Auditory Processing Disorder Children Research Articles

Auditory Discrimination—A Missing Piece of Speech and Language Development: A Study on 6–9-Year-Old Children with Auditory Processing Disorder

Auditory discrimination, the hearing ability crucial for speech and language development, allowing one to perceive changes in volume, duration and frequency of sounds, was assessed for 366 participants with normal peripheral hearing: 220 participants with auditory processing disorders (APD) and 146 typically developing (TD) children, all aged 6-9 years. Discrimination of speech was tested with nonsense words using the phoneme discrimination test (PDT), while pure tones-with the frequency pattern test (FPT). The obtained results were statistically analyzed and correlated. The median of the FPT results obtained by participants with APD was more than twice lower than those of TD (20% vs. 50%; p < 0.05), similarly in the PDT (21 vs. 24; p < 0.05). The FPT results of 9-year-old APD participants were worse than the results of TD 6-year-olds (30% vs. 40%; p < 0.05), indicating that the significant FPT deficit strongly suggests APD. The process of auditory discrimination development does not complete with the acquisition of phonemes but continues during school age. Physiological phonemes discrimination is not yet equalized among 9-year-olds. Nonsense word tests allow for reliable testing of phoneme discrimination. APD children require testing with PDT and FPT because both test results allow for developing individual therapeutic programs.

Auditory Spectro-Temporal Modulation Training in Children With Auditory Processing Disorder

Objectives: Auditory processing disorder (APD) is due to the deficits in perceptual processing of acoustic information in the auditory system, characterized by poor speech perception of noise, regardless of normal hearing. The variability in speech function of APD children can be partly explained by changes in the encoding of spectro-temporal modulations (STMs) which have been overlooked, despite their significance. Given that enhancing STM sensitivity and its processing can be an appropriate way to improve the listener’s ability to retrieve and integrate speech segments covered by noise, we decided to evaluate the effects of STM-based auditory training on speech perception in noise and the reliability of this training in children with APD. Methods: Thirty-five children with APD (8-12 years old) were randomly divided into the training (n=17) and control groups (n=18) to evaluate the effectiveness and reliability of STM training on speech in noise perception. The intervention group was trained to detect STM by 120 trials every day for ten days. The STM detection thresholds and speech perception in noise were evaluated before and immediately after the finalization of formal training sessions in both groups. To address the training reliability, the tests were repeated one month after practice in the training group. Results: Following the completion of STM auditory training, the trained APD children improved notably in STM detection tasks and speech in noise tests (P&lt;0.05). The post-training progress of STM detection thresholds and consonant-vowel in the noise test was preserved for one month after training (P&gt;0.05), but the word in the noise test, especially in the right ear, was not retained (P&lt;0.05). Discussion: Auditory spectro-temporal modulation training can lead to better processing of STM modulation. Its effects can be generalized to higher-order processing, such as speech perception in noise. Auditory training based on STM processing enhancement can play an essential role in improving speech comprehension in the noise abilities of children with APD.

Altered brain network topology in children with auditory processing disorder: A resting-state multi-echo fMRI study

Children with auditory processing disorder (APD) experience hearing difficulties, particularly in the presence of competing sounds, despite having normal audiograms. There is considerable debate on whether APD symptoms originate from bottom-up (e.g., auditory sensory processing) and/or top-down processing (e.g., cognitive, language, memory). A related issue is that little is known about whether functional brain network topology is altered in APD. Therefore, we used resting-state functional magnetic resonance imaging data to investigate the functional brain network organization of 57 children from 8 to 14 years old, diagnosed with APD (n = 28) and without hearing difficulties (healthy control, HC; n = 29). We applied complex network analysis using graph theory to assess the whole-brain integration and segregation of functional networks and brain hub architecture. Our results showed children with APD and HC have similar global network properties –i.e., an average of all brain regions– and modular organization. Still, the APD group showed different hub architecture in default mode-ventral attention, somatomotor and frontoparietal-dorsal attention modules. At the nodal level –i.e., single-brain regions–, we observed decreased participation coefficient (PC – a measure quantifying the diversity of between-network connectivity) in auditory cortical regions in APD, including bilateral superior temporal gyrus and left middle temporal gyrus. Beyond auditory regions, PC was also decreased in APD in bilateral posterior temporo-occipital cortices, left intraparietal sulcus, and right posterior insular cortex. Correlation analysis suggested a positive association between PC in the left parahippocampal gyrus and the listening-in-spatialized-noise -sentences task where APD children were engaged in auditory perception. In conclusion, our findings provide evidence of altered brain network organization in children with APD, specific to auditory networks, and shed new light on the neural systems underlying children's listening difficulties.

Self-perceived stress and the personality of mothers of children with central auditory processing disorders – Differences from mothers of typically developing children

PurposeTo investigate the relationship between self-perceived global stress and the personality traits of mothers of children with central auditory processing disorders (APD), and make a comparison with mothers of typically developing (TD) children. Design and methodsA cross-sectional study using two questionnaires – the Perceived Stress Scale (PSS-10) and the Short Big Five Markers (IPIP-BFM-20) – to assess five personality dimensions: extraversion, agreeableness, conscientiousness, emotional stability, and intellect/imagination. The study material included 187 mothers, of whom 108 were mothers of children with APD. The average age of the children with APD was 10 years. ResultsThe average level of global stress was similar in mothers of children with APD and mothers of TD children. Mothers of APD children had significantly lower scores for personality dimensions such as: emotional stability, conscientiousness, and intellect/imagination. Increased perceived stress level in mothers of children with APD was inversely correlated with extraversion, conscientiousness, and emotional stability. However, for both groups of mothers, the only significant predictor of global stress level was emotional stability. ConclusionMothers of children with APD, despite having similar global stress levels to other mothers, were different in terms of three personality dimensions, and these, especially lowered emotional stability, may play a negative role in coping with global self-perceived stress. Practice implicationsThe results of this study might be helpful in parental support interventions, including psychological therapy and counselling, and also in parental implementation interventions aimed at mothers of children with APD, especially those mothers who have high global stress and/or low emotional stability.

Auditory processing disorder in children: the value of a multidisciplinary assessment.

Auditory processing disorder (APD) may affect 0.2-5% of the paediatric population. The diagnosis of APD remains difficult because of polymorphic symptoms possibly entangled with other difficulties. The purpose of this study was to evaluate a new multi-disciplinary assessment in the French language. The battery of tests was composed of: (a) APD targeted speech assessment: speech perception in noise, a dichotic test, temporal processing tests (patterns); (b) Psychometric assessment: sustained auditory attention, sustained visual attention, evaluation of cognitive functions; (c) phonemic identification and discrimination; (d) ENT examination, tonal and vocal audiometry and ABR recordings. The diagnosis was made if two of the targeted speech tests were 2 standard deviations (SDs) below the mean or if only one of the tests was 3 SDs below. The auditory attention tests, as well as the phonemic identification and discrimination tests were complementary to the diagnostic battery. However, they did not allow for the diagnosis of APD. 50 children suspected of APD benefited from this protocol, and 12 were excluded from the study. A diagnosis of APD was confirmed in 17 children (45%). 59% of the patients had associated disorders. The most effective tests for diagnosing APD were dichotic testing (p = 0.001) and pattern recognition (frequency, p = 0.001). The sustained auditory attention test (p = 0.01) and the phonemic identification and discrimination test reinforced the diagnosis of APD. It seems important to evaluate children suspected of APD with a multi-disciplinary protocol. It makes it possible to diagnose APD children, but also to identify attentional difficulties and cognitive disorders that may be associated.

Auditory processing, co-morbidities, and parental report of sleep disturbance in children with auditory processing disorder (APD)

ObjectivesTo evaluate the prevalence of sleep disturbance and its relationship with auditory processing (AP) and co-morbidities in children diagnosed with auditory processing disorder (APD). MethodsData from 109 children (Males = 59, Females = 50) with mean non-verbal intelligence quotient (NVIQ) of 89.44 (SD:18.16), aged between 6 and 16 years (mean: 10 years 7 months; SD: 2 years 9 months) with a diagnosis of APD were analysed. Participants performed ≤1.33 SD below the mean in two or more out of five SCAN-3 diagnostic APD tests that included ‘Filtered Words’ (FW), ‘Auditory Figure Ground 0 dB’ (AFG0), ‘Competing Words-Directed Ear’ (CW-DE), ‘Competing Sentences’ (CS) and ‘Time Compressed Sentences’ (TCS). Concern about sleep in addition to other symptoms and medical history were documented from structured parental history sheet which forms part of the routine APD assessment. Language impairment (LI), attention-deficit-hyperactivity-disorder (ADHD) and oppositional defiant disorder (ODD), and anxiety were evaluated using the ‘Children's Communication Checklist-2’ (CCC-2), ‘Swanson Nolan and Pelham rating scale’ (SNAP-IV) and ‘Anxiety Scale for Children-Autism Spectrum Disorder’ (ASC-ASD) respectively. ResultsSixty children had sleep disturbance, a prevalence of 55% (95% CI 45.2%–64.6%). The two groups of APD children, with (n = 49) and without sleep (n = 60) disturbance, did not vary in their auditory processing abilities. The sleep disturbed group had significant issues with pragmatic language impairment, hyperactivity/impulsivity, oppositional defiant symptoms and anxiety compared to the group without sleep disturbance when they were analysed separately. After the variables were considered in step wise fashion in binary logistic regression analyses, only pragmatic language impairment and anxiety predicted sleep disturbance (p < .01). ConclusionIn APD the prevalence of sleep disturbance is high, justifying screening within a transdisciplinary APD assessment protocol. Sleep disturbance in APD is predicted by pragmatic language impairment and anxiety, but not by ADHD symptoms or ODD.

Absence of Rhythm Benefit on Speech in Noise Recognition in Children Diagnosed With Auditory Processing Disorder.

Auditory processing disorder (APD) is a specific deficit in the processing of auditory information along the central auditory nervous system. It is characterized mainly by deficits in speech in noise recognition. APD children may also present with deficits in processing of auditory rhythm. Rhythmic neural entrainment is commonly present in perception of both speech and music, while auditory rhythmic priming of speech in noise has been known to enhance recognition in typical children. Here, we test the hypothesis that the effect of rhythmic priming is compromised in APD children, and further assessed for correlations with verbal and non-verbal auditory processing and cognition. Forty APD children and 33 neurotypical ones were assessed through (a) WRRC, a test measuring the effects of rhythmic priming on speech in noise recognition, (b) a battery of auditory processing tests, commonly used in APD diagnosis, and (c) two cognitive tests, assessing working memory and auditory attention respectively. Findings revealed that (a) the effect of rhythmic priming on speech in noise recognition is absent in APD children, (b) it is linked to non-verbal auditory processing, and (c) it is only weakly dependent on cognition. We discuss these findings in light of Dynamic Attention Theory, neural entrainment and neural oscillations and suggest that these functions may be compromised in APD children. Further research is needed (a) to explore the nature of the mechanics of rhythmic priming on speech in noise perception and why the effect is absent in APD children, (b) which other mechanisms related to both rhythm and language are also affected in this population, and (c) whether music/rhythm training can restore deficits in rhythm effects.

Spectro-temporal modulation detection and its relation to speech perception in children with auditory processing disorder

ObjectivesPoor speech perception in noise is one of the most common complaints reported for children with auditory processing disorder (APD). APD is defined as a deficit in perceptual processing of acoustic information in the auditory system in which decreased spectro-temporal resolution may also contribute. Since the recognition of spoken message in the context of other sounds, is based on the processing of auditory spectro-temporal modulations, the assessment of spectro-temporal modulations sensitivity can evaluate the listener's ability to retrieve and integrate speech segments covered by noise. Therefore, the purpose of this study was to examine spectro-temporal modulation (STM) detection and its relation to speech perception in children with APD and to compare the results with aged-matched normally developed children. Methods35 children with APD and 32 normal hearing children (8–12 years old) were enrolled. In order to examine STM detection performance, six different STM stimulus conditions were employed using three different temporal modulation rates (4, 12 and 32 Hz) and two different spectral modulation densities (0.5 and 2.0 cycles/octave). Initially, the STM detection thresholds at these six STM stimulus conditions were measured in both groups and the results were compared. Thereafter, the relation between STM detection thresholds and speech perception tests, including consonant-vowel in noise and word in noise tests were assessed. ResultsThe STM sensitivity was poorer than normal for APD children at all STM stimulus conditions. Children with APD displayed significantly poorer STM detection thresholds than those of normally developed children (p < 0.05). Significant correlations were found between STM detection thresholds and speech perception in noise in both groups (p < 0.05). ConclusionThe results suggest that the altered encoding of spectro-temporal acoustic cues in the auditory nervous system may be one of the underlying factors of reduced STM detection performance in children with APD. The present study may suggest that poor ability to extract STM cues in children with APD, can be an underlying factor for their listening problems in noise and poor speech perception in challenging situations.

Deficits in Auditory Rhythm Perception in Children With Auditory Processing Disorder Are Unrelated to Attention.

Auditory processing disorder (APD) is defined as a specific deficit in the processing of auditory information along the central auditory nervous system, including bottom-up and top-down neural connectivity. Even though music comprises a big part of audition, testing music perception in APD population has not yet gained wide attention in research. This work tests the hypothesis that deficits in rhythm perception occur in a group of subjects with APD. The primary focus of this study is to measure perception of a simple auditory rhythm, i.e., short isochronous sequences of beats, in APD children and to compare their performance to age-matched normal controls. The secondary question is to study the relationship between cognition and auditory processing of rhythm perception. We tested 39 APD children and 25 control children aged between 6 and 12 years via (a) clinical APD tests, including a monaural speech in noise test, (b) isochrony task, a test measuring the detection of small deviations from perfect isochrony in a isochronous beats sequence, and (c) two cognitive tests (auditory memory and auditory attention). APD children scored worse in isochrony task compared to the age-matched control group. In the APD group, neither measure of cognition (attention nor memory) correlated with performance in isochrony task. Left (but not right) speech in noise performance correlated with performance in isochrony task. In the control group a large correlation (r = −0.701, p = 0.001) was observed between isochrony task and attention, but not with memory. The results demonstrate a deficit in the perception of regularly timed sequences in APD that is relevant to the perception of speech in noise, a ubiquitous complaint in this condition. Our results suggest (a) the existence of a non-attention related rhythm perception deficit in APD children and (b) differential effects of attention on task performance in normal vs. APD children. The potential beneficial use of music/rhythm training for rehabilitation purposes in APD children would need to be explored.

Spectral ripple discrimination in children with auditory processing disorder

Objective: The purpose of this study was to examine developmental trends in spectral ripple discrimination (SRD) and to compare the performance of typically developing children to children with auditory processing disorder (APD).Study design: Cross-sectional study.Study sample: Fifteen children with APD, as well as 17 typically developing children and 14 adults reporting no listening or academic difficulties participated.Results: Typically developing children showed poor SRD thresholds compared to adults, indicating prolonged maturation of spectral shape recognition. Both typically developing children and APD children showed a maturational trend in SRD, but a General Linear Model fit to their thresholds showed that children with APD displayed SRD thresholds that were significantly poorer than those of typically developing children when controlling for age. This suggests that in APD children, SRD maturation lags behind typically developing children.Conclusion: Poor spectral ripple discrimination may explain some of the listening difficulties experienced by children with APD.

Acoustic Change Complex (ACC) Using Speech and Non-Speech Stimuli in Temporal Auditory Processing Disorders Children

Acoustic Change Complex (ACC) Using Speech and Non-Speech Stimuli in Temporal Auditory Processing Disorders Children

Auditory localization accuracy and auditory spatial discrimination in children with auditory processing disorders

The present study investigated spatial hearing in children aged 6–12 years diagnosed with Auditory Processing Disorders (APD) and compared their results to those of a group of control children matched in age. Sound source localization accuracy was quantified using an absolute localization task and sound source discrimination by measuring the minimum audible angle. Low- and high-frequency noise bursts were presented from eight loudspeaker positions in the left and right hemifields (0°, 30, 60°, and 90° azimuth). Median absolute localization accuracy did not differ between children with APD and control children. However, the intra-individual variability of pointing behavior was higher for children with APD. In contrast, children with APD had significantly higher minimum audible angle thresholds than control children. These findings show that APD impairs sound source discrimination, but does not affect the median relationship between actual and judged sound source locations.

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.

Musical abilities in children with an auditory processing disorder

Objective Difficulties in solving musical tasks are observed in clinical practice in children with an auditory processing disorder (APD). There is a paucity of research on musical ability in children with an APD. Material and Methods To assess musical skills we had 15 children aged 6-11 years with the diagnosis of APD perform a test, and compared them to a control group of 15 children. Results APD children did significantly worse in pitch discrimination, reproduction of rhythm and singing. Correlations between language-based and musical skills in the APD-group were observed. Conclusions Greater attention should be paid to musical skills in APD diagnostics. The positive impact of musical training on language development and cognitive abilities in general has been demonstrated in numerous studies. Musical training should be the focus of further discussion for therapeutic methods of APD in the presence of musical deficits.

Auditory Training Effects on the Listening Skills of Children With Auditory Processing Disorder.

Children with auditory processing disorder (APD) typically present with "listening difficulties,"' including problems understanding speech in noisy environments. The authors examined, in a group of such children, whether a 12-week computer-based auditory training program with speech material improved the perception of speech-in-noise test performance, and functional listening skills as assessed by parental and teacher listening and communication questionnaires. The authors hypothesized that after the intervention, (1) trained children would show greater improvements in speech-in-noise perception than untrained controls; (2) this improvement would correlate with improvements in observer-rated behaviors; and (3) the improvement would be maintained for at least 3 months after the end of training. This was a prospective randomized controlled trial of 39 children with normal nonverbal intelligence, ages 7 to 11 years, all diagnosed with APD. This diagnosis required a normal pure-tone audiogram and deficits in at least two clinical auditory processing tests. The APD children were randomly assigned to (1) a control group that received only the current standard treatment for children diagnosed with APD, employing various listening/educational strategies at school (N = 19); or (2) an intervention group that undertook a 3-month 5-day/week computer-based auditory training program at home, consisting of a wide variety of speech-based listening tasks with competing sounds, in addition to the current standard treatment. All 39 children were assessed for language and cognitive skills at baseline and on three outcome measures at baseline and immediate postintervention. Outcome measures were repeated 3 months postintervention in the intervention group only, to assess the sustainability of treatment effects. The outcome measures were (1) the mean speech reception threshold obtained from the four subtests of the listening in specialized noise test that assesses sentence perception in various configurations of masking speech, and in which the target speakers and test materials were unrelated to the training materials; (2) the Children's Auditory Performance Scale that assesses listening skills, completed by the children's teachers; and (3) the Clinical Evaluation of Language Fundamental-4 pragmatic profile that assesses pragmatic language use, completed by parents. All outcome measures significantly improved at immediate postintervention in the intervention group only, with effect sizes ranging from 0.76 to 1.7. Improvements in speech-in-noise performance correlated with improved scores in the Children's Auditory Performance Scale questionnaire in the trained group only. Baseline language and cognitive assessments did not predict better training outcome. Improvements in speech-in-noise performance were sustained 3 months postintervention. Broad speech-based auditory training led to improved auditory processing skills as reflected in speech-in-noise test performance and in better functional listening in real life. The observed correlation between improved functional listening with improved speech-in-noise perception in the trained group suggests that improved listening was a direct generalization of the auditory training.

Psychosocial Status of Children with Auditory Processing Disorder

Children with hearing loss often exhibit reduced psychosocial status compared to children with normal hearing. It is reasonable to assume that psychosocial function may also be affected in children diagnosed with auditory processing disorder (APD). However, there are no published studies specifically addressing the psychosocial health of children with APD. This investigation examined relationships between APD and psychosocial status, with an aim to examine nonauditory factors that may influence quality of life of children diagnosed with APD. A two-matched group design was employed. Participants and their mothers completed appropriate versions of the Dartmouth Primary Care Cooperative Information Project Charts for Adolescents (COOP-A), the Behavioral Assessment System for Children, Second Edition (BASC-2), and the Social Skills Rating System (SSRS). Participants consisted of 19 children (aged 9.5-17.8 yr; mean = 11.9) diagnosed with APD and 20 gender- and age-matched (mean = 12.8 yr) children with no evidence of APD by history or audiological assessment. Primary caretakers (mothers) of the participants also completed psychosocial questionnaires according to their perception of their participating child's function. Data were collected at a single visit, following APD diagnosis. Data from each questionnaire were analyzed using appropriate statistical methods for two-group comparisons. Analysis of child reports revealed significantly greater psychosocial difficulty in the APD group on subscales of the COOP-A and BASC-2. Increased problems in the APD group were also reported by parents on subscales of the COOP-A, BASC-2, and SSRS. Eta-squared values for all significant findings indicated moderate to large effect sizes, suggesting findings may be generalized to other children in this age group. No between-group differences were found on any subscale for APD children with or without a confirmed or suspected language disorder. We found that children with APD exhibit increased psychosocial difficulty in several areas compared to children without APD.

Contralateral inhibition of distortion product otoacoustic emissions in children with auditory processing disorders

Objective: The purpose of this study was to evaluate changes in distortion product otoacoustic emission (DPOAE) level elicited by contralateral noise in children with normal hearing, and those with auditory processing disorders (APD) whose audiometric thresholds were normal. It was hypothesized that children with APD would demonstrate smaller changes. Design: Levels of DPOAEs were recorded for f2 stimulus tones fixed at 2, 3, and 4 kHz while the f1 tone was ramped around nominal stimulus frequency ratios of f2/f1 = 1.22 and 1.10. Mean and maximum absolute changes resulting from contralateral broadband noise presented at 60 dB SPL were evaluated across the DPOAE frequency bands for each individual and for both groups of subjects. Study sample: Eight normal-hearing children and eight children with APD whose audiometric thresholds were normal participated. Results: There were no significant differences in DPOAE inhibition between normal hearing and APD groups, or previously recorded adult data. Mean absolute changes were typically near 1 dB, except for f2 = 4 kHz and the stimulus frequency ratio 1.22 where inhibition was only 0.5 dB. However, there were individual children in both groups who demonstrated larger DPOAE changes for some stimulus parameters. Conclusions: The inhibition of otoacoustic emissions requires further study in APD children.SumarioObjetivo: El propósito de este estudio fue evaluar los cambios en el nivel de las emisiones otoacústicas por productos de distorsión (DPOAE) generados por ruido contralateral, en niños con audición normal y en aquellos con trastornos de procesamiento auditivo (APD), cuyos umbrales audiométricos era normales. Se planteó la hipótesis que los niños con ADP demostrarían cambios menores. Diseño: Se registraron los niveles de DPOAE para tonos de estímulo f2 fijos a 2, 3 y 4 KHz, mientras que el f1 fue colocado cercano a tasas nominales de frecuencia del estímulo f1/f2 = 1.22 y 1.10. Los cambios medios y máximos absolutos que resultaron del ruido de banda ancha contralateral a 60 dB SPL fueron evaluados en todas las bandas de frecuencias de las DPOAE para cada individuo y para ambos grupos de sujetos. Muestra del Estudio: Participaron ocho niños con audición normal y ocho niños con APD, cuyos umbrales audiométricos eran normales. Resultados: No hubo diferencias significativas en la inhibición de las DPOAE entre los grupos con audición normal y con APD, o con información de adultos previamente registrada. Los cambios medios absolutos estuvieron típicamente cerca de 1 dB, excepto para f2 = 4 kHz, para la tasa de frecuencia del estímulo de 1.22, donde la inhibición fue solo 0.5 dB. Sin embargo, hubo niños individuales en ambos grupos que demostraron cambios mayores en DPOAE para algunos parámetros de estímulo. Conclusiones: La inhibición de las emisiones otoacústicas requiere de más estudio en niños con APD.

Age dependent maturation of NC-ERP

Neutral condition event related potentials (NC-ERP) are not suitable for differentiating between children suffering from auditory processing disorders (APD) alone and APD-children with attention deficit disorder. Other factors beside severity of APD may cause "pathological" NC-ERP. Here we raise the question of whether maturational factors may be responsible for disordered NC-ERP. NC-ERP data from 142 APD children (range 5.4-17.2 years; mean 9.8 years) were analysed. Data were grouped according to age of children (I: <7.11 years n=34; II: 8.0-9.11 years n=46; III: 10.0-11.11 years n=39; IV: >12.0 years n=23). Pathological NC-ERP were found in 82.3% (group I), 56.6% (group II), 46.2% (group III) and 8.8% (group IV). Additional analyses confirmed no correlation with ADHD. Although there is a whole body of evidence that late auditory evoked potential may mature with age, it is not known if NC-ERP are also age dependent. Our results that NC-ERP mature with age are consistent with data for other late auditory evoked potentials. Since normative date of NC-ERP for different age groups are still lacking, NC-ERP results in children should be interpreted very cautiously.

Reduced Medial Olivocochlear Bundle System Function in Children with Auditory Processing Disorders

A common complaint of children with auditory processing disorders (APD) is difficulty in understanding speech in the presence of background noise. Evidence from animal and human studies has suggested that the medial olivocochlear bundle (MOCB) may play a role in hearing in noise. The MOCB function can be evaluated by the suppression effect of the transient evoked otoacoustic emissions (TEOAE) in response to contralateral acoustic stimulation (CAS). The present study was conducted to investigate the suppression effect of TEOAE in APD children. The study groups comprised 15 APD children aged 8–13 years associated with learning disabilities and 15 controls matched for gender and age. The suppression effect of TEOAE was evaluated by comparing the TEOAE levels with and without CAS. A significantly reduced suppression effect of TEOAE was demonstrated in the APD group, when compared to the controls. In addition, higher TEOAE levels were found in the APD group, suggesting inherent reduced MOCB activity on the outer hair cells in APD children. These results imply that some APD children present low activity of the MOCB system, which may indicate a reduced auditory inhibitory function and affect their ability to hear in the presence of background noise.

A Comparison Between Vocal Reaction Time and Word Recognition Measures of Children with APD and Age-Matched Peers Using Auditory Word Discrimination Test

The purpose of this study was to investigate the possibility of improving speech recognition testing sensitivity in children with auditory processing disorders (APD) by incorporating response time measures. A group of children identified in a clinical setting as having APD was compared to an age-matched peer group using a vocal reaction time (VRT) format. The participants were between the ages of 5.5 and 15 years. All children were presented spoken monosyllabic words of the clinical Hebrew speech discrimination test. Statistically significant differences were found, with means in the APD children reflecting slower performance than that of their peers. The two groups did not differ in their performance accuracy. These data show that combining response time measures with percent correct scores improved test sensitivity. Such an approach may hold promise for future clinical applications in the assessment of APD.