Ear and electrode effects reduce within-group variability in middle latency response amplitude measures

Study of aged central auditory function using the auditory middle latency response

OBJECTIVE

Investigate the auditory function of the elderly using the middle latency potentials.

METHODOLOGY

Group 1 (G1): 20 healthy individuals of both genders, older than 60 years, without hearing loss. Group 2 (G2): 20 healthy individuals of both sexes, older than 60 years, with hearing loss in frequencies from 4 to 8 kHz. Potential recording was performed with unilateral and bilateral stimulation and the Binaural Interaction Component was calculated.

RESULTS

Na latency in C3A1 was greater in the stimulation of the right ear in G2 and the amplitude of Na-Pa was greater in the stimulation of the right ear and recording in C3A1 in G1. The latency of the Pa component was higher in the stimulation of the right ear recorded in C4A2. The Pb component in G2 by bilateral stimulation and recorded in C4A2 had higher latency. The first and second negative and positive peaks presented greater amplitude in G1. In C3A1, the 1^st negative peak was more negative in G1 and the 2^nd positive peak showed greater amplitude in C4A2 in both groups.

CONCLUSION

The transmission of auditory information to the primary auditory cortex is impaired with aging, especially in unilateral stimulation, reinforced by losses in elderly people with peripheral hearing loss, such as in the binaural interaction at the cortical and subcortical levels. Thus, the AMLR has shown to be a sensitive examination to investigate neuroauditory disorders in the elderly, especially related to high-frequency hearing loss and primary auditory cortex dysfunctions caused by the aging process.

Standardization of Latency and Amplitude Values of Short, Middle and Long Latency Auditory Evoked Potentials in Adults

Introduction  Auditory processing refers to the efficiency and effectiveness with which the central auditory nervous system uses auditory information. Middle- and long-latency auditory evoked potentials are objective electrophysiological tests that can complement the diagnosis of alterations involving central auditory processing. Objective  To standardize latency and amplitude values for short-, middle-, and long-latency auditory evoked potentials in adults with normal hearing thresholds. Methods  This is a cross-sectional study. Thirty-three adults with normal hearing thresholds, without hearing complaints, and with normal central auditory processing were evaluated. All underwent basic audiological evaluation, central auditory processing assessment, and short-, middle-, and long-latency auditory evoked potentials. Results  Absolute latency and interpeak values for middle- and long-latency auditory evoked potentials were lower than internationally suggested. However, for the brainstem auditory evoked potential, the means were within the range considered as normal, as suggested in the equipment. Conclusion  The present study provided measurements of normal latencies and amplitudes for short-, middle-, and long-latency auditory evoked potentials in adults.

Frequency-Following Response and Auditory Middle Latency Response: an analysis of central auditory processing in young adults

ABSTRACT Purpose: to compare the latency and amplitude of the Frequency-Following Response and the Auditory Middle Latency Response in typical individuals and those with altered auditory abilities, as well as to investigate the sensitivity and specificity of both assessments in relation to central auditory processing. Methods: 32 individuals of both sexes were distributed into Group 1 (without altered auditory abilities) and Group 2 (with altered auditory abilities). The groups were divided according to behavioral tests of central auditory processing. Individuals in both groups underwent auditory evoked potentials. Student’s t-test was used for analysis, considering a 5% significance. Results: in Group 2, V and A had higher latency and lower amplitude and slope. Group 2 also had lower Na and Pa amplitudes in waves A1C3 and A2C3. The Frequency-Following Response showed 93% sensitivity and specificity, while the Auditory Middle Latency Response showed 87% sensitivity and 93% specificity. Conclusion: the individuals presented with altered hearing abilities showed higher latency and lower response amplitude in the Frequency Following Response and Auditory Middle Latency Response compared to typical individuals. The Frequency- Following Response showed a better balance of sensitivity and specificity.

Frequency-Following Response e Potencial Evocado Auditivo de Média Latência: uma análise frente ao processamento auditivo central de jovens adultos

RESUMO Objetivo: comparar a latência e a amplitude do Frequency-Following Response e do Potencial Evocado Auditivo de Média Latência em indivíduos típicos e com alterações das habilidades auditivas, assim como investigar a sensibilidade e especificidade de ambas as avaliações frente ao processamento auditivo central. Métodos: 32 indivíduos de ambos os sexos foram distribuídos em Grupo 1 (sem alterações de habilidades auditivas) e Grupo 2 (com alteração em habilidades auditivas). Os grupos foram divididos de acordo com testes comportamentais do processamento auditivo central. Os indivíduos de ambos os grupos foram submetidos aos potenciais evocados auditivos. O teste T de Student foi utilizado para a análise, considerando 5% de significância. Resultados: no Grupo 2, V e A apresentaram maior latência e menor amplitude e slope. O Grupo 2 também apresentou menores amplitudes de Na e Pa nas ondas A1C3 e A2C3. O Frequency-Following Response apresentou 93% de sensibilidade e especificidade, enquanto o Potencial Evocado Auditivo de Média Latência apresentou 87% de sensibilidade e 93% de especificidade. Conclusão: os indivíduos com alteração das habilidades auditivas apresentaram maior latência e menor amplitude de resposta no Frequency Following Response e Potencial Evocado Auditivo de Média Latência em relação aos indivíduos típicos. O Frequency-Following Response apresentou melhor equilíbrio de sensibilidade e especificidade.

Electrophysiological characteristics in children with listening difficulties, with or without auditory processing disorder

Objective: To determine if the auditory middle latency responses (AMLR), auditory late latency response (ALLR) and auditory P300 were sensitive to auditory processing disorder (APD) and listening difficulties in children, and further to elucidate mechanisms regarding level of neurobiological problems in the central auditory nervous system. Design: Three-group, repeated measure design. Study sample: Forty-six children aged 8-14 years were divided into three groups: children with reported listening difficulties fulfilling APD diagnostic criteria, children with reported listening difficulties not fulfilling APD diagnostic criteria and normally hearing children. Results: AMLR Na latency and P300 latency and amplitude were sensitive to listening difficulties. No other auditory evoked potential (AEP) measures were sensitive to listening difficulties, and no AEP measures were sensitive to APD only. Moderate correlations were observed between P300 latency and amplitude and the behavioural AP measures of competing words, frequency patterns, duration patterns and dichotic digits. Conclusions: Impaired thalamo-cortical (bottom up) and neurocognitive function (top-down) may contribute to difficulties discriminating speech and non-speech sounds. Cognitive processes involved in conscious recognition, attention and discrimination of the acoustic characteristics of the stimuli could contribute to listening difficulties in general, and to APD in particular.

Working Memory and Auditory Processing in School-Age Children

Purpose

Our goal is to present the relationships between working memory (WM) and auditory processing abilities in school-age children.

Review and Discussion

We begin with an overview of auditory processing, the conceptualization of auditory processing disorder, and the assessment of auditory processing abilities in children. Next, we describe a model of WM and a model of auditory processing followed by their comparison. Evidence for the relationships between WM and auditory processing abilities in school-age children follows. Specifically, we present evidence for the association (or lack thereof) between WM/attention and auditory processing test performance.

Clinical Implications

In conclusion, we describe a new framework for understanding auditory processing abilities in children based on integrated evidence from cognitive science, hearing science, and language science. We also discuss clinical implications in children that could inform future research.

Uso do potencial evocado auditivo de média latência em populações infantis: uma revisão integrativa

RESUMO Este estudo teve como objetivo investigar na literatura a utilidade do Potencial evocado auditivo de média latência na população infantil para o estudo do sistema auditivo em seus processos normais e desviantes. A revisão integrativa da literatura científica consistiu na busca de estudos utilizando as bases de dados: PubMed, Scopus e Scielo. Como descritores para a pesquisa foram utilizados os termos: "auditory middle latency response" "auditory middle latency potential" , "children", "child", "childhood", "maturation' e "development". Os estudos eram artigos completos, cujos participantes foram crianças, submetidas ao exame de Potencial evocado auditivo de média latência. A análise dos estudos individualmente verificou aspectos relacionados ao objetivo da pesquisa, a metodologia utilizada e a conclusão de cada estudo. Foram selecionados e lidos na íntegra um total de 11 estudos da base bibliográfica PubMed, oito estudos da Scopus e dois estudos da Scielo. Do total de 21 artigos, seis deles foram realizados com crianças saudáveis, quatro examinaram os componentes desse potencial em crianças com distúrbio de linguagem ou distúrbio específico de linguagem, quatro estudos avaliaram crianças usuárias de implante coclear, e sete crianças com outras alterações. Esta revisão integrativa mostrou a importância da investigação dos potenciais evocados auditivos de média latência em crianças. Tal avaliação vem permitindo um diagnóstico mais precoce e preciso de pacientes com alterações de linguagem, fala ou de aprendizado e de distúrbios do processamento auditivo além do monitoramento de evolução terapêutica.

Central auditory processing disorders in children and adults

Central auditory processing disorders (CAPD) can affect children and adults of all ages due to a wide variety of causes. CAPD is a neurobiologic deficit in the central auditory nervous system (CANS) that affects those mechanisms that underlie fundamental auditory perception, including localization and lateralization; discrimination of speech and non-speech sounds; auditory pattern recognition; temporal aspects of audition, including integration, resolution, ordering, and masking; and auditory performance with competing and/or degraded acoustic signals (American Speech-Language-Hearing Association, 2005a, b). Although it is recognized that central auditory dysfunction may coexist with other disorders, CAPD is conceptualized as a sensory-based auditory disorder. Administration of behavioral and/or electrophysiologic audiologic tests that have been shown to be sensitive and specific to dysfunction of the CANS is critical for a proper diagnosis of CAPD, in addition to assessments and collaboration with a multidisciplinary team. Intervention recommendations for CAPD diagnosis are based on the demonstrated auditory processing deficits and related listening and related complaints. This chapter provides an overview of current definitions and conceptualizations, methods of diagnosis of, and intervention for, CAPD. The chapter culminates with a case study illustrating pre- and posttreatment behavioral and electrophysiologic diagnostic findings.