background: parkinson's disease (pd) is a neurodegenerative disorder impairing motor, verbal and other abilities. visual evoked potential (vep) assessment is a useful method for analysis of visual system and its function. the present study was designed in order to evaluate whether vep changes are associated with pd. m aterials and methods: in the present study, 100 subjects encompassing 40 pati...

Background: Alzheimer dementia as the most common cause of dementia is a chronic, progressive, irreversible and incurable disease. The second most common cause of dementia after Alzheimer is vascular dementia. One of the systems involved in dementia is the visuospatial system and visual evoked potential (VEP) can be one of the diagnostic methods for this disease. Therefore, the present study ai...

purpose: to evaluate the effect of vertical prism induced stress on binocular visual evoked potentials. methods: using checkerboard stimulus patterns in two spatial frequencies (sfs) of 0.48 cpd as a low sf and 2.18 cpd as a moderate sf reversing with temporal frequency of 4 hz, the effect of increasing visual stress using vertical prisms of 0, 1, 2 and 3 prism diopters on binocular visual evok...

purpose: comparison of the results of visual evoked potential (vep) in time domain and frequency domain between multiple sclerosis (ms) suspected patients and normal indivisuals. method: eleven ms suspected patients with normal visual findings and 20 normal individuals were tested by vep. results were compared between two groups. results: the time domain results showed no significant difference...

purpose : to evaluate the effects of memantine on improving visual function in patients with acute nonarteritic anterior ischemic optic neuropathy (naion) methods : this was a prospective, double masked, randomized, clinical trial. the study involved 47 subjects with unilateral naion of less than 8 weeks duration. eligible patients were randomly allocated to take either memantine tablets (5 mg ...

purpose : evaluation of efficacy of memantine (n-methyl-d-aspartate receptor antagonist) on visual function of patients with acute non-arteritic ischemic optic neuropathy (naion). methods : the study was conducted as interventional case series from november 2005 through november 2006 in farabi eye hospital . twenty-two patients with acute naion of less than 8 weeks duration entered the study. m...

Dynamic random dot correlograms (DRDCs) are binocular stimuli that evoke a percept and a visual evoked potential (VEP) only in case of a mature and functional binocular system. DRDC-VEP is a method extensively used to study cortical binocularity in human infants and nonverbal children. Although the DRDC-VEP was invented 3 decades ago, neither the fundamental parameters, including contrast, of t...

To study components related to parallel processing of information across the visual field, multi-focal pattern reversal visual evoked potentials (VEPs) were recorded using binary m-sequences. Contrast, chromatic, spatial and temporal characteristics of the stimuli were varied in order to favor contributions from either M or P pathways. Responses were decomposed into two additive components whos...

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...

introduction: demyelination is one of the main causes of neurological disability. it is the end product of numerous pathological processes, multiple sclerosis (ms) being the most common cause. more than 70% of the ms patients suffer from optic disturbances. this disease commonly affects the optic pathway, particularly the optic nerves and chiasm. several attempts have been made to produce a sui...