Potenciais evocados auditivos do tronco encefálico por condução óssea em indivíduos normais

Abstract

Background: bone conduction auditory brainstem responses (ABR) in normal hearing individuals. Aim: to evaluate the clinical applicability of bone conduction ABR, characterizing normality and determining an assessment protocol. Method: participants of this study were 22 individuals with normal hearing (20dB NA), with ages between 20 and 30 years, 14 female and 8 male. All individuals were assessed using air and bone (vibrator positioned on the forehead and mastoid) conduction ABR. EP25 equipment, Interacoustic; 3A insertion phone; B-71 bone vibrator; click stimulus. Results: it was possible to evaluate the bone conduction ABR in all individuals. The results demonstrate that the electrophysiological threshold obtained when the vibrator was positioned on the forehead (32.69 ± 5.63 and 32.5 ± 7.07dB nHL) was higher than that obtained when the vibrator was positioned on the mastoid (25.00 ± 7.33 and 30.00 ± 5.34dB nHL) for both genders respectively. For this reason the vibrator was positioned on the mastoid. The electrophysiological threshold obtained by bone conduction was higher than that obtained by air conduction for both genders and also when all individuals were grouped together. Thus it is necessary to use a correction factor, according to the results, of 10dB nHL. The latency-intensity values of the V wave in the ipsilateral and contralateral recordings differed statistically according to gender, and should be considered separately. The value of 26.81 ± 6.99dB nHL was adopted as being the normal threshold for bone conduction ABR. Conclusion: it is possible to evaluate bone conduction ABR in the clinical environment. These results, when considered along with the air conduction ABR, increase the chances of a more precise diagnosis regarding the type of hearing loss. Key Words: Evoked potentials; Auditory; Brain Stem; Bone Conduction. ResumoTema: potenciais evocados auditivos do tronco encefálico (PEATEs) por condução óssea. Objetivo: avaliar a aplicabilidade clínica da pesquisa dos PEATEs por condução óssea, caracterizando a normalidade e determinando um protocolo de avaliação. Método: participaram deste estudo 22 indivíduos, na faixa etária entre 20 e 30 anos, sendo 14 do sexo feminino e 8 do sexo masculino, com audição normal (20dB NA). Os indivíduos foram avaliados por meio dos PEATEs por condução aérea e óssea (vibrador na fronte e mastóide). Equipamento EP25, Interacoustic; fone de inserção 3A; vibrador ósseo B-71; estímulo click. Resultados: foi possível realizar a pesquisa dos PEATEs por condução óssea em todos os indivíduos avaliados. Os resultados demonstraram que o limiar eletrofisiológico obtido com o vibrador na fronte (32,69 ± 5,63 e 32,5 ± 7,07dB nHL) foi maior do que quando o vibrador foi posicionado na mastóide (25,00 ±7,33 e 30,00 ± 5,34dB nHL), tanto para o sexo feminino quanto para o sexo masculino, respectivamente. Assim, optou-se pelo posicionamento do vibrador na mastóide. O limiar eletrofisiológico obtido por condução óssea foi maior que o limiar por condução áerea, com diferença ...

Update on Bone-Conduction Auditory Brainstem Responses: A Review

“…Stuart, et al [ 7 ] reported on BC ABR for three different placements in temporal bone and found that the posterior and supero-posterior placements could generate clearer waveforms with shortened latency than in the superior placement. De Freitas, et al [ 16 ] reported that oscillator placement on the mastoid could estimate a lower level of thresholds than on the forehead. The density and thickness of the cranial bones and fontanelles, which comprises any soft membranous gap between the cranial bones that make up the calvaria of a fetus or an infant, are factors that can affect oscillator placement for BC ABR in adults and infants [ 7 , 8 ].…”

Potencial evocado auditivo de tronco encefálico por condução óssea: uma revisão integrativa

“…Table 2 shows the distribution of literary production according to the type of transducer used, the position of the bone vibrator and the pressure used. The most widely used transducers to capture the air-conducted stimulus were the supra-aural headphones, such as the TDH-39 8,[13][14][15]18,19,33,35 . The transducer for the bone-conducted stimulus …”

“…Intensities ranged between 100 dB Nan and 10 dB Nan for the click stimulus, 70 dB Nan and dB Nan for the tone burst and 80 dB Nan and 10 dB Nan for the tone pip. Most studies used alternate polarity with different presentation rates, the most widely adopted being 57.7/s 26,29,30,31,36,38 , followed by 27.7/s 6,8,17 and 21.1/s 8,17,26 .…”

“…This potential is obtained between 0 and 10 milliseconds (ms) after presentation of the acoustic stimulus, and its presence or not enables assessment of the integrity of the auditory pathway to the brainstem 1,2 . Auditory Evoked Potential (AEP) exams are classified according to latency, anatomic origin, relationship of malformation of the auricular pavilion and/or the middle ear 8 . Even though bone-conducted BAEP has been routinely used in clinical practice for years, there are few studies regarding standardization and the procedures used to obtain responses with tone-burst stimuli in newborns, especially when this stimulus is presented by bone conduction at frequencies of 1000 and 4000 Hz, making it difficult to classify the alteration [9][10][11] .…”

Editorial

“…Estudo dos potenciais evocados auditivos do tronco encefálico por condução óssea em 22 adultos com audição normal foi realizado por Freitas et al (2006). Os resultados da pesquisa indicam que o PEATE por condução óssea contribui de forma importante para a precisão diagnóstica do tipo de perda auditiva.…”