Presence of Auditory Pathway Abnormalities in Children With Neurofibromatosis Type 1 With Brainstem Focal Areas of Abnormal Signal Intensity: Diffusion Tensor Imaging Features.

Background: To investigate whether there is a difference in mean diffusivity (MD) and fractional anisotropy (FA) values in the auditory pathways of neurofibromatosis type 1 patients with and without focal areas of abnormal signal intensity (FASI) compared to healthy controls by using diffusion tensor imaging (DTI). Methods: Patients were classified as group 1 with focal areas of abnormal signal intensity in the brainstem, group 2 without focal areas of abnormal signal intensity, and healthy control group 3 according to the MRI findings. Mean diffusivity and fractional anisotropy values of lateral lemniscus, inferior colliculus, corpus geniculatum mediale, Heschl gyrus, and brainstem were compared between groups. The correlation between mean diffusivity and fractional anisotropy values of auditory pathways and age was investigated. Results: There was a significant difference between group 1 and group 2 in terms of mean diffusivity and fractional anisotropy values at lateral lemniscus, inferior colliculus, corpus geniculatum mediale, and Heschl gyrus. Increased mean diffusivity and decreased fractional anisotropy values at brainstem were found in group 1. There was a significant difference between group 1 and group 3 in terms of mean diffusivity values at all auditory pathways. Fractional anisotropy values obtained from lateral lemniscus, inferior colliculus, and Heschl gyrus decreased in group 1 compared with group 3. There was a negative correlation between mean diffusivity values and positive correlation between fractional anisotropy values at lateral lemniscus, inferior colliculus, Heschl gyrus, and age. Conclusions: Our diffusion tensor imaging findings show that the neuronal integrity of the auditory pathways is affected in neurofibromatosis type 1 patients with brainstem focal areas of abnormal signal intensity. We think that the disappearance of brainstem focal areas of abnormal signal intensity associated with myelin repair and the regression of diffusion tensor imaging changes in the auditory pathways occur simultaneously with advancing age in patients with neurofibromatosis type 1.

Central auditory processing and aphasia: A scoping review / Processamento auditivo central e afasia: uma revisão de escopo

ABSTRACT Purpose: to report scientific evidence on the impact of aphasia on central auditory processing and map the contribution of auditory training to aphasic individuals. Methods: a scoping review approaching national and international databases (SciELO, LILACS, PubMed, Scopus, and Cochrane Library) and the gray literature (Google Scholar and Open Grey). The inclusion criteria covered articles that addressed the interface between central auditory processing and aphasia, excluding duplicates, literature reviews, and scientific abstracts. Literature Review: the review comprised 13 articles that met the eligibility criteria for this study. Seven of the selected articles assessed central auditory processing, four used electrophysiological examinations (such as auditory brainstem response and long-latency auditory evoked potentials) to assess the auditory pathway, and only one analyzed the intervention in aphasic individuals with auditory training. Conclusion: scientific evidence points to an important change in aphasic people's central auditory processing, with impaired figure-ground, auditory closure, temporal resolution and ordering, and binaural integration. Moreover, it is relevant to assess auditory processing, given the contribution of auditory training in speech-language-hearing therapy for a better prognosis in the rehabilitation of aphasia.

RESUMO Objetivo: reportar as evidências científicas do impacto da afasia no Processamento Auditivo Central e mapear a contribuição do Treinamento Auditivo para a população afásica. Métodos: trata-se de uma revisão de escopo realizada nas bases de dados nacionais e internacionais: Scielo, Lilacs, Pubmed, Scopus, Cochrane Library e com uma busca adicional à literatura cinzenta no Google Scholar e Open Grey. Os critérios de inclusão abrangeram artigos que abordassem a interface do processamento auditivo central e afasia, excluindo-se as duplicações, artigos de revisão da literatura e resumos científicos. Revisão de Literatura: selecionaram-se 13 artigos que cumpriram os critérios de elegibilidade deste estudo. Dos artigos selecionados, sete apresentaram a avaliação do Processamento Auditivo Central, quatro apresentaram os exames eletrofisiológicos - como os exames de Potencial Evocado Auditivo de Tronco Encefálico (PEATE) e Potencial Evocado Auditivo de Longa Latência (PEALL) - para avaliação da via auditiva e apenas um estudo analisou a intervenção dos indivíduos afásicos por meio do treinamento auditivo. Conclusão: as evidências científicas apontam importante alteração no Processamento Auditivo Central dos afásicos, apresentando prejuízos nas habilidades auditivas de figura-fundo, fechamento auditivo, resolução e ordenação temporal e integração binaural. Ainda, demonstra-se como relevante a avaliação do processamento, devido à contribuição do Treinamento Auditivo nas terapias fonoaudiológicas para um melhor prognóstico na reabilitação das afasias.

Cortical auditory evoked potentials (P1 latency) in children with cochlear implants in relation to clinical language tests.

Objective - To study the correlation between P1 latency and the results of clinical language tests (Reynell III and TROG-2), the latter were used as they are recommended for follow-up assessments of children with cochlear implants (Cis) by the Swedish National Quality Register for children with hearing impairment.Design - A clinical cohort study.Study sample - Cross-sectional and consecutive sampling of 49 children with CIs coming for clinical follow-up assessment from March 2017 - December 2019.Results - For all children tested, there was a significant negative correlation (Spearman's rho= -0.403, p = 0.011) between hearing age and P1 latency. A significant correlation between P1 latency and the Reynell III result (Spearman's rho = -0.810, p = 0.015) was found. In the TROG-2 group, there was no significant correlation between their P1 latency and their language test results (Spearman's rho -0.239, p = 0.196).Conclusion - This method seems to be feasible and easily accepted. The study was conducted in a heterogeneous group of children that we meet daily in our clinic. The results indicated that P1 latency has a negative correlation with language development among our youngest patients fitted with CIs and might be a clinical tool to assess the maturation of central auditory pathways.

An Unusual Presentation of Hearing Impairment in an Adult with Pineal Region Germinoma: A Case Report.

Tumors of the pineal region typically present with symptoms and signs of mass effect and increased intracranial pressure. However, although rare and can be overlooked, hearing impairment is a potential clinical finding in these cases. The authors describe a 24-year-old male who presented to the emergency room complaining of bilateral hearing impairment. Brain computed tomography showed a pineal region tumor. Histopathological examination demonstrated features consistent with germinoma. This case reports a rare presentation rarely seen in the literature and in practice as evident by the conducted literature review. Therefore, we highlight the importance of considering hearing impairment as a presenting symptom of pineal region tumors since prompt recognition and intervention, as demonstrated in this case, can lead to successful outcomes.

The Auditory Agnosias: a Short Review of Neurofunctional Evidence.

PURPOSE OF REVIEW: To investigate the neurofunctional correlates of pure auditory agnosia and its varieties (global, verbal, and nonverbal), based on 116 anatomoclinical reports published between 1893 and 2022, with emphasis on hemispheric lateralization, intrahemispheric lesion site, underlying cognitive impairments. RECENT FINDINGS: Pure auditory agnosia is rare, and observations accumulate slowly. Recent patient reports and neuroimaging studies on neurotypical subjects offer insights into the putative mechanisms underlying auditory agnosia, while challenging traditional accounts. Global auditory agnosia frequently results from bilateral temporal damage. Verbal auditory agnosia strictly correlates with language-dominant hemisphere lesions. Damage involves the auditory pathways, but the critical lesion site is unclear. Both the auditory cortex and associative areas are reasonable candidates, but cases resulting from brainstem damage are on record. The hemispheric correlates of nonverbal auditory input disorders are less clear. They correlate with unilateral damage to either hemisphere, but evidence is scarce. Based on published cases, pure auditory agnosias are neurologically and functionally heterogeneous. Phenotypes are influenced by co-occurring cognitive impairments. Future studies should start from these facts and integrate patient data and studies in neurotypical individuals.

Evaluation of outcome of acoustic reflex tests in patients with type 2 diabetes mellitus: a cross-sectional study.

PURPOSE: Type 2 diabetes mellitus (T2DM) may induce micro-vascular and macro-vascular changes that can lead to neuropathic changes which may affect the auditory pathway resulting in hearing loss. The study aims to evaluate the outcome of ipsilateral and contralateral acoustic reflex (AR) parameters and reflex decay tests (RDT) in patients with T2DM, and the relationship between average AR parameters, and duration and control of T2DM. METHODS: An analytical cross-sectional study was conducted in a tertiary care setup in 126 subjects which included 42 subjects with T2DM between 30 and 60 years of age, age-matched with 84 non-diabetic subjects. The subjects were evaluated for pure tone average (PTA), speech identification score (SIS), AR parameters [acoustic reflex threshold (ART), acoustic reflex amplitude (ARA), acoustic reflex latency (ARL)] and RDT. RESULTS: The subjects with T2DM showed increased PTA in both ears when compared to the subjects with no disease. No significant difference was found in the SIS between both groups. There was no significant difference in the ART and ARL between the two groups. There was a significant difference in the ipsilateral and contralateral ARA at 500 Hz, 1000 Hz and broadband noise (BBN) when compared between the diabetic and non-diabetic groups. No significant difference was found between average AR parameters and duration and control of T2DM. CONCLUSION: T2DM increases hearing thresholds and reduces ipsilateral and contralateral AR at lower frequencies and BBN. Duration and control of T2DM do not affect the AR parameters.

Song-related brain auditory activity in Bengalese finches as examined by immediate early gene expressions: Comparison of arousal states and the correlational analyses between brain regions.

Songbirds use auditory feedback to memorize a tutor song in juveniles and to maintain it in adults. In Bengalese finches, electrophysiological studies showed the auditory responses in the premotor area HVC remained active regardless of asleep/awake status, in contrast to auditory gating phenomenon identified in zebra finches. We investigated the correlations in auditory activity between the brain regions and differences in the activity during wakefulness and sleeping in Bengalese finches. We used the immediate early gene egr-1 as a marker of neural activity that can detect regions responding to auditory stimuli in the whole brain. Results showed that auditory response, as measured by egr-1 expression to the bird's own song while sleeping and awake, was similar in HVC and NCM. Higher activity during awake than sleep was found only in the lower auditory area MLd. Analyses showed egr-1 expressions between brain regions induced by the bird's own song playback in awake/sleep conditions, suggesting that auditory information correlated with the inter part, not the outer part, of MLd with the higher song-related regions. Furthermore, the sleep condition suppressed the spontaneous activity, but not the song-induced activity in Area X. Altogether, this study presents a new attempt to explore the auditory-motor network using a molecular tool to map neurons of the nearly whole brain.

Primary degeneration of oculomotor, motor, and somatosensory systems and auditory and visual pathways in spinocerebellar ataxia type 7: A clinicopathological study in a Japanese autopsy case.

Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant neurodegenerative disorder characterized by progressive cerebellar ataxia associated with retinal degeneration. The disease is rare in Japan, and this is the first full description of clinicopathological findings in a Japanese autopsy case of genetically confirmed SCA7 having 49 cytosine-adenine-guanine (CAG) trinucleotide repeats in the ataxin 7 gene. A 34-year-old Japanese man with no family history of clinically apparent neurodegenerative diseases presented with gait disturbance, gradually followed by truncal instability with progressive visual loss by the age of 42 years. He became wheelchair-dependent by 51 years old, neurologically exhibiting cerebellar ataxia, slow eye movement, slurred and scanning speech, lower limb spasticity, hyperreflexia, action-related slowly torsional dystonic movements in the trunk and limbs, diminished vibratory sensation in the lower limbs, auditory impairment, and macular degeneration. Brain magnetic resonance imaging revealed atrophy of the brainstem and cerebellum. He died of pneumonia at age 60 with a 26-year clinical duration of disease. Postmortem neuropathological examination revealed pronounced atrophy of the spinal cord, brainstem, cerebellum, external globus pallidus (GP), and subthalamic nucleus, microscopically showing neuronal cell loss and fibrillary astrogliosis with polyglutamine-immunoreactive neuronal nuclei and/or neuronal nuclear inclusions (NNIs). Degeneration was also accentuated in the oculomotor system, auditory and visual pathways, upper and lower motor neurons, and somatosensory system, including the spinal dorsal root ganglia. There was a weak negative correlation between the frequency of nuclear polyglutamine-positive neurons and the extent of neuronal cell loss. Clinicopathological features in the present case suggest that neurological symptoms, such as oculomotor, auditory, visual, and sensory impairments, are attributable to degeneration in their respective projection systems affected by SCA7 pathomechanisms and that dystonic movement is related to more significant degeneration in the external than internal GP.

Effects of Noise and Chemical Exposure on Peripheral and Central Auditory Pathways in Normal-hearing Workers.

Objectives: To assess the effects of noise and chemical exposure on peripheral and central auditory pathways in normal-hearing workers exposed to chemicals or high noise levels and compare the groups with each other and with workers not exposed to either of these agents. Methods: A total of 54 normal-hearing workers were divided into three groups (chemical, noise, control) and submitted to the following assessments: conventional and extended high-frequency pure-tone audiometry; transient and distortion-product otoacoustic emissions, the inhibitory effect of the efferent auditory pathway; and Staggered Spondaic Word (SSW) and Pitch Pattern Sequence (PPS) test. Results: There were no significant differences between the groups in extended high-frequency hearing thresholds. Significantly lower amplitudes were observed in the noise group for otoacoustic emissions. There were significantly more absences of the inhibitory effect of the efferent system in the noise group. There was no difference between the groups in the SSW test, while in PPS, the noise group performed worse than the control group. Conclusion: These findings suggest that noise exposure produced deleterious effects on the workers' peripheral and central auditory systems, despite their normal hearing thresholds. The chemical group did not have significantly different results from those of the control group. It is important that individuals exposed to noise or chemicals have their auditory pathways monitored with complementary assessments.

Frequency and Clinical Significance of Incidental Findings Detected in Internal Acoustic Canal Magnetic Resonance Imaging of Patients with Audiovestibular Symptoms.

Objectives: Retrocochlear pathology associated with audiovestibular symptoms is detected in very few of the patients, and most of the internal acoustic canal magnetic resonance imaging examinations (IAC-MRIs) are either completely normal or include accompanying incidental findings (IFs). The aim of our study is to reveal the presence and frequency of IFs in IAC-MRIs, together with retrocochlear lesions. In addition, we intend to emphasize the clinical importance of these IFs. Methods: A retrospective analysis of 374 serial IAC-MRI scans. Results: Gender distribution: 201 males and 173 females. Age range: 2-82 years. Seventy-two scans (19.25%) were totally normal. Fifteen scans (4.01%) demonstrated only pontocerebellar angle findings (PCAFs). The presence of PCAF and IF was together in 57 scans (15.24%). In 230 (61.50%) of the scans, only IFs were present. The incidence of IFs in all IAC-MRIs was 76.74% (287 of 374). Critical findings that may require clinical further evaluation and examination were present in 34 scans (9.09%). IFs that did not require further examination were observed in 253 scans (67.65%). Conclusion: Various IFs can be detected with IAC-MRI that may cause similar symptoms with PCAF. And unfortunately, some of these IFs may be of very high clinical importance. All referral clinicians should know well that these audiovestibular symptoms can appear as IFs anywhere in the auditory pathway, and how they should be followed in their clinical approach.

Bilateral Interactions in the Mouse Dorsal Inferior Colliculus Enhance the Ipsilateral Neuronal Responses and Binaural Hearing.

The inferior colliculus (IC) is a critical centre for the binaural processing of auditory information. However, previous studies have mainly focused on the central nucleus of the inferior colliculus (ICC), and less is known about the dorsal nucleus of the inferior colliculus (ICD). Here, we first examined the characteristics of the neuronal responses in the mouse ICD and compared them with those in the inferior colliculus under binaural and monaural conditions using in vivo loose-patch recordings. ICD neurons exhibited stronger responses to ipsilateral sound stimulation and better binaural summation than those of ICC neurons, which indicated a role for the ICD in binaural hearing integration. According to the abundant interactions between bilateral ICDs detected using retrograde virus tracing, we further studied the effect of unilateral ICD silencing on the contralateral ICD. After lidocaine was applied, the responses of some ICD neurons (13/26), especially those to ipsilateral auditory stimuli, decreased. Using whole-cell recording and optogenetic methods, we investigated the underlying neuronal circuits and synaptic mechanisms of binaural auditory information processing in the ICD. The unilateral ICD provides both excitatory and inhibitory projections to the opposite ICD, and the advantaged excitatory inputs may be responsible for the enhanced ipsilateral responses and binaural summation of ICD neurons. Based on these results, the contralateral ICD might modulate the ipsilateral responses of the neurons and binaural hearing.

Comparison of continuous sampling with active noise cancelation and sparse sampling for cortical and subcortical auditory functional MRI.

PURPOSE: Detecting sound-related activity using functional MRI requires the auditory stimulus to be more salient than the intense background scanner acoustic noise. Various strategies can reduce the impact of scanner acoustic noise, including "sparse" temporal sampling with single/clustered acquisitions providing intervals without any background scanner acoustic noise, or active noise cancelation (ANC) during "continuous" temporal sampling, which generates an acoustic signal that adds destructively to the scanner acoustic noise, substantially reducing the acoustic energy at the participant's eardrum. Furthermore, multiband functional MRI allows multiple slices to be collected simultaneously, thereby reducing scanner acoustic noise in a given sampling period. METHODS: Isotropic multiband functional MRI (1.5 mm) with sparse sampling (effective TR = 9000 ms, acquisition duration = 1962 ms) and continuous sampling (TR = 2000 ms) with ANC were compared in 15 normally hearing participants. A sustained broadband noise stimulus was presented to drive activation of both sustained and transient auditory responses within subcortical and cortical auditory regions. RESULTS: Robust broadband noise-related activity was detected throughout the auditory pathways. Continuous sampling with ANC was found to give a statistically significant advantage over sparse sampling for the detection of the transient (onset) stimulus responses, particularly in the auditory cortex (P < .001) and inferior colliculus (P < .001), whereas gains provided by sparse over continuous ANC for detecting offset and sustained responses were marginal (p ~ 0.05 in superior olivary complex, inferior colliculus, medial geniculate body, and auditory cortex). CONCLUSIONS: Sparse and continuous ANC multiband functional MRI protocols provide differing advantages for observing the transient (onset and offset) and sustained stimulus responses.

Evaluation of Brainstem Subcortical Auditory Pathways with Diffusion Tensor Imaging After Gamma Knife Radiosurgery in Intracanalicular Vestibular Schwannoma.

OBJECTIVE: To investigate changes in DTI (Diffusion Tensor Imaging) parameters in brainstem subcortical auditory pathways after Gamma Knife Radiosurgery (GKR) in patients with intracanalicular vestibular schwannoma (ICVS) and to analyze the relationship between tumor volume and ADC (apparent diffusion coefficient) and FA (fractional anisotropy) values. METHOD: Seventeen patients with ICVS were evaluated before and after GKR. ADC and FA values of the lateral lemniscus (LL) and inferior colliculus (IC) and tumor volume were calculated. Patients who responded to GKR were classified as Group 1 and those who did not respond adequately as Group 2. The relationship between ADC and FA values and changes in tumor volume were analyzed. RESULTS: Tumor volume significantly decreased after GKR. ADC values obtained from the tumor increased after GKR (p:0.002). There was no significant difference in LL and IC before and after GKR in terms of FA and ADC values (n:17). There was a positive correlation between response to treatment and contralateral LL ADC values after GKR (p=0.005, r:0.652). There was a negative correlation between contralateral IC FA values after GKR and response to treatment (p=0.017, r: -0.568). There was a significant difference between Groups 1 and 2 in regards to contralateral LL ADC (p=0.03) and IC FA values (p=0.017). CONCLUSION: Since the cochlear nerve and subcortical auditory pathways have low regeneration potential after nerve damage, ADC and FA changes in LL and IC may be explained with the presence of intracanalicular tumors prior to GKR. Since GKR does not cause additional damage to the subcortical auditory pathways at the brainstem level, we think that GKR is a noninvasive treatment method that can be used safely in patients with ICVS.

Diffusion Tensor Imaging Features of the Auditory Pathways in Patients With Vestibular Schwannoma After Gamma Knife Radiosurgery.

Objective In this study, we aimed to investigate whether there is any change in diffusion tensor imaging (DTI) parameters in ipsilateral and contralateral auditory pathways after Gamma Knife radiosurgery (GKR) in patients with vestibular schwannoma (VS) and the relationship between radiosurgery variables. Methods Sixty-six patients were evaluated with MRI and DTI before and after GKR. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured from the bilateral lateral lemniscus (LL), inferior colliculus (IC), medial geniculate body (MGB), and Heschl's gyrus (HG). Results There was no significant difference in ADC and FA values obtained from bilateral LL, IC, and MGB before and after radiosurgery. However, there was a significant difference between pretreatment and post-radiosurgery contralateral HG ADC values. The ADC values obtained from the contralateral HG and IC positively correlated with the duration after radiosurgery. As the duration after radiosurgery increases, the difference between the ADC values obtained from ipsilateral and contralateral HG also increases. Conclusion The high ADC values in the contralateral HG after radiosurgery may indicate microstructural alterations such as demyelination and axonal loss. Radiation exposure doses to the brainstem and cochlea are the most important factors that can cause microstructural damage to the auditory pathways. When planning radiosurgery, extreme care should be taken to prevent the harmful effects of radiation on the auditory pathways.

Tinnitus and Neuropsychological Dysfunction in the Elderly: A Systematic Review on Possible Links.

INTRODUCTION: Tinnitus is a common and disabling symptom often associated with hearing loss. While clinical practice frequently shows that a certain degree of psychological discomfort often characterizes tinnitus suffers, it has been recently suggested in adults as a determining factor for cognitive decline affecting attention and memory domains. The aim of our systematic review was to provide evidence for a link between tinnitus, psychological distress, and cognitive dysfunction in older patients and to focus on putative mechanisms of this relationship. METHODS: We performed a systematic review, finally including 192 articles that were screened. This resulted in 12 manuscripts of which the full texts were included in a qualitative analysis. RESULTS: The association between tinnitus and psychological distress, mainly depression, has been demonstrated in older patients, although only few studies addressed the aged population. Limited studies on cognitive dysfunction in aged patients affected by chronic tinnitus are hardly comparable, as they use different methods to validate cognitive impairment. Actual evidence does not allow us with certainty to establish if tinnitus matters as an independent risk factor for cognitive impairment or evolution to dementia. CONCLUSION: Tinnitus, which is usually associated with age-related hearing loss, might negatively affect emotional wellbeing and cognitive capacities in older people, but further studies are required to improve the evidence.

Abnormal auditory event-related potentials in Williams syndrome.

Individuals with Williams Syndrome (WS) have specific auditory characteristics, including hypoacusis and hyperacusis, and music appreciation skills. Little is known about the functionality of the central auditory nervous system (CANS) for sound processing in WS. Thus, the objective of the present study was to evaluate the functionality of the CANS in individuals with WS, based on auditory event-related potentials, as far as cognitive and behavioral aspects are concerned. The study was carried out with 17 individuals, seven females and ten males, between seven and 17 years old, with WS, and 17 individuals with typical development matched by sex and chronological age to individuals with WS. None of these individuals had middle ear impairment or hearing loss. The subjects were evaluated for intelligence quotient, loudness discomfort level, and auditory event-related potentials with Tone Burst stimuli, on the oddball paradigm; the parents also answered the MTA-SNAP-IV questionnaire. Hyperacusis was found in six WS individuals and two individuals with typical development. In the present study, WS individuals present longer latency and reduced amplitude for P1, N1, N2 and P3 components. These results, suggesting a delay and hypoactive responses of the CANS in this syndrome, that cannot be related to the cognitive or behavioral aspects of these individuals, but it indicates a cortical immaturity to process acoustic stimuli.

Association between autism spectrum disorder and changes in the central auditory processing in children

SUMMARY OBJECTIVE: To verify the scientific evidence on the association between Autistic Spectrum Disorder and Central Auditory Processing Disorder in children, aiming to answer the following research question: What is the association between Autistic Spectrum and Alteration of Auditory Processing in Children? METHODS: Studies were chosen through the combination based on the Medical Subject Heading Terms (MeSH): [(auditory processing) and (children) and (autism) and (neurological disorders)]. The MEDLINE (PubMed), LILACS, and SciELO databases were used. The analyzed papers covered a ten-year period, from 2010 to 2020. We selected descriptive, cross-sectional, cohort, and case studies. We evaluated the quality of the papers, which had a minimum score of six in the modified scale of the literature. RESULTS: 126 papers were retrieved after the exclusion phase, and 17 of them followed the inclusion criteria. Only two papers answered the guiding question with audiological results. CONCLUSIONS: Patients diagnosed with autistic spectrum disorder may have disturbance central auditory processing, considering that changes were found both in absolute and interpeak latencies in the brainstem evoked response audiometry, as well as in latency and laterality of the N1c wave amplitude. In addition, there were changes in the assessment behavioral auditory processing. Thus, disturbance central auditory processing is common in children with autistic spectrum disorder.

Brain mapping of auditory steady-state responses: A broad view of cortical and subcortical sources.

Auditory steady-state responses (ASSRs) are evoked brain responses to modulated or repetitive acoustic stimuli. Investigating the underlying neural generators of ASSRs is important to gain in-depth insight into the mechanisms of auditory temporal processing. The aim of this study is to reconstruct an extensive range of neural generators, that is, cortical and subcortical, as well as primary and non-primary ones. This extensive overview of neural generators provides an appropriate basis for studying functional connectivity. To this end, a minimum-norm imaging (MNI) technique is employed. We also present a novel extension to MNI which facilitates source analysis by quantifying the ASSR for each dipole. Results demonstrate that the proposed MNI approach is successful in reconstructing sources located both within (primary) and outside (non-primary) of the auditory cortex (AC). Primary sources are detected in different stimulation conditions (four modulation frequencies and two sides of stimulation), thereby demonstrating the robustness of the approach. This study is one of the first investigations to identify non-primary sources. Moreover, we show that the MNI approach is also capable of reconstructing the subcortical activities of ASSRs. Finally, the results obtained using the MNI approach outperform the group-independent component analysis method on the same data, in terms of detection of sources in the AC, reconstructing the subcortical activities and reducing computational load.

Implications of musical practice in central auditory processing: a systematic review.

INTRODUCTION: Recent studies have shown that musical practice and training are effective and have the potential to assist in the acquisition and improvement of auditory skills. OBJECTIVE: To verify the scientific evidence on the implications of musical practice in central auditory processing. METHODS: A systematic review was carried out in accordance with the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), using the Medline (Pubmed), LILACS, SciELO, BIREME, Scopus and Web of Science databases. The search period for the articles covered the last 5 years (2015-2020), without restriction of language and location. The quality of the articles was assessed, and the review included articles with a minimum score of 6 in a modified literature quality scale. RESULTS: Initially, 1362 publications were found, of which 1338 were excluded after the title screening, 15 were excluded due to the abstract, with nine articles being analyzed in full and four of them excluded after the analysis, as they did not answer the guiding question proposed for this research. Five articles that met the proposed inclusion criteria were admitted for this research. It was found that in adults, musical ability is associated with better performance of several auditory processing skills, as well as the fact that musical training in children promoted an accelerated maturity of auditory processing and exposure to music facilitated the learning of auditory information in newborns. CONCLUSION: Considering the scientific evidence, it was found that the musical experience can improve specific skills of the central auditory processing, regardless of age, optimizing children's linguistic development.

Efeito inibitório da via eferente auditiva no transtorno de processamento auditivo central / Auditory efferent inhibitory effect in central auditory processing disorder

RESUMO Objetivo verificar e comparar a ocorrência e magnitude do efeito inibitório da via auditiva eferente em crianças e adolescentes com processamento auditivo normal e alterado, identificando um valor de corte para uso na prática clínica. Métodos estudo prospectivo, com amostra composta por 30 crianças de 7 a 14 anos, sendo 15 com avaliação de processamento auditivo normal (grupo controle) e 15 com processamento auditivo alterado (grupo estudo). Ambos os grupos foram submetidos à anamnese e avaliados por meio dos testes de emissões otoacústicas evocadas por estímulos transientes na ausência e presença de ruído contralateral, avaliação audiológica básica e de processamento auditivo. Resultados houve menor ocorrência do efeito inibitório da via eferente no grupo estudo (p-valor=0,038). Os valores médios obtidos no grupo controle foram 0,71 na orelha direita e 0,87 na orelha esquerda e no grupo estudo, 0,55 na orelha direita e 0,41 na orelha esquerda. Os grupos controle e estudo diferiram de modo significativo na orelha esquerda. Conclusão houve redução do efeito inibitório da via eferente em crianças e adolescentes com transtorno de processamento auditivo, sugerindo alteração funcional do sistema eferente olivococlear medial. O valor que separou as crianças com e sem alteração do sistema eferente foi de 0,55 dB na prática clínica, com 70% de sensibilidade e 66,7% de especificidade.

ABSTRACT Purpose Verify and compare the occurrence and magnitude of the inhibitory effect of the efferent auditory pathway in children and adolescents with normal and auditory processing disorder, identifying a cutoff value to use in clinical settings. Methods A prospective study, with a total sample of 30 children aged 7 to 14 years, half with normal auditory processing assessment (Control Group) and the other half with auditory processing disorder (Study Group). Both groups were submitted to anamnesis and evaluated using the otoacoustic emissions tests evoked by transient stimuli in the absence and presence of contralateral noise, basic audiological evaluation and auditory processing. Results The study group presented a lower occurrence of the inhibitory effect of the efferent pathway when compared to the control group (p value=0.038). The mean values ​​obtained for the control group were 0.71 in the right ear and 0.87 in the left ear and for the study group, 0.55 in the right ear and 0.41 in the left ear. The two groups showed a statistically significant difference for the left ear. Conclusion There was a reduction in the inhibitory effect of the efferent pathway in children and adolescents with auditory processing disorder, suggesting a functional change in the medial olivocochlear efferent system. In this study, the cutoff value of 0.55 dB separated children with and without alteration of the efferent system with 70% sensitivity and 66.7% specificity.