Sensitividade e especificidade do potencial de média latência

Changes in Auditory Evoked Potentials Increase the Chances of Adults Having Central Auditory Processing Disorder

Introduction  Auditory evoked potentials are widely used in clinical practice to complement the assessment of central auditory processing. However, it is necessary to understand whether these potentials are highly accurate, to assist in the diagnosis of auditory processing disorder. Objective  To measure the accuracy of middle and long latency auditory evoked potentials in the diagnosis of auditory processing disorder in adults. Methods  This is a case-control study, formed by a control group of 30 individuals with normal auditory processing assessment, and a case group composed of 43 individuals with altered auditory processing assessment. Their sensitivities, specificities, accuracies, positive and negative predictive values for the diagnosis of alterations were measured and compared between the potentials. Results  The accuracies of the middle and long latency potentials were 51% and 67%, respectively. The P1-N1-P2 and N2-P300 complexes had an accuracy of 57.5% and 58.9%, respectively. The cognitive potential P300 showed an accuracy of 55%. There was no significant result for the middle-latency potential (OR = 1.8; 95% CI: 0.6-5.4, p  > 0.42) and for P300 (OR = 2.63, 95% CI: 0.85-8.43, p  > 0.11). However, the result was significant for the long-latency potential (OR = 6.3; 95% CI: 2-19.6, p  < 0.01). There was a significant result for the P1-N1-P2 complexes (OR = 6.76, 95% CI:1.4-32.5, p  = < 0.010) and N2-P300 (OR = 3.60; 95% CI: 10.16-11.20, p  < 0.039). Conclusion  Individuals with altered long-latency auditory evoked potential are more likely to have auditory processing disorder and, as such, this test can be used as a complementary tool to confirm the diagnosis.

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.

Acquired Central Auditory Processing Disorder in Service Members and Veterans

Purpose A growing body of evidence suggests that military service members and military veterans are at risk for deficits in central auditory processing. Risk factors include exposure to blast, neurotrauma, hazardous noise, and ototoxicants. We overview these risk factors and comorbidities, address implications for clinical assessment and care of central auditory processing deficits in service members and veterans, and specify knowledge gaps that warrant research. Method We reviewed the literature to identify studies of risk factors, assessment, and care of central auditory processing deficits in service members and veterans. We also assessed the current state of the science for knowledge gaps that warrant additional study. This literature review describes key findings relating to military risk factors and clinical considerations for the assessment and care of those exposed. Conclusions Central auditory processing deficits are associated with exposure to known military risk factors. Research is needed to characterize mechanisms, sources of variance, and differential diagnosis in this population. Existing best practices do not explicitly consider confounds faced by military personnel. Assessment and rehabilitation strategies that account for these challenges are needed. Finally, investment is critical to ensure that Veterans Affairs and Department of Defense clinical staff are informed, trained, and equipped to implement effective patient care.

Middle Latency Auditory Evoked Potential (MLAEP) in Workers with and without Tinnitus who are Exposed to Occupational Noise

Background

Tinnitus is an important occupational health concern, but few studies have focused on the central auditory pathways of workers with a history of occupational noise exposure. Thus, we analyzed the central auditory pathways of workers with a history of occupational noise exposure who had normal hearing threshold, and compared middle latency auditory evoked potential in those with and without noise-induced tinnitus.

Material/Methods

Sixty individuals (30 with and 30 without tinnitus) underwent the following procedures: anamnesis, immittance measures, pure-tone air conduction thresholds at all frequencies between 0.25–8 kHz, and middle latency auditory evoked potentials.

Results

Quantitative analysis of latencies and amplitudes of middle latency auditory evoked potential showed no significant differences between the groups with and without tinnitus. In the qualitative analysis, we found that both groups showed increased middle latency auditory evoked potential latencies. The study group had more alterations of the “both” type regarding the Na-Pa amplitude, while the control group had more “electrode effect” alterations, but these alterations were not significantly different when compared to controls.

Conclusions

Individuals with normal hearing with or without tinnitus who are exposed to occupational noise have altered middle latency auditory evoked potential, suggesting impairment of the auditory pathways in cortical and subcortical regions. Although differences did not reach significance, individuals with tinnitus seemed to have more abnormalities in components of the middle latency auditory evoked potential when compared to individuals without tinnitus, suggesting alterations in the generation and transmission of neuroelectrical impulses along the auditory pathway.

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

O Potencial Evocado Auditivo de Média Latência é um teste objetivo promissor na audiologia na pesquisa neuro-diagnóstica das disfunções do sistema auditivo. Tem como vantagens a precisão e objetividade na avaliação e por isso é útil em crianças. O presente estudo teve como objetivo analisar os potenciais evocados auditivos de média latência em dois pacientes com distúrbio de processamento auditivo e relacionar as medidas objetivas e comportamentais. Para tanto foi realizado estudo de caso de dois pacientes (P1= feminino, 12 anos; P2= masculino, 17 anos), ambos com ausência de alterações sensoriais, distúrbios neurológicos, neuropsiquiátricos. Ambos foram submetidos à anamnese, inspeção do meato acústico externo, avaliação audiológica e avaliação do exame de potencial evocado auditivo de média latência. Houve associação significante entre os resultados dos exames comportamentais e objetivos. Na anamnese, houve queixas referentes à dificuldade de escuta em ambiente ruidoso, localização sonora, desatenção, além de trocas fonológicas na escrita e na fala. Foram observadas alterações no processo de decodificação auditiva à direita em ambos os casos na avaliação comportamental do processamento auditivo e no exame de potencial evocado auditivo de média latência a resposta da via contralateral direita foi deficitária, confirmando as dificuldades dos pacientes estudados na atribuição de significado às informações acústicas em condição de competição sonora à direita nos dois casos. Para os casos estudados comprovou-se à associação entre os resultados, porém há necessidade de novos estudos com maior amostra para confirmação dos dados.

Mismatch Negativity (MMN) response studies in elderly subjects

Mismatch Negativity is an endogenous potential which reflects the processing of differences incurred in the acoustic stimulus.

Aim

to characterize MMN responses in elderly subjects and compare with adult subjects.

Materials and methods

prospective study involving 30 subjects, 15 men and 15 women, aged between 60 and 80 years and 11 months. Statistical test: Mann-Whitney. The subjects went through medical evaluation, threshold tonal audiometry, immittance tests, otoacoustic emissions and short and long latency auditory potentials (MMN).

Results

mean latency was 161.33 ms (CZA2) and 148.67 ms (CZA1), in women; of 171 ms (CZA2) and 159.07 ms (CZA1), men. Mean amplitude was −2.753 μV (CZA2) and −2.177 μV (CZA1), women; −1.847 μV (CZA2) and −1.953 μV (CZA1), men. As to the right and left hemispheres, mean latency variable of 166 ms (CZA2) and 153.87 ms (CZA1); for the amplitude variable, mean value of −2.316 μV (CZA2) and −2.065 μV (CZA1).

Conclusion

there is no statistically significant difference between the latency and amplitude when we compared males and females, right and left sides in the elderly and between chronologic ages between adults and elderly subjects.

Efeito de supressão nas vias auditivas: um estudo com os potenciais de média e longa latência

OBJETIVO: avaliar o efeito de supressão no Potencial Evocado Auditivo de Média e Longa Latência em indivíduos sem alterações auditivas, com presença de emissões otoacústicas (EOA) transientes em ambas as orelhas. MÉTODOS: foram avaliados 25 indivíduos (50 orelhas) de 18 a 30 anos de idade, de ambos os sexos, utilizando-se os Potenciais Evocados Auditivos de Média e Longa latência sem e com ruído branco contralateral. Os sujeitos não apresentavam queixa relacionada ao Processamento Auditivo. Foram verificados e comparados os valores numéricos das latências e amplitudes das ondas na avaliação convencional sem ruído e com ruído contralateral. RESULTADOS: a média aritmética da amplitude de resposta na situação com ruído (mascaramento) reduziu em todas as posições (C3/A1, C4/A1, C3/A2 e C4/A2), porém estes achados foram estatisticamente significantes nas posições C4/A1, C3/A2 e C4/A2. CONCLUSÃO: a diminuição da amplitude pode ter relação com o número de sinapses realizadas. O efeito de supressão na amplitude pode estar relacionado à ação do sistema eferente que suprime o número de sinapses neuronais.

A study of logon-evoked middle latency responses in female subjects with normal hearing

The middle latency response (MLR) to an acoustic stimulus occurs between 10 and 80 ms. The waveform is characterized by a series of peaks and troughs labeled N0, P0, Na, Pa, Nb and Pb. Certain acoustic stimuli may excite specific cochlear areas in contrast with clicks, that activate the cochlea between 1000 and 4000 Hz. The logon stimulus activates segmentar areas of the cochlea and has advantages over clicks when assessing low frequency areas of the cochlea (below 1 kHz). Aim: The aim of this paper was to study the MLR electrophysiologic response when activated by logon stimuli at 500, 1000 and 2000 Hz. Method- a prospective and descriptive study. 14 female volunteers had normal otology and conventional audiology results. The stimulus was monoaural and ipsilateral (Cz/A1-2). Results- the NaPa complex was readily identified compared to other complexes and was present in 100% of the tests done at 2000 Hz, and in 96.4% of the tests done at 500 and 1000 Hz. Conclusion-the logon stimulus at 500, 1000 and 2000 Hz elicits MLRs; the NaPa complex was the most frequent event and the 2000 Hz frequency elicited more responses than other frequencies.

Estudo das latências e amplitudes dos potenciais evocados auditivos de média latência em indivíduos audiologicamente normais

Estudo de coorte contemporânea com corte transversal. O Potencial Evocado Auditivo de Média Latência (PEAML) é gerado entre 10 e 80ms e possui múltiplos geradores, com maior contribuição da região tálamo-cortical. O estabelecimento de critérios de normalidade para os valores de latência e amplitude é necessário para uso clínico. OBJETIVOS: Analisar a latência e amplitude do PEAML em indivíduos sem alterações audiológicas, e verificar a confiabilidade da amplitude Pa-Nb. MATERIAL E MÉTODO: Foram coletados os PEAML de 25 indivíduos durante o ano de 2005 e analisados os componentes Na, Pa, Nb para cada orelha testada (A1 e A2), e posicionamento de eletrodo (C3 e C4). RESULTADOS: Observou-se diferença estatisticamente significante entre os valores médios de latência para C3A1 e C4A1 com relação aos componentes Na e Pa, não sendo encontrada esta diferença para o componente Nb e valores médios das amplitudes Na-Pa e Pa-Nb. CONCLUSÃO: Foram estabelecidos os valores das médias e desvios padrão para os parâmetros latência e amplitude dos componentes Na, Pa, Nb, e Na-Pa e Pa-Nb, nas condições C3A1, C4A1, C3A2, C4A2, proporcionando os parâmetros para a análise e interpretação deste potencial.

Middle Latency Response Study of Auditory Evoked Potentials' Amplitudes and Lantencies Audiologically Normal Individuals

Summary

Contemporary cohort cross-sectional study. Introduction: The auditory middle latency response (AMLR) is generated between 10 and 80 ms and has multiple generators, with a greater contribution from the thalamus-cortical pathways. The establishment of normality criteria for latency and amplitude values is necessary for clinical use.

Aim

to analyze the latency and amplitude of the AMLR in individuals without audiological disorders, and verify the reliability of Pa-Nb amplitude.

Materials and Methods

The AMLR of 25 individuals was collected during 2005 and the Na, Pa, Nb components were analyzed for each tested ear (A1 and A2), and electrode positioning (C3 and C4).

Results

A statistically significant difference was noticed among middle latency values for C3A1 and C4A1 regarding components Na and Pa, and no difference for component Nb and mean values for amplitudes Na-Pa and Pa-Nb. Conclusions: We established average and standard deviation values for latency and amplitude parameters for components Na, Pa, Nb and Na-Pa and Pa-Nb, under conditions C3A1, C4A1, C3A2, C4A2, providing a parameter for the analysis and interpretation of this potential.

Comparação dos Potenciais de Latência Média com ou sem estímulo musical

Os Potenciais Auditivos Evocados (PEA) constituem uma fonte rica e complexa de informações sobre as vias do sistema nervoso central e de estruturas ativadas por estimulação auditiva. Devido ao escasso número de trabalhos existentes correlacionando Resposta de Latência Média com diferentes estímulos sonoros, surgiu o interesse em se realizar esse estudo. OBJETIVO: Verificar o Potencial Evocado Auditivo de Média Latência (PEAML) em adultos normo-ouvintes frente à estimulação por clique e com música contralateral. FORMA DE ESTUDO: coorte contemporânea com corte transversal. MÉTODO: Foram realizadas as avaliações de PEAML em 10 sujeitos utilizando cliques na intensidade de 70dBnNA bilateralmente e posteriormente com estímulo musical, sendo que as latências e amplitudes foram medidas. Foi realizada a comparação da amplitude da onda Pa em relação ao eletrodo C3 e C4 e em relação à orelha direita e esquerda na presença e ausência de estímulo musical. RESULTADOS: todos os sujeitos apresentaram PEAML dentro dos limites de normalidade em ambas as orelhas e na avaliação com estímulo musical e clique foi observada uma diminuição das amplitudes na orelha contralateral a apresentação do estímulo musical em todas as posições do eletrodo, embora esta diferença não tenha sido estatisticamente significante. CONCLUSÃO: Sugere-se que o estímulo musical influencia na amplitude do PEAML, uma vez que houve diminuição da amplitude da onda Pa frente a esta estimulação.

Comparing Middle Latency Response With And Without Music

Auditory evoked potentials can be used as a tool to investigate the central nervous system and structures that can be activated by auditory stimulation. There are few studies correlating the Middle Latency Response with different types of auditory stimulation, which led us to undergo this study.

Aim

to verify The Middle Latency Response (MLR) in normal hearing adults when stimulated by clicks and music in the contralateral ear.

Study design

a cross-sectional contemporary cohort.

Method

MLR was carried out on 10 normal hearing subjects using bilateral clicks (70 dB nNA) and music in the contralateral ear. We measured and compared the amplitude and latency of the Pa wave with clicks and clicks and music. We compared the amplitude and latency of the electrodes in sites C3 and C4 for both ears with and without music.

Results

All subjects had MLR within normal limits for both amplitudes and latencies bilaterally. Stimuli with music and clicks revealed a reduction of the amplitude in the contralateral ear with the music stimulus in all electrode sites although this reduction was not statiscally significant.

Conclusion

We conclude that music in the contralateral ear reduces the amplitude of the Pa wave of the MLR.