Blink reflex: comparison of latency measurements in different human races

Abstract

-The blink reflex latencies and cephalometric indexes were analysed in 30 male volunteers from three different races, 10 white, 10 black, and 10 Oriental. Ages ranged from 15 to 59 years, height from 1,60 to 1,80 m, and weight from 60 to 80 kg. Blink reflexes were obtained after unilateral electric stimulation of the supraorbital nerve for quantitative analysis of 3 responses, early ipsilateral (R1), late ipsilateral (R2i) and late contralateral (R2c), obtained from the orbicularis oculi muscle. Cephalometric indexes were calculated by multiplying the ratio between the longer transverse and the longer sagital head diameters by 100. The R1, R2i and R2c latencies were consistent with other published papers revealing no differences between the different racial groups. The mean of the cephalometric indexes of each group were consistent with respective racial characteristics. This study revealed that there are no differences between R1, R2i and R2c latencies in the 3 different studied races.KEY WORDS: blink reflex, races.Reflexo trigêmino-facial: comparação de medidas de latência em diferentes raças Reflexo trigêmino-facial: comparação de medidas de latência em diferentes raças Reflexo trigêmino-facial: comparação de medidas de latência em diferentes raças Reflexo trigêmino-facial: comparação de medidas de latência em diferentes raças Reflexo trigêmino-facial: comparação de medidas de latência em diferentes raças RESUMO -Latências do reflexo trigêmino-facial e índices cefalométricos foram analisados em 30 voluntários adultos normais, de 3 diferentes raças, sendo 10 brancos, 10 negros e 10 orientais. Idades variaram de 15 a 59 anos, alturas de 1,6 a 1,8 m e pesos de 60 a 80 kg. Os reflexos trigêmino-faciais foram obtidos por estimulação elétrica unilateral do nervo supra-orbital e captação nos músculos orbicularis oculi, para análise quantitativa de 3 respostas, ipsolateral precoce (R1), ipsolateral tardia (R2i) e contralateral tardia (R2c). Índices cefalométricos foram obtidos multiplicando-se por 100 a razão entre maior diâmetro transverso e maior diâmetro sagital do crânio. As médias dos índices cefalométricos de cada grupo foram compatíveis com as respectivas características raciais. As respostas R1, R2i e R2c não mostraram diferenças de latências estatisticamente significativas entre as 3 diferentes raças analisadas neste estudo. PALAVRAS-CHAVE: reflexo trigêmino-facial, raças.The blink reflex is a very practical reproducible electrical response, that can be used in comparative clinical studies and experimental models [1][2][3] . At the beginning of XX th century, there was a dispute about the authorship of the original description of the blink reflex 4 . The first report of the eye closure response to forehead percussion was made by Overend, in 1896 6 . The same reflex, obtained in response to percussion of the lateral supra-orbital region was later described by McCarthy 7 , and is still referred to by his name 5 . The blink reflex physiology began to be better understood when Kugelberg performed the fi...

Blink reflex: A practical test to evaluate the trigeminal nerve injury following percutaneous balloon compression for the treatment of trigeminal neuralgia

“…Supraorbital stimulation-induced BR provides an early R1 component with a latency of approximately 10 ms, and a late R2 component with a latency of approximately 30 ms. 32,33 The upper limit of R1 latency was reportedly defined as 13 ms, and ipsilateral R2 latency should not exceed 40 ms. 34,35 In this study, nearly all the patients had normal latency in both R1 pre and R2 pre , except for two patients who were found to have a longer R1 pre (>13 ms) and one patient who had a longer R2 pre latency (>40 ms). The results of R1 pre and R2 pre were almost identical in the symptomatic side and asymptomatic side.…”

Differences in startle reflex and prepulse inhibition in European‐Americans and African‐Americans

“…Genetic effects on ocular muscle morphology or peripheral nerve innervation have been proposed (Swerdlow et al, 2005), although one study found no difference between AA and EA in orbicularis oculi response to electrical stimulation (Kimaid, Resende, Castro, Berzin, & Barreira, 2002). While greater skin pigmentation has long been known to reduce skin conductance (Brown et al, 2006; Korol & Kane, 1978), it is not known whether the skin tone affects measured amplitude of the eyeblink component of the startle reflex in a similar manner.…”

Aspectos neurofisiológicos da musculatura facial visando a reabilitação na paralisia facial

“…Neste estudo, resgatou-se conhecimentos básicos sobre a neurofi siologia do fenômeno de contração até a atrofi a. Denervação e envelhecimento das estruturas das fi bras musculares foram outros aspectos destacados [15][16][17][18][19][20] .…”

“…O resultado, contudo, refere-se à manutenção da atividade neuromuscular mínima, que é o tônus muscular. Portanto, mesmo não existindo correlações clínica, eletromiográfi ca e morfológicas satisfatórias, o estudo detalhado de cada indivíduo com PF é essencial na decisão de eventual reabilitação 17,42,43 .…”