Childhood auditory processing disorder as a developmental disorder: the case for a multi-professional approach to diagnosis and management

Interventions for School-Aged Children with Auditory Processing Disorder: A Scoping Review

(1) Background: Auditory processing (AP) disorder is associated with learning difficulties and poses challenges to school-aged children in their daily activities. This scoping review identifies interventions and provides audiologists with protocol insights and outcome measures. (2) Methods: A systematic search of both peer-reviewed and grey literature (January 2006 to August 2023) covered ten databases. Studies included had the following characteristics: (i) published in French or English; (ii) participants were school-aged, and had a normal audiogram, AP difficulties or disorder, and no cognitive, developmental, congenital or neurological disorder (with the exception of learning, attention, and language disabilities); (iii) were intervention studies or systematic reviews. (3) Results: Forty-two studies were included, and they predominantly featured auditory training (AT), addressing spatial processing, dichotic listening, temporal processing and listening to speech in noise. Some interventions included cognitive or language training, assistive devices or hearing aids. Outcome measures listed included electrophysiological, AP, cognitive and language measures and questionnaires addressed to parents, teachers or the participants. (4) Conclusions: Most interventions focused on bottom-up approaches, particularly AT. A limited number of top-down approaches were observed. The compiled tools underscore the need for research on metric responsiveness and point to the inadequate consideration given to understanding how children perceive change.

Peripheral Anomalies in USH2A Cause Central Auditory Anomalies in a Mouse Model of Usher Syndrome and CAPD

Central auditory processing disorder (CAPD) is associated with difficulties hearing and processing acoustic information, as well as subsequent impacts on the development of higher-order cognitive processes (i.e., attention and language). Yet CAPD also lacks clear and consistent diagnostic criteria, with widespread clinical disagreement on this matter. As such, identification of biological markers for CAPD would be useful. A recent genome association study identified a potential CAPD risk gene, USH2A. In a homozygous state, this gene is associated with Usher syndrome type 2 (USH2), a recessive disorder resulting in bilateral, high-frequency hearing loss due to atypical cochlear hair cell development. However, children with heterozygous USH2A mutations have also been found to show unexpected low-frequency hearing loss and reduced early vocabulary, contradicting assumptions that the heterozygous (carrier) state is "phenotype free". Parallel evidence has confirmed that heterozygous Ush2a mutations in a transgenic mouse model also cause low-frequency hearing loss (Perrino et al., 2020). Importantly, these auditory processing anomalies were still evident after covariance for hearing loss, suggesting a CAPD profile. Since usherin anomalies occur in the peripheral cochlea and not central auditory structures, these findings point to upstream developmental feedback effects of peripheral sensory loss on high-level processing characteristic of CAPD. In this study, we aimed to expand upon the mouse behavioral battery used in Perrino et al. (2020) by evaluating central auditory brain structures, including the superior olivary complex (SOC) and medial geniculate nucleus (MGN), in heterozygous and homozygous Ush2a mice. We found that heterozygous Ush2a mice had significantly larger SOC volumes while homozygous Ush2a had significantly smaller SOC volumes. Heterozygous mutations did not affect the MGN; however, homozygous Ush2a mutations resulted in a significant shift towards more smaller neurons. These findings suggest that alterations in cochlear development due to USH2A variation can secondarily impact the development of brain regions important for auditory processing ability.

Learning difficulties and auditory processing deficits in a clinical sample of primary school-aged children

Objective: The current study examined the relationship between learning and auditory processing (AP) ability in a clinical sample of children with and without learning difficulties (LD).Design: A non-randomised, cross-sectional, single measure research design was used.Study sample: The participants consisted of 50 children (7.7-10.8 years) who had been referred for a clinical AP assessment based on having been referred from a school-based AP screening. These children had previously been identified as having (n = 14) or not having (n = 36) LD.Results: Children with LD performed significantly worse than children without LD on frequency patterns with linguistic reports (FP_linR and FP_linL), dichotic digits (DD) and Auditory Word Memory - Forward (ANM_F) tests, with significant correlations being observed between these variables and the learning score. The multiple linear regression showed that FP_linR, DD_R and ANM_F scores explained 50% of the variance in the learning score.Conclusion: The present study's results are most consistent with risk factor models linking AP to learning abilities in children where reduced AP abilities could put children at greater risk for LD. Further investigations into the potential relationships between AP, cognition, speech and language development, and learning ability in children are warranted.

Multi-level evidence of an allelic hierarchy of USH2A variants in hearing, auditory processing and speech/language outcomes

Language development builds upon a complex network of interacting subservient systems. It therefore follows that variations in, and subclinical disruptions of, these systems may have secondary effects on emergent language. In this paper, we consider the relationship between genetic variants, hearing, auditory processing and language development. We employ whole genome sequencing in a discovery family to target association and gene x environment interaction analyses in two large population cohorts; the Avon Longitudinal Study of Parents and Children (ALSPAC) and UK10K. These investigations indicate that USH2A variants are associated with altered low-frequency sound perception which, in turn, increases the risk of developmental language disorder. We further show that Ush2a heterozygote mice have low-level hearing impairments, persistent higher-order acoustic processing deficits and altered vocalizations. These findings provide new insights into the complexity of genetic mechanisms serving language development and disorders and the relationships between developmental auditory and neural systems.

Auditory processing disorders in incarcerated youth: A call for early detection and treatment

BACKGROUND

Numerous reports have linked language impairment, academic underachievement, and attention disorder to misbehavior in adolescence. Recent studies have found an association between deficits in hearing and auditory processing and involvement in the juvenile justice system. In fact, the existence of an auditory processing disorder (APD) is a risk factor for adolescent delinquency even in the presence of normal hearing. The nexus between APD, low academic achievement and offending behavior in teens has prompted recommendation for early screening of school children for abnormalities in auditory processing. Using a variety of diagnostic tools, investigators have found an increase in the frequency of APD in cohorts of confined youthful offenders. The present investigation evaluates the prevalence of APD in a group of incarcerated youth residing in a detention center.

METHODS

A total of 52 incarcerated adolescents (8 females and 44 males; age range 13-20 (M = 16.0), residing at a juvenile detention center in Pittsburgh, Pennsylvania and determined to have normal auditory acuity were included in the study. All participants were screened for APD using two dichotic listening tests, the Randomized Dichotic Digits Test (RDDT) and the Dichotic Words Test (DWT), evaluative modalities to identify deficits in auditory processing. The prevalence of APD in the study group was compared to previously published normative data for non-offending age-matched youth.

RESULTS

On the RDDT, 23.1% of participants demonstrated normal auditory processing, while 77% had abnormal test results. On the DWT, 75% of subjects exhibited normal auditory processing, while the scores were abnormal for 24.9%. When the results of the RDDT and the DWT were combined to establish a pattern for the purpose of interpreting a deficit, 21.1% of the participants produced results that were within normal limits, while 17.3% qualified for a diagnosis of APD, with abnormal results on both tests. Previous studies have estimated the prevalence of auditory processing disorder in the general adolescent population as being between 2% and 7%.

CONCLUSIONS

This study found a higher prevalence of auditory processing disorder in a cohort of incarcerated youth compared with age-matched controls. Diagnostic screening protocols that identify at-risk children have been developed, as have effective therapies to improve auditory processing function. Teachers, pediatricians and psychologists should consider APD in children and adolescents with behaviors that may increase their risk for juvenile justice involvement. Studies on optimal timing and strategies for assessing and treating APD in children and adolescents are needed, including youth caught up in the juvenile justice system.

The Effect of Presentation Level on the SCAN-3 in Children and Adults

PURPOSE

The pediatric and adult versions of the SCAN-3 test (Keith, 2009a, 2009b) are widely used to screen and diagnose auditory processing disorders. According to the instruction manual, the test administration is flexible in that it may be administered through an audiometer at 50 dB HL or a portable CD player at the patient or administrator's most comfortable listening level (MCL). Because MCL may vary across individuals, even in those with normal hearing sensitivity, this study explored whether the presentation level affected scores on the SCAN-3 for both pediatric and adult populations.

METHOD

Twenty-two young adults and 23 children with normal hearing sensitivity and middle ear function were administered the SCAN-3 three different times at 1-month intervals, at 40, 50, and 60 dB HL. The stimulus level of the SCAN-3 was counterbalanced across participants to eliminate test order effects. In addition, MCL was measured in the pediatric participants during each session.

RESULTS

MCL varied significantly across children as well as between test sessions, ranging from 40 to 75 dB HL. Performance on 3 of the 4 subtests administered, as well as composite scores, was significantly different across presentation levels (based on scaled scores). Effect sizes were also calculated and found to be strong. The number of composite scores interpreted as within normal limits versus borderline or disordered was also statistically different across presentation levels.

CONCLUSIONS

Presentation level appears to affect performance on auditory figure ground, monaural low-redundancy, and binaural integration types of auditory processing tasks that are measured by the SCAN-3. In children, MCL was found to vary significantly both between and within individuals. Although several professions outside audiology are qualified to administer the SCAN-3, it is likely that many of these individuals administer the test without an audiometer and would use an MCL to determine presentation level. It is recommended that SCAN-3 users administer the test through an audiometer at 50 dB HL, rather than with a portable CD player, using MCL values to avoid any presentation level effects.

Common Misconceptions Regarding Pediatric Auditory Processing Disorder

Pediatric hearing evaluation based on pure tone audiometry does not always reflect how a child hears in everyday life. This practice is inappropriate when evaluating the difficulties children experiencing auditory processing disorder (APD) in school or on the playground. Despite the marked increase in research on pediatric APD, there remains limited access to proper evaluation worldwide. This perspective article presents five common misconceptions of APD that contribute to inappropriate or limited management in children experiencing these deficits. The misconceptions discussed are (1) the disorder cannot be diagnosed due to the lack of a gold standard diagnostic test; (2) making generalizations based on profiles of children suspected of APD and not diagnosed with the disorder; (3) it is best to discard an APD diagnosis when another disorder is present; (4) arguing that the known link between auditory perception and higher cognition function precludes the validity of APD as a clinical entity; and (5) APD is not a clinical entity. These five misconceptions are described and rebutted using published data as well as critical thinking on current available knowledge on APD.

The practices, challenges and recommendations of South African audiologists regarding managing children with auditory processing disorders

Audiologists managing children with auditory processing disorders (APD) encounter challenges that include conflicting definitions, several classification profiles, problems with differential diagnosis and a lack of standardised guidelines. The heterogeneity of the disorder and its concomitant childhood disorders makes diagnosis difficult. Linguistic and cultural issues are additional challenges faced by South African audiologists. The study aimed to describe the practices, challenges and recommendations of South African audiologists managing children with APD. A quantitative, non-experimental descriptive survey was used to obtain data from 156 audiologists registered with the Health Professions of South Africa. Findings revealed that 67% screened for APD, 42% assessed while 43% provided intervention. A variety of screening and assessment procedures were being administered, with no standard test battery identified. A range of intervention strategies being used are discussed. When the relationship between the number of years of experience and the audiologists' level of preparedness to practice in the field of APD was compared, a statistically significant difference (p = 0.049) was seen in that participants with more than 10 years of experience were more prepared to practice in this area. Those participants having qualified as speech-language therapists and audiologists were significantly more prepared (p = 0.03) to practice than the audiologists who comprised the sample. Challenges experienced by the participants included the lack of linguistically and culturally appropriate screening and assessment tools and limited normative data. Recommendations included reviewing the undergraduate audiology training programmes, reinstituting the South African APD Taskforce, developing linguistically and culturally appropriate normative data, creating awareness among educators and involving them in the multidisciplinary team.

Central auditory processing disorder profile in premature and term infants

OBJECTIVE

The aim of this study is to compare central auditory processing disorder (CAPD) profile between children born prematurely and at term.

METHODS

A retrospective study involving children 7 to 13 years of age who were referred for CAPD evaluation over the past 3 years. Parental reports and medical records were used to collect information. Children with a score ≥ two standard deviations below the mean for at least one ear on at least two different CAPD tests were considered to have CAPD.

RESULTS

A total of 82 children were evaluated for CAPD of which 22 met exclusion criteria, resulting in 60 children with CAPD (15 premature and 45 term). Premature children had higher prevalence of cesarean section delivery and neonatal jaundice compared with term children. Premature children had a higher total number of failed CAPD tests compared with the term children. Among CAPD tests, there was an increased frequency of abnormal Phonemic Synthesis test (PST) and decreased frequency of abnormal Staggered Spondaic Word test (SSW) among premature children compared with term children.

CONCLUSION

Premature children differ in CAPD profile compared with term children. Findings suggest possible etiological differences for CAPD such as jaundice or differential susceptibility of premature children for altered PST and SSW performance when compared with the term children.

A long-term follow-up of children and adolescents referred for assessment of auditory processing disorder

OBJECTIVE

This study investigated whether young adults (between 18 and 30 years at the time of the project) who were assessed for auditory processing disorder (APD) in childhood (between 7 and 16 years) experience persistence of listening and communication difficulties.

DESIGN

Participants completed a mixed methods questionnaire focusing on common areas of complaint in APD and two open-ended questions exploring participants' past and present experiences with listening and communication difficulties.

STUDY SAMPLE

Ninety-seven of the 722 potential participants returned completed questionnaires, of whom 66 had been diagnosed with APD (APD group) at the time of their auditory processing assessment and 31 had not met diagnostic criteria (NAPD group) at that time.

RESULTS

Substantial commonality was noted in the reported listening and communication difficulties between the APD and NAPD participants. Volunteered comments aggregated into four major content themes which included: listening and communication difficulties; participants' sense of self; change; and participation. Members of the APD group reported greater communication difficulty than NAPD group members, irrespective of environmental listening conditions.

CONCLUSIONS

Young adults with a prior referral for, and in some cases a diagnosis of, APD as children continue to experience auditory processing difficulties across a range of daily situations.

Patient-reported speech in noise difficulties and hyperacusis symptoms and correlation with test results

OBJECTIVES/HYPOTHESIS

To compare self-reported symptoms of difficulty hearing speech in noise and hyperacusis in adults with auditory processing disorders (APDs) and normal controls; and to compare self-reported symptoms to objective test results (speech in babble test, transient evoked otoacoustic emission [TEOAE] suppression test using contralateral noise).

STUDY DESIGN

A prospective case-control pilot study.

METHODS

Twenty-two participants were recruited in the study: 10 patients with reported hearing difficulty, normal audiometry, and a clinical diagnosis of APD; and 12 normal age-matched controls with no reported hearing difficulty. All participants completed the validated Amsterdam Inventory for Auditory Disability questionnaire, a hyperacusis questionnaire, a speech in babble test, and a TEOAE suppression test using contralateral noise.

RESULTS

Patients had significantly worse scores than controls in all domains of the Amsterdam Inventory questionnaire (with the exception of sound detection) and the hyperacusis questionnaire (P < .005). Patients also had worse TEOAE suppression test results in both ears than controls; however, this result was not significant after Bonferroni correction. Strong correlations were observed between self-reported symptoms of difficulty hearing speech in noise and speech in babble test results in the right ear (ρ = 0.624, P = .002), and between self-reported symptoms of hyperacusis and TEOAE suppression test results in the right ear (ρ = -0.597 P = .003).

CONCLUSIONS

There was no significant correlation between the two tests. A strong correlation was observed between right ear speech in babble and patient-reported intelligibility of speech in noise, and right ear TEOAE suppression by contralateral noise and hyperacusis questionnaire.

Cognitive training for impaired neural systems in neuropsychiatric illness

Neuropsychiatric illnesses are associated with dysfunction in distributed prefrontal neural systems that underlie perception, cognition, social interactions, emotion regulation, and motivation. The high degree of learning-dependent plasticity in these networks-combined with the availability of advanced computerized technology-suggests that we should be able to engineer very specific training programs that drive meaningful and enduring improvements in impaired neural systems relevant to neuropsychiatric illness. However, cognitive training approaches for mental and addictive disorders must take into account possible inherent limitations in the underlying brain 'learning machinery' due to pathophysiology, must grapple with the presence of complex overlearned maladaptive patterns of neural functioning, and must find a way to ally with developmental and psychosocial factors that influence response to illness and to treatment. In this review, we briefly examine the current state of knowledge from studies of cognitive remediation in psychiatry and we highlight open questions. We then present a systems neuroscience rationale for successful cognitive training for neuropsychiatric illnesses, one that emphasizes the distributed nature of neural assemblies that support cognitive and affective processing, as well as their plasticity. It is based on the notion that, during successful learning, the brain represents the relevant perceptual and cognitive/affective inputs and action outputs with disproportionately larger and more coordinated populations of neurons that are distributed (and that are interacting) across multiple levels of processing and throughout multiple brain regions. This approach allows us to address limitations found in earlier research and to introduce important principles for the design and evaluation of the next generation of cognitive training for impaired neural systems. We summarize work to date using such neuroscience-informed methods and indicate some of the exciting future directions of this field.

Medio-frontal and anterior temporal abnormalities in children with attention deficit hyperactivity disorder (ADHD) during an acoustic antisaccade task as revealed by electro-cortical source reconstruction

BACKGROUND

Attention Deficit Hyperactivity Disorder (ADHD) is one of the most prevalent disorders in children and adolescence. Impulsivity is one of three core symptoms and likely associated with inhibition difficulties. To date the neural correlate of the antisaccade task, a test of response inhibition, has not been studied in children with (or without) ADHD.

METHODS

Antisaccade responses to visual and acoustic cues were examined in nine unmedicated boys with ADHD (mean age 122.44 ± 20.81 months) and 14 healthy control children (mean age 115.64 ± 22.87 months, three girls) while an electroencephalogram (EEG) was recorded. Brain activity before saccade onset was reconstructed using a 23-source-montage.

RESULTS

When cues were acoustic, children with ADHD had a higher source activity than control children in Medio-Frontal Cortex (MFC) between -230 and -120 ms and in the left-hemispheric Temporal Anterior Cortex (TAC) between -112 and 0 ms before saccade onset, despite both groups performing similarly behaviourally (antisaccades errors and saccade latency). When visual cues were used EEG-activity preceding antisaccades did not differ between groups.

CONCLUSION

Children with ADHD exhibit altered functioning of the TAC and MFC during an antisaccade task elicited by acoustic cues. Children with ADHD need more source activation to reach the same behavioural level as control children.

Auditive Verarbeitungs- und Wahrnehmungsstörungen (AVWS) im Kindesalter

Auditive Verarbeitungs- und Wahrnehmungsstörungen (AVWS) sind umschriebene Funktionsdefizite in der auditiven Informationsverarbeitung und Wahrnehmung bei intaktem peripherem Gehör und mindestens durchschnittlicher Intelligenz. Häufig sind Lernstörungen, primäre bzw. sekundäre Spracherwerbsstörungen, supramodale Aufmerksamkeitsprobleme oder tiefgreifende Entwicklungsstörungen mit AVWS im Sinn von Komorbidität assoziiert. Deswegen erscheint Eltern, Lehrern oder Untersuchern das AVWS-Konzept zur Erklärung solcher Entwicklungs- und Lernauffälligkeiten plausibel. Da Sprachsignale zerebral anders als nicht sprachliche Signale ausgewertet werden, kann Sprachwahrnehmung allenfalls als ein Spezialfall der auditiven Verarbeitung und Wahrnehmung betrachtet werden. Kausale Beziehungen zwischen gestörten auditiven Funktionen und klinischen Störungsbildern wurden bislang nicht zuverlässig belegt. Es besteht ein Mangel an kontrollierten bzw. randomisierten Therapiestudien.