Low-contrast Pattern-reversal Visual Evoked Potential in Different Spatial Frequencies.
Purpose: To evaluate the pattern-reversal visual evoked potential (PRVEP) in low- contrast, spatial frequencies in time, frequency, and time-frequency domains. Methods: PRVEP was performed in 31 normal eyes, according to the International Society of Electrophysiology of Vision (ISCEV) protocol. Test...
| Publicado en: | Journal of Ophthalmic & Vision Research Vol. 15; no. 3; pp. 362 - 372 |
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| Autores principales: | , , , |
| Formato: | equations & formulas research tables/charts tracings Journal Article |
| Publicado: |
Knowledge E DMCC
2020
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| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=145161950&site=ehost-live header: @attributes: shortDbName: ccm uiTerm: 145161950 longDbName: CINAHL Complete uiTag: AN controlInfo: bkinfo: dissinfo: jinfo: jid: 20082010 AY5S jtl: Journal of Ophthalmic & Vision Research issn: 20082010 maglogo: N pubinfo: dt: 2020 vid: 15 iid: 3 pid: 35682 pub: Knowledge E DMCC artinfo: ui: 145161950 145161950 145161950 10.18502/jovr.v15i3.7455 145161950 ppf: 362 ppct: 10 formats: fmt: @attributes: type: P tig: atl: Low-contrast Pattern-reversal Visual Evoked Potential in Different Spatial Frequencies. aug: au: Hassankarimi, Homa Jafarzadehpur, Ebrahim Mohammadi, Alireza Noori, Seyed Mohammad Reza affil: Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran sug: subj: Evoked Potentials, Visual Physiology Visual Acuity Visual Perception Human Descriptive Statistics Software Signal Processing, Computer Assisted Mathematics ab: Purpose: To evaluate the pattern-reversal visual evoked potential (PRVEP) in low- contrast, spatial frequencies in time, frequency, and time-frequency domains. Methods: PRVEP was performed in 31 normal eyes, according to the International Society of Electrophysiology of Vision (ISCEV) protocol. Test stimuli had checkerboard of 5% contrast with spatial frequencies of 1, 2, and 4 cycles per degree (cpd). For each VEP waveform, the time domain (TD) analysis, Fast Fourier Transform(FFT), and discrete wavelet transform (DWT) were performed using MATLAB software. The VEP component changes as a function of spatial frequency (SF) were compared among time, frequency, and time-frequency dimensions. Results: As a consequence of increased SF, a significant attenuation of the P100 amplitude and prolongation of P100 latency were seen, while there was no significant difference in frequency components. In the wavelet domain, an increase in SF at a contrast level of 5% enhanced DWT coefficients. However, this increase had no meaningful effect on the 7P descriptor. Conclusion: At a low contrast level of 5%, SF-dependent changes in PRVEP parameters can be better identified with the TD and DWT approaches compared to the Fourier approach. However, specific visual processing may be seen with the wavelet transform. pubtype: Academic Journal doctype: equations & formulas research tables/charts tracings Journal Article ougenre: Article language: English refInfo: holdings: @attributes: islocal: N |
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