Effects of sweep VEP parameters on visual acuity and contrast thresholds in children and adults

Almoqbel, Fahad; Yadav, Naveen; Leat, Susan J.; Head, L. M.; Irving, Elizabeth L.

doi:10.1007/s00417-010-1469-8

Cited by 18 publications

(39 citation statements)

References 36 publications

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“…However, since the acuity is extrapolated from the higher spatial frequencies, this decreased signal magnitude for the lower spatial frequencies does not affect the results. Similar observations have been made by Tyler et al [29] and Almoqbel et al [30]. Different stimulus screen sizes will have an additional affect if sVEP comparisons are made in infants or children.…”

Section: Discussionsupporting

confidence: 77%

Comparing enfant and PowerDiva sweep visual evoked potential (sVEP) acuity estimates

2014

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Section: Discussionsupporting

confidence: 77%

Comparing enfant and PowerDiva sweep visual evoked potential (sVEP) acuity estimates

2014

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“…One of the only studies addressing this issue compared visual acuity and contrast thresholds obtained for two electrode placements of five electrodes in the occipital region, with a 2-to 3-cm shift of the electrodes between the two placements. 18 This study showed no significant effect of electrode placement on visual acuity and contrast thresholds. However, even though the authors compared these two placements, they did not compare electrodes individually.…”

mentioning

confidence: 87%

“…These steps were defined as the epochs either above or below the average thresholds found in previous comparable experiments. 4,18,20,25,30,35 More precisely, for visual acuity, this corresponded to the nine steps with spatial frequency from 2.7 to 9.7 cpd for group E, and to the seven steps from 3.8 to 9.4 cpd for group AA. For contrast sensitivity, this corresponded to the nine steps with contrast from 1.5% to 16%.…”

Section: Eeg Analysismentioning

confidence: 99%

Rapid Objective Assessment of Contrast Sensitivity and Visual Acuity With Sweep Visual Evoked Potentials and an Extended Electrode Array

Hemptinne¹,

Liu‐Shuang²,

Yüksel

et al. 2018

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. Sweep visual evoked potentials (sVEPs) provide an implicit, objective, and sensitive evaluation of low-level visual functions such as visual acuity and contrast sensitivity. For practical and traditional reasons, sVEPs in ophthalmologic examinations have usually been recorded over a single or a limited number of electrodes over the medial occipital region. Here we examined whether a higher density of recording electrodes improves the estimation of individual low-level visual thresholds with sVEPS, and to which extent such testing could be streamlined for clinical application. METHODS.To this end, we tested contrast sensitivity and visual acuity in 26 healthy adult volunteers with a 68-electrode electroencephalogram (EEG) system. RESULTS.While the most sensitive electrophysiologic response was found at the traditional medial occipital electrode Oz in a small majority of individuals, it was found at neighboring electrodes for the remaining participants. At the group level, lower spatial frequencies were also associated with right lateralized responses. More generally, visual function was evaluated more sensitively based on EEG recorded at the most sensitive electrode defined individually for each participant. Our data suggest that recording over seven posterior electrodes while limiting the testing session to less than 15 minutes ensures a sensitive and consistent estimation of acuity and contrast sensitivity threshold estimates in every individual.CONCLUSIONS. The present study shows that sampling from a larger number of posterior scalp electrodes is relevant to optimize visual function assessment and could be achieved efficiently in the time-constrained clinical setting.

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“…The VEP has long been used as a clinical tool to determine if the primary afferent visual pathway is intact, as well as to assess an individual’s visual acuity [2,3,4]. Using high-contrast pattern-reversal stimuli, which consist of a black-and-white checkerboard pattern changing phase with constant mean luminance, the pattern VEP produces low variability of waveform both within an individual subject and across subjects [1].…”

Section: Introductionmentioning

confidence: 99%

Objective assessment of the human visual attentional state

et al. 2012

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Primary objective The purpose of this study was to develop an objective way to assess human visual attention using the alpha band component of the visual-evoked potential (VEP). Design and methods Six different attentional conditions were tested: eyes-open, eyes-closed, eyes-closed with backwards number counting, and three rapid serial visual presentation (RSVP) tasks. 18 visually-normal, young-adult subjects (ages 21 to 28 years) were tested binocularly at 1 meter for each condition on two separate days. The Diopsys™ NOVA-TR system was used to obtain the visual-evoked potential (VEP) and extracted alpha-wave and its related power spectrum. Additionally, the Visual Search and Attention Test (VSAT) was administered as a subjective measure of visual attention. Results Subjects exhibited significant decreases in power in the alpha band when comparing the eyes-closed to the eyes-open conditions, with power in the eyes-closed condition being, on average, twice as large. The response from the other four conditions did not reflect the differential attentional demands. The ratio of the power in the eyes-closed condition to the eyes open condition in the lower alpha frequencies (8–10 Hz) was found to be significantly correlated to the group’s performance on the VSAT, especially the 10 Hz component. Conclusions An individual’s ability to attenuate their alpha-component during visual processing may be a predictor of their visual attentional state. These findings solidify the role of the VEP alpha subcomponent as an objective electrophysiological correlate of visual attention, which may be useful in the diagnosis and treatment of human visual-attention disorders in the future.

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Effects of sweep VEP parameters on visual acuity and contrast thresholds in children and adults

Cited by 18 publications

References 36 publications

Comparing enfant and PowerDiva sweep visual evoked potential (sVEP) acuity estimates

Comparing enfant and PowerDiva sweep visual evoked potential (sVEP) acuity estimates

Rapid Objective Assessment of Contrast Sensitivity and Visual Acuity With Sweep Visual Evoked Potentials and an Extended Electrode Array

Objective assessment of the human visual attentional state

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