Axonal electrovisiogram as an electrophysiological test to evaluate optic nerve and inner retina electrical potentials: findings in normal subjects
Carregando...
Data
2011
Título da Revista
ISSN da Revista
Título de Volume
Editor
Resumo
Purposes: To standardize and validate the technique of axonal electrovisiogram
(AxEvg), defining its normative values and parameters and characterizing its findings
in normal individuals.
Methods: We enrolled 140 normal individuals (280 eyes) divided into seven groups
according to age, each one with 10 males and 10 females. The technique was based
on monocular visual stimulation by a 0 dB intensity bright flash on Ganzfeld bowl at
a presentation rate of 1.4 Hz. Golden cup electrodes were used and electrical waves
were acquired after artifact rejection. For each amplitude and implicit time peak we
calculated the mean, median, pattern deviation, minimum and maximum values and
95% confidence interval.
Results: Monocular visual stimulation with bright flash under mesopic conditions
was the standard technical procedure established. The normal AxEvg waveform
consists of an initial positive wave (named P1, with mean amplitude of 2.0 mV and
mean implicit time peak of 23.1 ms) followed by a negative wave (named N1, with
mean amplitude of -3.9 mV and mean implicit time peak of 41.4 ms). No significant
differences were observed between males and females or between right and left
eyes, but there was an increased P1 and N1 implicit time peaks according to age.
Implicit time characteristics suggest that P1 wave represents an optic nerve electrical
potential and N1 wave represents an inner retinal layers potential.
Conclusions: AxEvg can be considered a pre-chiasmatic visual evoked potential
capable to reliably record the electrical activity of optic nerve and inner retina. The
findings suggest that AxEvg may be useful as an electrophysiological test in the
diagnosis of neuroretinal diseases.
Descrição
Palavras-chave
Electrophysiology, Retina, Electroretinography, Electrodiagnosis, Evoked potentials, visual, Photic stimulation, Optic nerve/physiology, Eletrofisiologia, Eletrorretinografia, Eletrodiagnóstico, Retina, Potenciais evocados visuais, Nervo óptico/fisiologia, Estimulação luminosa
Citação
CELLA, Wener Passarinho et al. Axonal electrovisiogram as an electrophysiological test to evaluate optic nerve and inner retina electrical potentials: findings in normal subjects. Arquivos Brasileiros de Oftalmologia, Rio de Janeiro, v. 74, n. 1, p. 37-43, 2011.