background and objective: vep is a powerful method to study visual system via evaluating evoked potentials. technologic and instrumental restrictions may be the reason of having studies on optical modulation and induction such as color, spatial frequency and contrast. developments of computer software and hardware may lead to an increase in the flexibility of pattern designs. material and meth...

Electrophysiological research has shown clear dysfunction of early visual processing mechanisms in patients with schizophrenia. In particular, the P1 component of the visual evoked potential (VEP) is substantially reduced in amplitude in patients. A novel visual evoked response known as the VESPA (Visual Evoked Spread Spectrum Analysis) was recently described. This response has a notably differ...

PURPOSE The visual evoked potential (VEP) is a frequently used noninvasive measurement of visual function. However, high-amplitude variability has limited its potential for evaluating axonal damage in both laboratory and clinical research. This study was conducted to improve the reliability of VEP amplitude measurement in rats by using electroencephalogram (EEG)-based signal correction. METHO...

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...

In this paper, Principal Component Analysis (PCA) is used to reduce noise from multi-channel Visual Evoked Potential (VEP) signals. PCA is applied to reduce noise from multi-channel VEP signals because VEP signals are more correlated from one channel to another as compared to noise during visual perception. Emulated VEP signals contaminated with noise are used to show the noise reduction abilit...

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 evoked response testing has been one of the most exciting clinical tools to be developed from neurophysiologic research in recent years and has provided us with an objective method of identifying abnormalities of the afferent visual pathways. Investigation were carried out to see whether the head circumference influence the pattern reversal visual evoked potential (PRVEP) parameters. The...

the objective of this study is development of driver’s sleepiness using visually evoked potentials (vep). vep computed from eeg signals from the visual cortex. we use the steady state veps (ssveps) that are one of the most important eeg signals used in human computer interface systems. ssvep is a response to visual stimuli presented. we present a classification method to discriminate between cl...

OBJECTIVE Patients with Parkinson's disease (PD) may have sensory dysfunction, and it can be more easily demonstrated through electrophysiologic testing. We aimed to explore whether the impairment of brainstem visual and auditory passageway exists in PD patients using visual evoked potential (VEP) and brainstem auditory evoked potential (BAEP) examinations. METHODS Forty-two PD cases and thir...

INTRODUCTION T he neurological electrical activity set off by a light stimulus is known as visual evoked potential (VEP) and is obtained by skin electrodes placed over the occipital cortex after repeated retinal stimulation. The VEP reflects the optic pathways functionality from the retina until the occipital visual cortex, and the measurable electric wavelets generated by bright flashing light...