered the contribution of attention-deficit/hyperactivity disorder (ADHD), which frequently co-occurs with language impairments, to performances on processing tasks. School-aged children who had SLI without concurrent ADHD (n = 14), ADHD without concurrent SLI (n = 14), and typical development (TD, n = 28) performed two nonverbal speeded tasks and one auditory RTP task. RTP impairments were found in many children with SLI and ADHD, and some children with TD. Children with ADHD demonstrated slower processing speed than children with SLI or TD. Overall, findings questioned the uniqueness of these processing dysfunctions to language impairments and the validity of the behavioural paradigms traditionally used to estimate processing dysfunctions. Accounts of SLI should be further scrutinized by considering the influence of other disorders.Learning outcomes: Readers will (1) become familiar with areas of overlap between SLI and ADHD, (2) understand some of the confounds associated with behavioural measures of processing speed in children, and (3) recognize the value in testing models of language disorders by including participants with other types of disorders.     

Auditory event-related potentials and function of the medial olivocochlear efferent system in children with auditory processing disorders

Objective: The objectives were to investigate the function of central auditory pathways and of the medial efferent olivocochlear system (MOCS).

Design: Event-related potentials (ERP) were recorded following the delivery of the stimulus /da/ in quiet and in ipsilateral, contralateral, and binaural noise conditions and correlated to the results of the auditory processing disorders (APD) diagnostic test battery. MOCS function was investigated by adding ipsilateral, contralateral, and binaural noise to transient evoked otoacoustic emission recordings. Auditory brainstem responses and pure tone audiogram were also evaluated.

Study Sample: Nineteen children (7 to 12?years old) with APD were compared with 24 age-matched controls.

Results: Otoacoustic emissions and ABR characteristics did not differ between groups, whereas ERP latencies were significantly longer and of higher amplitudes in APD children than in controls, in both quiet and noise conditions. The MOCS suppression was higher in APD children.

Conclusions: Findings indicate that children with APD present with neural deficiencies in both challenging and nonchallenging environments with an increase in the timing of several central auditory processes correlated to their behavioural performances. Meanwhile, their modulation of the auditory periphery under noisy conditions differs from control children with higher suppression.     

Association between top-down skills and auditory processing tests

Today, we are questioning how top-down skills may interfere with performance on auditory processing tests.ObjectiveTo investigate the existence of a possible association between memory, attention and language skills in auditory processing tests in “normal” development children.MethodTwenty children (ages 7 to 9 years), without complaints related to verbal and/or written language skills; without overt neurological or psychological involvement or delayed psychomotor development. We employed Hearing and auditory Processing Assessment tests in addition to psychophysical tests (visual and auditory attention tests; memory tests for digits and syllables and phonological awareness tests).Resultsthere was a “very strong” correlation between Frequency Pattern and Memory for Digits Tests; a “strong” correlations between SSW (LE) test and Memory for Syllables, and SSW (LE) test and phonemic tasks.Conclusionthe Frequency Pattern Test showed a strong correlation with the phonological working memory skill; just as the SSW had with language and memory skills for syllables. It is noteworthy the difficult to clinically interpret the results of each auditory processing test alone, since these may be dependent on skills not necessarily related to the auditory modality, such as memory and language.     

Sequenzielle Informationsverarbeitung bei Kindern mit und ohne auditive Verarbeitungs- und Wahrnehmungsstörung

Background

It is a controversial issue whether sequential processing in children with auditory processing disorders (APD) is a unimodal auditory impairment.

Patients and methods

Normal achieving controls (n=12; mean age: 101.1 months; SD 20.3) and children referred to clinical facilities for assessment including children with monosymptomatic APD (n=25; mean age: 90.8 months; SD 9.8), children with developmental language disorder (DLD]) + APD (n=11; mean age: 89.5 months; SD 14.9), children with dyslexia + APD (n=10; mean age: 113.8 months; SD 17.1) were compared using the subtest digit recall of the German version of the K-ABC (Melchers & Preuß 2001) and the K-ABC subtest hand movements in the visual modality.

Results

On average all groups tended to perform alike in visual sequential processing and memory (T-score>50). Normal controls (non-APD) showed on average the best test performance (T-score 57.4; SD 10.5), but the mean performance did not differ significantly from children with APD. All groups also presented on average normal test performance in the auditory modality however, children of the clinical groups were below the age mean (DLD + APD: T-W 43.1; SD 6.8; monosymptomatic APD: T-W 45.8; SD 9.8; dyslexia + APD: 46.7; SD5.8). Children with DLD + APD and those with monosymptomatic APD exhibited a significantly lower but not poor performance in auditory processing of sequences compared to their performance in visual sequential processing. The results of auditory and visual processing of sequences were significantly correlated in the clinical groups DLD + APD (0.58) and monosymptomatic APD (0.34), but not in the smallest group dyslexia + APD (0.48) and in normal achieving controls (0.32).

Conclusion

On the basis of the results of the present study it may be concluded that a normal test performance on visual measure does not exclude a bimodal or pansensory seriation disorder in children with APD. It does, however, indicate the existence of a primary auditory sequential processing deficit, because at least the processing of phonological and visual stimuli was not separately carried out in children with DLD + APD.     

Electrophysiological characteristics in children with listening difficulties,with or without auditory processing disorder

Abstract

Objective: To determine if the auditory middle latency responses (AMLR), auditory late latency response (ALLR) and auditory P300 were sensitive to auditory processing disorder (APD) and listening difficulties in children, and further to elucidate mechanisms regarding level of neurobiological problems in the central auditory nervous system.

Design: Three-group, repeated measure design.

Study sample: Forty-six children aged 8–14 years were divided into three groups: children with reported listening difficulties fulfilling APD diagnostic criteria, children with reported listening difficulties not fulfilling APD diagnostic criteria and normally hearing children.

Results: AMLR Na latency and P300 latency and amplitude were sensitive to listening difficulties. No other auditory evoked potential (AEP) measures were sensitive to listening difficulties, and no AEP measures were sensitive to APD only. Moderate correlations were observed between P300 latency and amplitude and the behavioural AP measures of competing words, frequency patterns, duration patterns and dichotic digits.

Conclusions: Impaired thalamo-cortical (bottom up) and neurocognitive function (top-down) may contribute to difficulties discriminating speech and non-speech sounds. Cognitive processes involved in conscious recognition, attention and discrimination of the acoustic characteristics of the stimuli could contribute to listening difficulties in general, and to APD in particular.     

A systematic review of electrophysiological outcomes following auditory training in school-age children with auditory processing deficits

Abstract

Objective: To systematically review the peer-reviewed literature on electrophysiological outcomes following auditory training (AT) in school-age children with (central) auditory processing disorder ([C]APD). Design: A systematic review. Study sample: Searches of 16 electronic databases yielded four studies involving school-aged children whose auditory processing deficits had been confirmed in a manner consistent with and and compared to a treated and/or an untreated control group before and after AT. A further three studies were identified with one lacking a control group and two measuring auditory processing in a manner not consistent with and . Results: There is limited evidence that AT leads to measurable electrophysiological changes in children with auditory processing deficits. Conclusion: The evidence base is too small and weak to provide clear guidance on the use of electrophysiological outcomes as a measure of AT outcomes in children with auditory processing problems. The currently limited data can only be used to suggest that click-evoked AMLR and tone-burst evoked auditory P300 might be more likely to detect such outcomes in children diagnosed with (C)APD, and that speech-evoked ALLR might be more likely to detect phonological processing changes in children without a specific diagnosis of (C)APD.     

Binaural sensitivity to temporal fine structure and lateralization ability in children with suspected (central) auditory processing disorder

Objective

Previous studies have shown that a subgroup of children with suspected (central) auditory processing disorder (SusCAPD) have insufficient ability to use binaural cues to benefit from spatial processing. Thus, they experience considerable listening difficulties in challenging auditory environments, such as classrooms. Some researchers have also indicated the probable role of binaural temporal fine structure (TFS) in the perceptual segregation of target signal from noise and hence in speech perception in noise. Therefore, in the present study, in order to further investigate the underlying reason for listening problems against background noise in this group of children, their performance was measured using binaural TFS sensitivity test (TFS-LF) as well as behavioral auditory lateralization in noise test, both of which are based on binaural temporal cues processing.

Auditory processing disorders: Relationship to cognitive processes and underlying auditory neural integrity

Background

Auditory processing disorder (APD) in children has been reported and discussed in the clinical and research literature for many years yet there remains poor agreement on diagnostic criteria, the relationship between APD and cognitive skills, and the importance of assessing underlying neural integrity.

Purpose

The present study used a repeated measures design to examine the relationship between a clinical APD diagnosis achieved with behavioral tests used in many clinics, cognitive abilities measured with standardized tests of intelligence, academic achievement, language, phonology, memory and attention and measures of auditory neural integrity as measured with acoustic reflex thresholds and auditory brainstem responses.

Method

Participants were 63 children, 7–17 years of age, who reported listening difficulties in spite of normal hearing thresholds. Parents/guardians completed surveys about the child's auditory and attention behavior while children completed an audiologic examination that included 5 behavioral tests of auditory processing ability. Standardized tests that examined intelligence, academic achievement, language, phonology, memory and attention, and objective tests auditory function included crossed and uncrossed acoustic reflex thresholds and auditory brainstem responses (ABR) were also administered to each child.

Results

Forty of the children received an APD diagnosis based on the 5 behavioral tests and 23 did not. The groups of children performed similarly on intelligence measures but the children with an APD diagnosis tended to perform more poorly on other cognitive measures. Auditory brainstem responses and acoustic reflex thresholds were often abnormal in both groups of children.

Summary

Results of this study suggest that a purely behavioral test battery may be insufficient to accurately identify all children with auditory processing disorders. Physiologic test measures, including acoustic reflex and auditory brainstem response tests, are important indicators of auditory function and may be the only indication of a problem. The results also suggest that performance on behavioral APD tests may be strongly influenced by the child's language levels.