Abstract:O Potencial Evocado Auditivo de Média Latência (PEAML) foi primeiramente descrito por Geisler, Frishkopf, Rosenblith em 1958.1 É caracterizado por uma série de ondas/respostas neuroelétricas gravadas no cérebro através de eletrodos de superfície. Atualmente, tem sido visto como um dos testes eletrofisioló-gicos mais promissores para a avaliação das disfunções e/ou alterações do Sistema Nervoso Auditivo Central. Suas ondas aparecem no intervalo entre 10 e 80 milissegundos (ms) após o início do estímulo auditivo… Show more
“…The variation between the criteria of interpretation of the MLR responses is one of the main difficulties for the validation of normative data and studies with higher level of evidence in the area. The presence of altered results in the absence of complaints or functional changes of hearing indicates the low sensitivity and specificity of the potential (24) and draws attention to the importance of careful interpretation, especially among individuals.…”
Section: Discussionmentioning
confidence: 99%
“…All eight studies followed the positioning pattern of the electrodes indicated by the 10-20 system (28) . The assembly A1/A2/C3/C4/Fpz with the active electrodes in the left (C3) and right (C4) temporaparietal junction, references in the lobes of the left (A1) and right (A2) ears and neutral in the midline polar front position (Fpz) is recommended in the literature (6,7,21,24) and was used in 88% of the analyzed studies. This arrangement allows the response record in the ipsilateral (C3A1 and C4A2) and contralateral (C3A2 and C4A1) derivations, as well as the comparison of results of different hemispheres and stimulated ears, required in neurological diagnosis protocols.…”
dBNA (88%); uso de filtro passa-alta de 10 Hz (50%) e passa-baixa de 200 Hz (75%); montagem dos eletrodos em C3/C4 (ativos) A1/A2 (referências), e Fpz (neutro) (88%); amplitude Na-Pa, como principal parâ-metro de comparação e normalidade; e uso do teste ANOVA (63%) para análise estatística. Nos estudos revisados, a média da latência da onda Pa e da amplitude Na-Pa em crianças e adolescentes normo-ouvintes foi de 32 milissegundos e 1,57 microvolts, respectivamente. Conclusão:Não há consenso quanto aos parâmetros de registro do PEAML em crianças e adolescentes brasileiros. Ainda assim, a média de latência de Pa e amplitude Na-Pa encontrada em crianças e adolescentes brasileiros normo-ouvintes, avaliados nos oito artigos desta revisão, concorda com os parâmetros de normalidade já estabelecidos internacionalmente.
“…The variation between the criteria of interpretation of the MLR responses is one of the main difficulties for the validation of normative data and studies with higher level of evidence in the area. The presence of altered results in the absence of complaints or functional changes of hearing indicates the low sensitivity and specificity of the potential (24) and draws attention to the importance of careful interpretation, especially among individuals.…”
Section: Discussionmentioning
confidence: 99%
“…All eight studies followed the positioning pattern of the electrodes indicated by the 10-20 system (28) . The assembly A1/A2/C3/C4/Fpz with the active electrodes in the left (C3) and right (C4) temporaparietal junction, references in the lobes of the left (A1) and right (A2) ears and neutral in the midline polar front position (Fpz) is recommended in the literature (6,7,21,24) and was used in 88% of the analyzed studies. This arrangement allows the response record in the ipsilateral (C3A1 and C4A2) and contralateral (C3A2 and C4A1) derivations, as well as the comparison of results of different hemispheres and stimulated ears, required in neurological diagnosis protocols.…”
dBNA (88%); uso de filtro passa-alta de 10 Hz (50%) e passa-baixa de 200 Hz (75%); montagem dos eletrodos em C3/C4 (ativos) A1/A2 (referências), e Fpz (neutro) (88%); amplitude Na-Pa, como principal parâ-metro de comparação e normalidade; e uso do teste ANOVA (63%) para análise estatística. Nos estudos revisados, a média da latência da onda Pa e da amplitude Na-Pa em crianças e adolescentes normo-ouvintes foi de 32 milissegundos e 1,57 microvolts, respectivamente. Conclusão:Não há consenso quanto aos parâmetros de registro do PEAML em crianças e adolescentes brasileiros. Ainda assim, a média de latência de Pa e amplitude Na-Pa encontrada em crianças e adolescentes brasileiros normo-ouvintes, avaliados nos oito artigos desta revisão, concorda com os parâmetros de normalidade já estabelecidos internacionalmente.
“…It is generally assumed that these latencies occur between 10 and 80ms after a sound stimulus. [2][3][4][5] Myogenic contamination initially caused much debate about MLR generators, [24][25] which led to many studies until the neurogenic origin of these potentials was demonstrated. 26,28 It is currently known that myogenic responses of the scalp and neck muscles may be elicited by strong acoustic stimuli and/or by difficulties in relaxing the muscles during the test.…”
Section: Discussionmentioning
confidence: 99%
“…1 Auditory evoked potentials may be classified according to their latency; middle latency potentials or responses (MLRs) are waves obtained 10 to 80ms after a sound stimulus. [2][3][4][5] These waves are also known as auditory middle latency responses (AMLR), auditory middle responses (AMR), middle latency auditory evoked potentials (MLAEPs), and middle latency evoked responses (MLER). MLRs are characterized by a polyphasic potential of neuronal origin that occurs sequentially to the auditory brainstem response or evoked potential (ABR).…”
Os potenciais de média latência são potenciais auditivos que ocorrem entre 10ms a 80ms, formados por ondas polifásicas positivas e negativas denominadas de N0, P0, Na, Pa, Nb e Pb. O logon é um estímulo acústico que permite eliciar respostas de média latência ativando regiões específicas da cóclea. Sua vantagem sobre o clique é a possibilidade avaliar as áreas de baixa freqüência (abaixo de 1kHz). OBJETIVO: O objetivo deste trabalho foi verificar a resposta eletrofisiológica das MLR estimulados por logon nas freqüências de 500, 1000 e 2000 Hz. CASUÍSTICA E MÉTODO: Forma de estudo prospectivo e descritivo de uma amostra de 14 voluntárias do sexo feminino, normais dos pontos de vista otológico e audiológico convencional. O estímulo foi monoaural e ipsilateral à derivação de captação dos potenciais (Cz/A1-2). RESULTADOS: O complexo NaPa foi o mais facilmente identificado e esteve presente em 100% dos exames realizados a 2000 Hz e em 96,4% a 500 e 1000 Hz. CONCLUSÕES: As MLR podem se eliciadas pelo logon nas freqüências de 500, 1000 e 2000 Hz; o complexo NaPa foi o evento prevalente das MLR e o estímulo logon a 2000 Hz eliciou maior número de respostas do que as outras freqüências.
“…A study by Schochat et al, (2004) 8 at the cutoff point used in their study, found sensitivity and specificity rates of approximately 70% for subjects with central auditory nervous system injury or auditory processing disorders, and that cutoff points of 30% and 40% (the ear or the electrode effect) are those that have the best balance between sensitivity and specificity 1 .…”
Audi tory 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.
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