Potencial evocado auditivo de média latência em crianças com dificuldades de aprendizagem

INTRODUÇÃO: Trata-se de uma semiologia laboratorial objetiva para avaliação do sistema auditivo de crianças com distúrbio de aprendizagem. OBJETIVO: Examinar os componentes do potencial evocado auditivo de média latência em uma amostra de crianças com distúrbio de aprendizagem e determinar suas propriedades. MÉTODO: O estudo realizado é do tipo prospectivo contemporâneo de corte transversal, quantitativo, descritivo e exploratório. 50 crianças de ambos os sexos com 8 a 14 anos de idade dividido em dois grupos iguais, com e sem distúrbio de aprendizagem. Causas orgânicas, ambientais ou genéticas foram excluídas do estudo. RESULTADOS E CONCLUSÃO: As ondas Na, Pa, Nb foram identificadas em todos os integrantes do estudo. Os valores de latência dos componentes foram Na= 19,2 ms, Pa= 32,5 ms, Nb= 46,4 ms (grupo controle) e Na= 19,7 ms, Pa= 35,1 ms, Nb= 49,6 ms (grupo pesquisa). O valor médio de amplitude Na-Pa foi 1,4 mV para ambos os grupos. As análises mostraram diferenças funcionais entre os grupos, foi observado o hemisfério esquerdo Nb latência mais longa de Nb no hemisfério esquerdo do grupo de estudo em relação ao controle. Tal estudo promoveu informações adicionais sobre PEAML e pode ser referência para outros estudos clínicos e experimentais nesta população.

Auditory processing in children and adolescents in situations of risk and vulnerability

CONTEXTO E OBJETIVO: Crianças e adolescentes que vivem em situação de vulnerabilidade social apresentam uma série de problemas de saúde. Apesar disso, ainda é controversa a afirmação sobre a existência de alterações cognitivas e/ou sensoriais. O objetivo deste estudo foi investigar aspectos relacionados ao processamento auditivo, através da aplicação de testes de potencial evocado auditivo de tronco encefálico (PEATE) e avaliação comportamental do processamento auditivo em crianças em situação de rua, comparando a um grupo controle. TIPO DE ESTUDO E LOCAL: Estudo transversal no Laboratório de Processamento Auditivo, Faculdade de Medicina da Universidade de São Paulo. MÉTODOS: Os testes de processamento auditivo foram aplicados em um grupo de 27 indivíduos, subdivididos em grupos de 11 crianças (7 a 10 anos) e 16 adolescentes (11 a 16 anos) de ambos os sexos, em situação de vulnerabilidade social, e comparado a um grupo controle, formado por 21 crianças, subdivididas em grupos de 10 crianças e 11 adolescentes, pareados por idade, sem queixas. Também se aplicou os PEATE para investigação da integridade da via auditiva. RESULTADOS: Para ambas as faixas etárias, foram encontradas diferenças significantes entre grupos estudo e controle para a maioria dos testes aplicados, sendo que o grupo estudo apresentou desempenho estatisticamente pior do que o controle para todos os testes, exceto para o teste pediatric speech intelligibility. Apenas uma criança apresentou resultado alterado para os PEATE. CONCLUSÕES: Os resultados demonstraram pior desempenho do grupo estudo (crianças e adolescentes) para os testes comportamentais de processamento auditivo, apesar de estes apresentarem integridade da via auditiva em nível de tronco encefálico, demonstrada pela normalidade nos resultados do PEATE.

Sudden bilateral deafness from hyperleukocytosis in chronic myeloid leukemia

Sudden-onset bilateral deafness as a clinical manifestation of hyperleukocytosis in chronic myeloid leukemia (CML) is a rare occurrence. We found only 27 clinical descriptions in 16 published papers. In this work, the authors present a review on deafness in CML and describe a new case with prominent hyperleukocytosis, where the neurological findings suggest slowing of the circulation through small blood vessels in the brainstem as the cause of deafness. The evolution was good after treatment. To our knowledge, this is the second case documented with electrical auditory brainstem-evoked potentials and the first with magnetic resonance imaging. Copyright (C) 2000 S. Karger AG, Basel.

Contrast sensitivity of pattern transient VEP components: contribution from M and P pathways

The purpose of this study was to compare contrast sensitivity estimated from transient visual evoked potentials (VEPs) elicited by achromatic pattern-reversal and pattern-onset/offset modes. The stimuli were 2-cpd, achromatic horizontal gratings presented either as a 1 Hz pattern reversal or a 300 ms onset/700 ms offset stimulus. Contrast thresholds were estimated by linear regression to amplitudes of VEP components vs. the logarithm of the stimulus contrasts, and these regressions were extrapolated to the zero amplitude level. Contrast sensitivity was defined as the inverse of contrast threshold. For pattern reversal, the relation between the P100 amplitude and log of the stimulus contrast was best described by two separate linear regressions. For the N135 component, a single straight line was sufficient. In the case of pattern onset/offset for both the C1 and C2 components, single straight lines described their amplitude vs. log contrast relations in the medium-to-low contrast range. Some saturation was observed for C2 components. The contrast sensitivity estimated from the low-contrast limb of the P100, from the N135, and from the C2 were all similar but higher than those obtained from the high-contrast limb of the P100 and C1 data, which were also similar to each other. With 2 cpd stimuli, a mechanism possibly driven by the M pathway appeared to contribute to the P100 component at medium-to-low contrasts and to the N135 and C2 components at all contrast levels, whereas another mechanism, possibly driven by the P and M pathways, appeared to contribute to the P100 component at high contrast and C1 component at all contrast levels.

Potencial cognitivo em criancas com transtorno do deficit de atencao com hiperatividade

A literatura tem descrito comorbidades entre os sintomas das crianças com Transtorno do Déficit de Atenção com Hiperatividade (TDAH) e as alterações de processamento auditivo e tais sintomas têm sido negligenciados na avaliação e, consequentemente, na reabilitação desses indivíduos.OBJETIVO:Comparar os achados do potencial evocado auditivo de longa latência em crianças com e sem TDAH. MÉTODO:Este estudo é de coorte histórica com corte transversal do tipo caso-controle, no qual participaram 30 crianças, com e sem TDAH na faixa etária de 8 a 12 anos. Foi realizado o potencial evocado auditivo de longa latência em duas varreduras, por meio de tarefas passivas diferindo quanto frequência e duração (MMNf e MMNd) e ativas (P300f e P300d). RESULTADOS:Na comparação entre o desempenho das crianças com e sem TDAH no teste de avaliação eletrofisiológica da audição foram observadas diferenças ao nível de significância para a amplitude de P2 da OE, que foi maior para o grupo com TDAH, e para a amplitude e latência de N2, que se mostraram alteradas no grupo com TDAH. CONCLUSÃO:O presente estudo possibilitou maior conhecimento da via auditiva central das crianças com e sem TDAH quando avaliadas a partir de testes eletrofisiológicos.

Avaliação audiológica comportamental e eletrofisiológica no transtorno do espectro do autismo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relação entre potenciais evocados auditivos de média latência e distúrbio de processamento auditivo: estudo de casos

The Auditory Evoked Middle Latency Response is one of the most promising objective tests in audiology and in revealing brain dysfunction and neuro-audiologic findings. The main advantages of its clinical use are precision and objectivity in evaluating children. This study aimed to analyze the auditory evoked middle latency response in two patients with auditory processing disorder and relate objective and behavioral measures. This case study was conducted in 2 patients (P1 = 12 years, female, P2 = 17 years old, male), both with the absence of sensory abnormalities, neurological and neuropsychiatric disorders. Both were submitted to anamnesis, inspection of the external ear canal, hearing test and evaluation of Auditory Evoked Middle latency Response. There was a significant association between behavioral test and objectives results. In the interview, there were complaints about the difficulty in listening in a noisy environment, sound localization, inattention, and phonological changes in writing and speaking, as confirmed by evaluation of auditory processing and Auditory Evoked Middle Latency Response. Changes were observed in the right decoding process hearing in both cases on the behavioral assessment of auditory processing; auditory evoked potential test middle latency shows that the right contralateral via response was deficient, confirming the difficulties of the patients in the assignment of meaning in acoustic information in a competitive sound condition at right, in both cases. In these cases it was shown the association between the results, but there is a need for further studies with larger sample population to confirm the data.

Frontonasal dysplasia: clinical evaluation on audiological and brainstem electrophysiological profiles

Frontonasal dysplasia (FND) is a rare malformative complex affecting the frontal portion of the face, the eyes and the nose; it may occur singly or associated with other clinical signs. No systematic studies describing hearing in this condition were found. AIM: To evaluate hearing sensitivity and sound stimulus conduction from cochlea to brainstem in patients with clinical signs of FND. METHODS: 21 patients with isolated or syndromic FND were submitted to a clinical (otological/vestibular antecedents and otoscopy) and instrumental (pure tone and speech audiometry, tympanometry and brainstem auditory evoked response) hearing evaluation. DESIGN: A clinical, cross-sectional observational prospective study. RESULTS: Hearing thresholds were normal in 15 (70%) patients, abnormal in 5 (25%), mostly with conductive hearing loss; one patient did not cooperate with testing. The tympanometric curve was type A in 30 (72%) ears, type C in 5 (12%), type As in 4 (9%) and type B in 3 (7%). The auditory brainstem response (ABR) showed no abnormalities. CONCLUSION: Patients with FND showed no abnormalities in the auditory system from cochlea to brainstem in this study. Mild conductive hearing loss found in some is probably related to cleft palate. Further evaluation of hearing pathways at higher levels is recommended.

Potenciais evocados auditivos de longa latência em escolares com transtornos específicos de aprendizagem

Purpose: To study the components of long latency auditory evoked potentials and to compare data from these measures in students with and without learning disabilities. Method: Thirty students, 15 with learning disorder (study group) and 15 typical without learning problems (control group), of both genders, aged 7-14 years, mean age 10 years. They underwent clinical assessment in a clinic belonging to a public university in the state of São Paulo. Following, audiological assessment was performed to determine normal peripheral auditory system and electrophysiological assessment by examining the long latency auditory evoked response. Result: The results showed that there are functional differences between the groups. Increased latency components of long latency auditory evoked potential was observed in the study group compared to the control group. Longer latency values of these components were observed in the left ear when stimulated in the study group. Conclusion: This study contributed to better understanding of the auditory pathway functioning in children with learning disorders and can be a reference for other clinical and experimental studies and thus improve the definition of diagnostic criteria in this population.

Potencial Cognitivo Auditivo e vectoeletronistagmografia em escolares com dislexia e distúrbios de aprendizagem

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Auditory brainstem response in term and preterm infants with neonatal complications: the importance of the sequential evaluation

Introduction Literature data are not conclusive as to the influence of neonatal complications in the maturational process of the auditory system observed by auditory brainstem response (ABR) in infants at term and preterm. Objectives Check the real influence of the neonatal complications in infants by the sequential auditory evaluation. Methods Historical cohort study in a tertiary referral center. A total of 114 neonates met inclusion criteria: treatment at the Universal Neonatal Hearing Screening Program of the local hospital; at least one risk indicator for hearing loss; presence in both evaluations (the first one after hospital discharge from the neonatal unit and the second one at 6 months old); all latencies in ABR and transient otoacoustic emissions present in both ears. Results The complications that most influenced the ABR findings were Apgar scores less than 6 at 5 minutes, gestational age, intensive care unit stay, peri-intraventricular hemorrhage, and mechanical ventilation. Conclusion Sequential auditory evaluation is necessary in premature and term newborns with risk indicators for hearing loss to correctly identify injuries in the auditory pathway.

P300 in individuals with sensorineural hearing loss

INTRODUCTION: Behavioral and electrophysiological auditory evaluations contribute to the understanding of the auditory system and of the process of intervention. OBJECTIVE: To study P300 in subjects with severe or profound sensorineural hearing loss. METHODS: This was a descriptive cross-sectional prospective study. It included 29 individuals of both genders with severe or profound sensorineural hearing loss without other type of disorders, aged 11 to 42 years; all were assessed by behavioral audiological evaluation and auditory evoked potentials. RESULTS: A recording of the P3 wave was obtained in 17 individuals, with a mean latency of 326.97 ms and mean amplitude of 3.76 V. There were significant differences in latency in relation to age and in amplitude according to degree of hearing loss. There was a statistically significant association of the P300 results with the degrees of hearing loss (p = 0.04), with the predominant auditory communication channels (p < 0.0001), and with time of hearing loss. CONCLUSIONS: P300 can be recorded in individuals with severe and profound congenital sensorineural hearing loss; it may contribute to the understanding of cortical development and is a good predictor of the early intervention outcome.

Auditory middle latency response and phonological awareness in students with learning disabilities

Introduction Behavioral tests of auditory processing have been applied in schools and highlight the association between phonological awareness abilities and auditory processing, confirming that low performance on phonological awareness tests may be due to low performance on auditory processing tests. Objective To characterize the auditory middle latency response and the phonological awareness tests and to investigate correlations between responses in a group of children with learning disorders. Methods The study included 25 students with learning disabilities. Phonological awareness and auditory middle latency response were tested with electrodes placed on the left and right hemispheres. The correlation between the measurements was performed using the Spearman rank correlation coefficient. Results There is some correlation between the tests, especially between the Pa component and syllabic awareness, where moderate negative correlation is observed. Conclusion In this study, when phonological awareness subtests were performed, specifically phonemic awareness, the students showed a low score for the age group, although for the objective examination, prolonged Pa latency in the contralateral via was observed. Negative weak to moderate correlation for Pa wave latency was observed, as was positive weak correlation for Na-Pa amplitude.

Auditory steady-state response in the first six months of life

Objective: To characterize the thresholds of the auditory steady-state response that relates to term newborns and infants. Design: The study was cross-sectional using auditory steadystate response assessment, and the real-ear-to-dial difference was measured in the external auditory canal. Study Sample: The study group included 60 newborns and infants between the age of 0 and 6 months. Results: A statistically significant difference was found in the carrier frequency variable for auditory steady-state response thresholds but not in comparison to ages. Furthermore, there is an association between auditory steady-state response thresholds and the real-ear-to-dial difference. Conclusion: The same threshold can be used as a normality reference for this age range, with distinct values for the different carrier frequencies. The influence of external auditory canal amplification should be taken into account.

Estudo normativo e avaliação da influência da idade no potencial evocado auditivo em cães sem raça definida

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)