Auditory processing disorder in children diagnosed with nonverbal learning disability

PURPOSE: To determine whether children with a nonverbal learning disability (NVLD) have a higher incidence of auditory processing disorder (APD), especially in the tolerance-fading memory type of APD, and what associations could be found between performance on neuropsychological, intellectual, memory, and academic measures and APD. METHOD: Eighteen children with NVLD ranging in age from 6 to 18 years received a central auditory processing test battery to determine incidence and subtype of APD. Psychological measures for assessment of NVLD included the Wechsler Scales, Wide Range Assessment of Memory and Learning, and Wechsler Individual Achievement Test. Neuropsychological measures included the Category Test, Trails A and B, the Tactual Performance Test, Grooved Pegs, and the Speech Sounds Perception Test. Neuropsychological test scores of the NVLD+APD and NVLD groups were compared using analysis of covariance procedures, with Verbal IQ and Performance IQ as covariates. RESULTS: Sixty-one percent of the children were diagnosed with APD, primarily in the tolerance-fading memory subtype. The group of children with APD and NVLD had significantly lower scores on Verbal IQ, Digit Span, Sentence Memory, Block Design, and Speech Sounds Perception than children without APD. An ancillary finding was that the incidence of attention deficit/hyperactivity disorder was significantly higher in children with NVLD (with and without APD) than in the general population. CONCLUSION: The results indicate that children with NVLD are at risk for APD and that there are several indicators on neuropsychological assessment suggestive of APD. Collaborative, interdisciplinary evaluation of children with learning disorders is needed in order to provide effective therapeutic interventions.     

Auditory evoked potentials as measures of plasticity in humans.

There is increasing evidence from animal studies for plasticity of auditory function. This has prompted research to determine whether such plastic changes occur in adults and children with hearing disorders. Behavioural measures such as speech perception scores do show improvements after hearing aid fitting and cochlear implantation. Several studies have also shown changes in cortical auditory evoked potentials after cochlear implantation and after auditory training. These studies indicate that improvements in speech perception ability are associated with changes in the central auditory system, particularly at the cortical level.     

Auditory Neuropathy / Auditory Dyssynchrony in children with Cochlear Implants

The electrical stimulation generated by the Cochlear Implant (CI) may improve the neural synchrony and hence contribute to the development of auditory skills in patients with Auditory Neuropathy / Auditory Dyssynchrony (AN/AD).AimProspective cohort cross-sectional study to evaluate the auditory performance and the characteristics of the electrically evoked compound action potential (ECAP) in 18 children with AN/AD and cochlear implants.Material and methodsThe auditory perception was evaluated by sound field thresholds and speech perception tests. To evaluate ECAP's characteristics, the threshold and amplitude of neural response were evaluated at 80Hz and 35Hz.ResultsNo significant statistical difference was found concerning the development of auditory skills. The ECAP's characteristics differences at 80 and 35Hz stimulation rate were also not statistically significant.ConclusionThe CI was seen as an efficient resource to develop auditory skills in 94% of the AN/ AD patients studied. The auditory perception benefits and the possibility to measure ECAP showed that the electrical stimulation could compensate for the neural dyssynchrony caused by the AN/AD. However, a unique clinical procedure cannot be proposed at this point. Therefore, a careful and complete evaluation of each AN/AD patient before recommending a Cochlear Implant is advised. Clinical Trials: NCT01023932     

Auditory and communication learning in patients with cochlear implants

Nowadays the cochlear implant (CI) offers a new method of hearing, especially for deaf patients who do not benefit from conventional hearing aids. However, it may be difficult to get used to this kind of hearing advice. CI users have special problems in interpreting strange acoustic sensations and relating them to auditory features of language and noise they knew before the onset of deafness. An interdisciplinary approach is very important for rehabilitation. Beside otological examination and the surgical implantation, audiological assessment is needed for the correct adjustment of the speech processor and for measurement of performance. Also auditory management and counselling of deaf patients is an important part of CI rehabilitation. A learning programme in hearing and communicating ("hearing training") is offered to CI users that takes account of different linguistic levels. Auditory learning by the use of CI is based on different abilities of the deaf patient, of which the most important are speech skills and learning capacity. Although success rates vary, it certainly improves speech intelligibility during lip reading, communication behaviour, and recognition of environmental noise. The latter ability improves orientation in the acoustic surroundings. CI rehabilitation may improve the psychosocial attitude of the deaf.     

Auditory plasticity and hyperactivity following cochlear damage

This paper will review some of the functional changes that occur in the central auditory pathway after the cochlea is damaged by acoustic overstimulation or by carboplatin, an ototoxic drug that selectively destroys inner hair cells (IHCs) in the chinchilla. Acoustic trauma typically impairs the sensitivity and tuning of auditory nerve fibers and reduces the neural output of the cochlea. Surprisingly, our results show that restricted cochlear damage enhances neural activity in the central auditory pathway. Despite a reduction in the auditory-nerve compound action potential (CAP), the local field potential from the inferior colliculus (IC) increases at a faster than normal rate and its maximum amplitude is enhanced at frequencies below the region of hearing loss. To determine if this enhancement was due to loss of sideband inhibition, we recorded from single neurons in the IC and dorsal cochlear nucleus before and after presenting a traumatizing above the unit's characteristic frequency (CF). Following the exposure, some neurons showed substantial broadening of tuning below CF, less inhibition, and a significant increase in discharge rate, consistent with a model involving loss of sideband inhibition. The central auditory system of the chinchilla can be deprived of some of its cochlear inputs by selectively destroying IHCs with carboplatin. Selective IHC loss reduces the amplitude of the CAP without affecting the threshold and tuning of the remaining auditory nerve fibers. Although the output of the cochlea is reduced in proportion to the amount of IHC loss, the IC response shows only a modest amplitude reduction, and remarkably, the response of the auditory cortex is enhanced. These results suggest that the gain of the central auditory pathway can be up- or down regulated to compensate for the amount of neural activity from the cochlea.     

Tinnitus and neural plasticity of the brain.

OBJECTIVE: To describe the current ideas about the manifestations of neural plasticity in generating tinnitus. DATA SOURCES: Recently published source articles were identified using MEDLINE, PubMed, and Cochrane Library according to the key words mentioned below. STUDY SELECTION: Review articles and controlled trials were particularly selected. DATA EXTRACTION: Data were selected systematically, scaled on validity and comparability. CONCLUSION: An altered afferent input to the auditory pathway may be the initiator of a complex sequence of events, finally resulting in the generation of tinnitus at the central level of the auditory nervous system. The effects of neural plasticity can generally be divided into early modifications and modifications with a later onset. The unmasking of dormant synapses, diminishing of (surround) inhibition and initiation of generation of new connections through axonal sprouting are early manifestations of neural plasticity, resulting in lateral spread of neural activity and development of hyperexcitability regions in the central nervous system. The remodeling process of tonotopic receptive fields within auditory pathway structures (dorsal cochlear nucleus, inferior colliculus, and the auditory cortex) are late manifestations of neural plasticity. The modulation of tinnitus by stimulating somatosensory or visual systems in some people with tinnitus might be explained via the generation of tinnitus following the nonclassical pathway. The similarities between the pathophysiological processes of phantom pain sensations and tinnitus have stimulated the theory that chronic tinnitus is an auditory phantom perception.     

Auditory pathway function after vestibular schwannoma surgery.

We studied seven patients before and after vestibular schwannoma surgery. Four patients became unilaterally profoundly deaf and three patients preserved their hearing. Cortical responses were recorded with a 122-channel whole-scalp SQUID neuromagnetometer using tone-burst stimuli to the healthy ear. Brainstem auditory evoked potentials (BAEPs) were measured using alternating clicks. Ten healthy volunteers served as a control group. In patients, preoperative cortical response latencies and strengths did not differ significantly from those of controls. However, 6 months after the operation the latency was, on average, 7 ms longer than preoperatively over both hemispheres. BAEPs were in the normal range both before and after the operation. These results suggest that unilateral lesion in peripheral auditory pathways also affects cortical reactivity to stimuli presented to the non-affected ear, possibly reflecting altered binaural interaction in the auditory pathways.     

Auditory brainstem response,middle latency response,and late cortical evoked potentials in children with learning disabilities

Auditory evoked potentials (AEPs) and behavioral tests were used to evaluate auditory processing in 10 children aged 7 to 11 years who were diagnosed as learning disabled (LD). AEPs included auditory brainstem responses (ABRs), middle latency responses (MLRs), and late cortical responses (P1, N1, P2, P3). Late cortical responses were recorded using an active listening oddball procedure. Auditory processing disorders were suspected in the LD children after a psychologist found phonologic processing and auditory memory problems. A control group of 10 age- and gender-matched children with no hearing or reported learning difficulties was also tested. Teacher ratings of classroom listening and SCAN Competing Words and Staggered Spondaic Word scores were poorer in the LD children. There were minor ABR latency differences between the two groups. Wave Na of the MLR was later and Nb was smaller in the LD group. The main differences in cortical responses were that P1 was earlier and P3 was later and smaller in the LD group.     

Auditory training induces asymmetrical changes in cortical neural activity.

Pre-attentive cortical evoked potentials reflect training-induced changes in neural activity associated with speech-sound training. Seven normal-hearing young adults were trained to identify two synthetic speech variants of the syllable /ba/. As subjects learned to correctly identify the two stimuli, changes in P1, N1, and P2 amplitudes were observed. Of particular interest is that P1, N1, and P2 components of the N1-P2 complex responded differently to listening training. That is, significant changes in P1 and N1 amplitude were recorded over the right but not the left hemisphere. In contrast, increases in P2 were observed bilaterally. These results indicate that training-related changes in neural activity are reflected in far-field aggregate neural responses and that distinct patterns of neural change, perhaps reflecting hemispheric specialization, likely represent different aspects of auditory function.     

Auditory characteristics of children with autism

OBJECTIVES: The objectives of this study were (1) to describe the auditory characteristics of children with autism relative to those of typically developing children and (2) to describe the test-retest reliability of behavioral auditory test measures with this population of children with autism. DESIGN: Audiometric data were obtained from 22 children diagnosed with autism and 22 of their typically developing peers. The audiologic test battery consisted of behavioral measures (i.e., visual reinforcement audiometry, tangible reinforcement operant conditioning audiometry, and conditioned play audiometry) and physiological measures (auditory brain stem response audiometry, distortion product otoacoustic emissions, and acoustic reflexes). RESULTS: Children with autism had physiologic test results equivalent to their typically developing counterparts. That is, no differences in auditory brain stem response audiometry, distortion product otoacoustic emissions, or acoustic reflex results were noted between the children with autism and typically developing children. However, behavioral measures revealed that about half of the children diagnosed with autism presented pure-tone averages outside of normal limits (i.e., >20 dB HL), although their response thresholds to speech were within normal limits. All behavioral test results were within normal limits (i.e., 20 dB HL) despite having normal to near-normal hearing sensitivity as determined by other audiometric measures.     

Auditory neuropathy in children

Auditory neuropathy is a sensorineural disorder characterized by absent or abnormal auditory brainstem evoked potentials and normal cochlear outer hair cell function. A variety of processes is thought to be involved in its pathophysiology and their influence on hearing may be different. We present here the diagnostic sequence and management of two new cases of auditory neuropathy in breastfeeding children.     

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.     

Auditory sequential organization among children with and without a hearing loss.

The present investigation examined the ability of children with and without a hearing loss to correctly reproduce sequences of acoustic stimuli that varied in number, temporal spacing, and type. Forty-eight children took part in the investigation. They were divided into four groups: two groups of 6- and 7-year-old children, 12 with normal hearing and 12 with a sensorineural hearing loss; and two groups of 9- and 10-year-old children, 12 with normal hearing and 12 with a sensorineural hearing loss. All of the children completed auditory temporal sequencing tasks with verbal (/ba/ and /da/) and nonverbal (a 1-kHz pure tone and a wide band noise) acoustic stimuli. For the 6- and 7-year-old children, the results revealed a significant difference between the children with a hearing loss and their peers with normal hearing for immediate recall of verbal sequences. There were no significant differences in performance between the children with a hearing loss and their peers with normal hearing on the nonverbal sequencing tasks or on the nonverbal and verbal memory span tasks. For the 9- and 10-year-old children, the results did not show any significant differences in performance between the two groups of children for the reproduction of sequences containing more than two verbal or nonverbal elements nor for the auditory memory span task when the sequences consisted of verbal stimuli. For the recall of two verbal stimuli with a variable interstimulus interval (ISI) duration, the results showed that the children with a hearing loss experienced more difficulty than the children with normal hearing. Overall, the results indicated that on the auditory sequential organization tasks, the poorer performance of the children with a hearing loss is likely attributable to auditory perceptual processing deficits rather than to poorer short-term memory capabilities. Also, an analysis of the data revealed that the older children obtained significantly better results than the younger children on auditory sequential organization tasks.     

Auditory pathway in rheumatoid arthritis. A comparative study and surgical perspectives

Conclusion. Rheumatoid arthritis (RA) patients present with both conductive and sensorineural deafness. Objective. To evaluate the prevalence and features of hearing impairment in patients with RA. Material and methods. A total of 28 RA patients underwent a rheumatological evaluation, including determination of rheumatoid factor, protein 2-glycoprotein I level and the Lee index. An audiological assessment consisting of pure-tone audiometry (PTA) and determination of auditory brainstem responses (ABRs) and transient evoked otoacoustic emissions (TEOAEs) was performed. The results were compared with those of 28 age- and sex-matched healthy subjects. Four selected RA patients underwent stapedectomy; PTA and TEOAEs were evaluated 6 months postoperatively. Results. Increased air conduction thresholds at 250, 500 and 1000 Hz were found in RA subjects in comparison to controls (p<0.001). RA patients showed higher air–bone gaps in PTA (p<0.05) and an increased Wave I latency in ABRs (p=0.03). Decreased reproducibility (p<0.001) and amplitude (p<0.001) of TEOAEs were found in RA subjects in comparison to controls. A significant correlation between disease duration and echo amplitude was noticed (r=0.389). After stapedectomy, a reduction in the air–bone conduction gap (11 vs 2 dB HL) was noticed; no significant difference in TEOAEs was found.     

Auditory pathway in rheumatoid arthritis. A comparative study and surgical perspectives

CONCLUSION: Rheumatoid arthritis (RA) patients present with both conductive and sensorineural deafness. OBJECTIVE: To evaluate the prevalence and features of hearing impairment in patients with RA. MATERIAL AND METHODS: A total of 28 RA patients underwent a rheumatological evaluation, including determination of rheumatoid factor, protein 2-glycoprotein I level and the Lee index. An audiological assessment consisting of pure-tone audiometry (PTA) and determination of auditory brainstem responses (ABRs) and transient evoked otoacoustic emissions (TEOAEs) was performed. The results were compared with those of 28 age- and sex-matched healthy subjects. Four selected RA patients underwent stapedectomy; PTA and TEOAEs were evaluated 6 months postoperatively. RESULTS: Increased air conduction thresholds at 250, 500 and 1000 Hz were found in RA subjects in comparison to controls (p<0.001). RA patients showed higher air-bone gaps in PTA (p<0.05) and an increased Wave I latency in ABRs (p=0.03). Decreased reproducibility (p<0.001) and amplitude (p<0.001) of TEOAEs were found in RA subjects in comparison to controls. A significant correlation between disease duration and echo amplitude was noticed (r=0.389). After stapedectomy, a reduction in the air-bone conduction gap (11 vs 2 dB HL) was noticed; no significant difference in TEOAEs was found.