The pattern VEP is frequently abnormal in multiple sclerosis. In this disease the VEP latency is prolonged and the amplitude is reduced. The use of the VEP amplitude in diagnosis is limited because of the large interand intrasubject variability and low signal-to-noise ratio (SNR). Goal of this project is to improve the SNR of VEP’s with alternative averaging procedures, and to investigate wheth...

UNLABELLED The visually evoked potential (VEP) is an electrical signal generated by the occipital cortex in response to light stimulation of the retina. The clinical importance of the VEP consists in the diagnosis of optic nerve diseases and others ocular diseases. For experimental studies of VEP in experimental animals anesthesia is frequently required. Our study sought VEP changes depending o...

OBJECTIVE To study the development of visual acuity in term-born children with cerebral visual impairment and a history of neonatal hypoxic-ischemic encephalopathy. METHODS We studied 19 term-born children, aged 6 months to 6 years, with moderate to severe neonatal hypoxic-ischemic encephalopathy and behaviors indicative of cerebral visual impairment. Longitudinal measures of grating acuity w...

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...

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 hav...

The paper presents the use of visual evoked potentials VEP to objective assessment acuity. Methods using (VEP) rely on changes electrical action generated within cortex. To diagnose degree weakening eyesight a series studies healthy people and visually impaired ones were made. Electrophysiological eye, noninvasive examination allow gives objectivity in acuity what may be very important ophthalm...

Visual function is usually considered to be normal in papilledema. We report previously undescribed abnormalities in the electroretinograms (ERG) and visual evoked potentials (VEP) of two patients with chronic papilledema. The steady-state latencies of the ERG and VEP were calculated using time-difference analysis. The ERG was abnormal under both scotopic (slow) and photopic (fast) flicker cond...

Study of visual evoked potential (VEP) is one of the utilized methods in clinical diagnosis of ophthalmology and neurological disorders. The automatic detection of VEP spectral components is an important tool in the diagnosis of mental activity. This paper presents a novel computational approach using feedforward neural network to identify abnormal subjects from changes in spectral components. ...

PURPOSE The purpose of this study was to compare psychophysical and electrophysiological testings in early optic nerve dysfunction in a group of clinically asymptomatic subjects with suspect ocular hypertension (OHT). METHODS Forty eyes of 40 patients with suspect OHT and asymmetrical horizontal cup/disc ratio (0.2/0.4), 22 eyes of 22 patients with open-angle glaucoma (OAG), and 40 eyes of 40...

BACKGROUND Visual evoked potential (VEP) measures the time taken for visual stimulus to travel from the eye to the occipital cortex. Hypothyroidism affects the central nervous system (CNS) through its role in gene expression, myelin production, axonal transportation, and neurotransmitters. Delay in the conduction of impulses results in abnormal VEP. OBJECTIVE Correlate the electrophysiologica...