Visual Evoked potential signal processing and analysis for normal and galucomic eyes

2015 ◽  
Vol 8 (2) ◽  
pp. 2106-2121
Author(s):  
Hamed Ibrahem Abdelkader ◽  
Mona Abdelkader ◽  
Mohammed Kabeel ◽  
Malak Alya
Keyword(s):  
Evoked Potentials ◽  
Visual Evoked Potential ◽  
Evoked Potential ◽  
Optic Tract ◽  
Pattern Reversal ◽  
Blue Color ◽  
Check Size ◽  
Retinal Stimulation ◽  
Normal Individuals ◽  
Visual Evoked

Visual evoked potentials (VEPS) are obtained from optic tract by recording the evoked potentials generated by retinal stimulation. The flash VEP (FVEP) is used less frequently than pattern reversal VEP (PRVEP) because; it shows great variation in both latency and amplitude. The present study was undertaken to evaluate the effect of change of wavelength of flash and change of check size on the parameters of visual evoked potential (amplitude and latency) in normal individuals and glaucoma patients. The group of healthy subjects in the age of 20-45 years while the group of glaucoma subjects where  in the age of 25-50 years.  The two groups were exposed to flash VEP with white light and blue color and they also were exposed to checks subtending a visual angles of 15, 30,60 and 120 minutes of arc. The measured data were statistically analyzed and summarized by histograms. The interindividual and intraindividual in latencies and amplitudes for FVEP were assessed using  the coefficient of variation (COV). In conclusion, monochromatic flash VEP was preferred than white as there were minimal inter and intra individual variation of latencies and amplitudes. The most preferred check size in PRVEP was 120' for  the two groups.  

Effect of check size on the pattern reversal visual evoked potential

1991 ◽  
Vol 80 (3) ◽  
pp. 161-166 ◽  
Author(s):  
Shizuka Kurita-Tashima ◽  
Shozo Tobimatsu ◽  
Miyuki Nakayama-Hiromatsu ◽  
Motohiro Kato
Keyword(s):  
Visual Evoked Potential ◽  
Evoked Potential ◽  
Pattern Reversal ◽  
Check Size ◽  
Visual Evoked

scholarly journals Visual acuity evaluated by pattern-reversal visual-evoked potential is affected by check size/visual angle

2012 ◽  
Vol 28 (6) ◽  
pp. 737-745 ◽  
Author(s):  
Xiping Chen ◽  
Qianqian Li ◽  
Xiaoqin Liu ◽  
Li Yang ◽  
Wentao Xia ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Visual Angle ◽  
Visual Evoked Potential ◽  
Evoked Potential ◽  
Pattern Reversal ◽  
Check Size ◽  
Visual Evoked

Primary Presenile Dementia: The Use of the Visual Evoked Potential as a Diagnostic Indicator

1985 ◽  
Vol 147 (5) ◽  
pp. 532-539 ◽  
Author(s):  
Graham F. A. Harding ◽  
Christine E. Wright ◽  
Arnold Orwin
Keyword(s):  
Visual Evoked Potential ◽  
Evoked Potential ◽  
Cortical Atrophy ◽  
Control Group ◽  
Pattern Reversal ◽  
Presenile Dementia ◽  
The Difference ◽  
Pattern Reversal Stimulation ◽  
Diagnostic Indicator ◽  
Visual Evoked

The use of the flash and pattern reversal visual evoked potential (VEP) in the diagnosis of primary presenile dementia was investigated. The results from 20 patients with primary presenile dementia were compared with those from a control group of normals of equivalent age and from a control group of 20 patients with cortical atrophy but no dementia. Presenile dementia caused a slowing of the major positive (P2) component of the VEP to flash stimulation. However, the VEP to pattern reversal stimulation (P100) was of normal latency. The difference between these two latencies characterises this unusual combination of results and is found to be a more specific diagnostic indicator of primary presenile dementia than the EEG or CT scan.

Pattern-Reversal Visual Evoked Potential in Children With Congenital Zika Syndrome

2021 ◽  
Vol 58 (2) ◽  
pp. 78-83
Author(s):  
Luan F. B. Almeida ◽  
Marisa Kattah ◽  
Liana O. Ventura ◽  
Adriana L. Gois ◽  
Camilla Rocha ◽  
...  
Keyword(s):  
Visual Evoked Potential ◽  
Evoked Potential ◽  
Pattern Reversal ◽  
Congenital Zika Syndrome ◽  
Visual Evoked

Pattern-Reversal Visual Evoked Potential on Smart Glasses

2020 ◽  
Vol 24 (1) ◽  
pp. 226-234 ◽  
Author(s):  
Rossana Terracciano ◽  
Alessandro Sanginario ◽  
Simona Barbero ◽  
Davide Putignano ◽  
Lorenzo Canavese ◽  
...  
Keyword(s):  
Visual Evoked Potential ◽  
Evoked Potential ◽  
Pattern Reversal ◽  
Smart Glasses ◽  
Visual Evoked

scholarly journals Cortical Contrast Processing in Retinitis Pigmentosa: Evidence of PVEPs Spatial Functions

2020 ◽  
Vol 10 (4) ◽  
pp. 1010-1019
Author(s):  
Rafael Mancebo-Azor ◽  
José Antonio Sáez-Moreno ◽  
José Manuel Rodríguez-Ferrer
Keyword(s):  
Retinitis Pigmentosa ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Normal Subjects ◽  
Pattern Reversal ◽  
Check Size ◽  
Low Contrast ◽  
Control Subjects ◽  
The Right ◽  
Visual Evoked

Objective: To study the effect of check width size of the stimuli on the amplitude and latency of the P100 component of visual evoked potentials recorded in patients with retinitis pigmentosa (RP). Methods: Pattern reversal visual evoked potentials (PVEPs) were recorded in 16 RP patients and 20 visually normal subjects. Pattern reversal stimuli with five different check widths and 100% of contrast were projected in the right eye of both patients and control subjects. PVEPs induced by stimuli with 78%, 16%, and 6% of contrast were also recorded in 10 of the control subjects. Results: In RP patients, the amplitude of P100 was smaller than controls in all check sized used and the peak P100 amplitude was obtained with a larger check width than in controls. P100 was also delayed in RP patients in all check sizes studied. The P100 amplitude- and latency-check size functions of RP patients were like those found in control subjects with low contrast stimuli of 16% and 6%. Conclusion: The PVEPs spatial functions of RP patients show quantitative and qualitative changes, suggesting disease induced alteration in the neural processing of stimulus contrast.

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