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Variability of laser-evoked potentials: attention, arousal and lateralized differences.
Beydoun, A; Morrow, T J; Shen, J F; Casey, K L.
Afiliação
  • Beydoun A; Department of Neurology, University of Michigan Medical School, Ann Arbor.
Article em En | MEDLINE | ID: mdl-7684966
ABSTRACT
We recorded laser-evoked potentials (LEPs) from 20 normal subjects by stimulating the skin with pulses from an infrared CO2 laser. The conduction velocity of the peripheral afferent fibers mediating the LEPs averaged 14.9 m/sec. The amplitude of the LEP components correlated significantly with perceived stimulus intensity. During repetitive constant intensity stimulation, the peak-to-peak LEP amplitude decreased 38% during a distraction task and 42% during drowsiness and was absent during stage 2 sleep, indicating a modulation of responsiveness to laser stimulation during distraction and decreased states of arousal. Normative data revealed considerable intersubject variability in LEP latencies and amplitudes. Analysis of intrasubject lateralized (side-to-side) differences revealed that the relative peak-to-peak amplitude was less variable than that of the N or P components. For clinical applications using 3 S.D.s to define the normal range, a lateral interpeak amplitude difference greater than 28% would suggest focal or lateralized sensory abnormality in an individual patient. Vigilance and attentiveness to the stimuli should be monitored during the acquisition of LEPs.
Assuntos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Nível de Alerta / Atenção / Encéfalo / Potenciais Evocados / Lasers / Lateralidade Funcional Tipo de estudo: Diagnostic_studies Limite: Adult / Female / Humans / Male Idioma: En Revista: Electroencephalogr Clin Neurophysiol Ano de publicação: 1993 Tipo de documento: Article
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Nível de Alerta / Atenção / Encéfalo / Potenciais Evocados / Lasers / Lateralidade Funcional Tipo de estudo: Diagnostic_studies Limite: Adult / Female / Humans / Male Idioma: En Revista: Electroencephalogr Clin Neurophysiol Ano de publicação: 1993 Tipo de documento: Article