نتایج جستجو برای: evoked visual potential

تعداد نتایج: 1427426  

Journal: :journal of current ophthalmology 0
مرتضی مواسات morteza movassat نیلوفر پیری niloufar piri مهدی نیلی احمدآبادی mehdi nili ahmadabadi

purpose : to demonstrate visual evoked potential (vep) changes in multiple sclerosis (ms) disease methods : a case series study of vep changes in forty-nine patients with definite, probable and possible diagnoses of ms referred to electrophysiology ward from january 2002 to december 2005. pattern vep was done for those with good visual acuity (va), and flash vep was done for those who did not h...

B Varavipour N. Ashjazadeh,

Background: Visual evoked potential (VEP) is regarded as a useful, reliable and non-invasive technique for the diagnosis of lesions in the optic pathway.  This technique was used to investigate visual function in migraine.   Materials and Methods: 53 migraine patients (27 migraine cases with aura and 26 common migraine cases) and 55 controls were prospectively enrolled in this study.  Visual ev...

Journal: :iranian journal of medical sciences 0
n. ashjazadeh electroneurodiagnostic clinic, department of neurology, school of medicine, shiraz university of medical sciences, shiraz, iran b varavipour electroneurodiagnostic clinic, department of neurology, school of medicine, shiraz university of medical sciences, shiraz, iran

background: visual evoked potential (vep) is regarded as a useful, reliable and non-invasive technique for the diagnosis of lesions in the optic pathway.  this technique was used to investigate visual function in migraine.    materials and methods: 53 migraine patients (27 migraine cases with aura and 26 common migraine cases) and 55 controls were prospectively enrolled in this study.  visual e...

and Mohammad Saber Hashemi Sara Hashemi

Introduction: Visual evoked potentials contain certain diagnostic information which have proved to be of importance in the visual systems functional integrity. Due to substantial decrease of amplitude in extra macular stimulation in commonly used pattern VEPs, differentiating normal and abnormal signals can prove to be quite an obstacle. Due to developments of use of machine l...

Journal: :Vision Research 2001
Francesco Di Russo Donatella Spinelli M.Concetta Morrone

This study investigated the effect of attention on the contrast response curves of steady-state visual evoked potentials (VEPs) to counter-phased sinusoidal gratings. The 1 cyc/deg gratings were modulated either in luminance or chromaticity (equiluminant red-green). The luminance grating counter-phased at 9 Hz (to favour activation of the magno-cellular system), and the chromatic grating at 2.5...

Journal: :Vision Research 2002
William Seiple Colleen Clemens Vivienne C Greenstein Karen Holopigian Xian Zhang

To determine the manner in which attention is distributed among numerous locations in the visual space, we used a multifocal recording technique that allowed simultaneous recordings of evoked cortical activity from 12 visual field areas out to 23.6 degrees. We found that multifocal visual evoked potential (mfVEP) amplitude was larger when a region of visual space was attended than when it was n...

Journal: :iranian journal of neurology 0
farzad fatehi department of neurology, shariati hospital, iranian center of neurological research, tehran university of medical sciences, tehran, iran. vahid shaygannejad department of neurology, isfahan university of medical sciences, isfahan, iran lida kiani mehr department of neurology, shariati hospital, iranian center of neurological research, tehran university of medical sciences, tehran, iran alireza dehghani department of ophthalmology, isfahan university of medical sciences, isfahan, iran

background:  optical coherence tomography (oct) is a non-invasive instrument, which can be used to estimate the thickness of the retinal nerve fibre layer (rnfl) and provides an indirect measurement of axonal destruction in multiple sclerosis (ms). the main aim of this study was to find out any correlations between p100 latency in visual evoked potential (vep) and rnfl thickness. methods: the p...

Journal: :Vision Research 1996
Eileen Birch Benno Petrig

Dynamic random dot fusion, stereopsis and stereoacuity were evaluated in 149 healthy, fullterm infants, using both forced-choice preferential looking (FPL) and steady-state visual evoked potential (VEP) protocols. Few infants aged 2-3 months demonstrated fusion or stereopsis in either the FPL or VEP protocol; most infants aged 5 months and older demonstrated fusion and stereopsis in both protoc...

Journal: :Vision Research 2003
Xian Zhang

In this paper, an extended multifocal VEP/ERG paradigm, referred to as the unified multifocal electroretinography and visual evoked potential paradigm (UMEV), is presented. This paradigm allows a simultaneous recording of luminance responses, temporal interactions, spatial interactions and spatial-temporal interactions. Two studies were conducted to demonstrate the capability and validity of th...

Journal: :The International journal of neuroscience 1994
V Kolev C Başar-Eroglu F Aksu E Başar

The present paper complements our investigations on children's and adult's EEGs and evoked potentials elicited by mean of auditory stimulation. We analyzed the spectral characteristics of spontaneously recorded EEGs, visual evoked potentials, and frequency responses of a group of 3-year-old children. The results were compared to the corresponding measurements in adults aged 20-22 years. Our fin...

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