Effect of Luminance on Visual Evoked Potential Amplitudes in Normal and Disabled Readers

Brannan, Julie R.; Solan, Harold A.; Ficarra, Anthony; Ong, Editha

doi:10.1097/00006324-199804000-00025

Cited by 24 publications

(23 citation statements)

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“…Dyslexic children showed reduced activity compared with control children in a condition that is believed to be strongly influenced by the magnocellular system and thus data would support the hypothesis of abnormalities in the magnocellular pathway. These findings are in accordance to similar results in ERP (Brannan et al, 1998) or functional magnetic resonance imaging (Demb et al, 1997;Eden et al, 1996) data.…”

Section: Motion-onset Paradigmsupporting

confidence: 92%

“…It seems to be associated with reduced phonological awareness and multisensory deficits. One of these lacks has been suggested to result from abnormal visual pathways: Most dyslexic studies (Lovegrove, 1996) indicate a defect in the magnocellular components of the visual processing streams (Livingstone et al, 1991;Brannan et al, 1998). The magnocellular system is, in addition to the parvocellular system, one of the two interactive subsystems for visual processing, arising from cells widely distributed across the retina and projecting to the visual cortex via the ventral lateral geniculate nucleus.…”

Section: Introductionmentioning

confidence: 99%

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Visual information processing in dyslexic children

Scheuerpflug

Plume

Vetter

et al. 2004

Clinical Neurophysiology

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Section: Motion-onset Paradigmsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Visual information processing in dyslexic children

Scheuerpflug

Plume

Vetter

et al. 2004

Clinical Neurophysiology

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“…This result might appear inconsistent with a general finding that a higher luminance level stimulus elicits a larger VEP (e.g., Brannan, Solan, Ficarra, & Ong, 1998;Tobimatsu, KuritaTashima, Nakayama-Hiromatsu, Akazawa, & Kato, 1993). This discrepancy is probably due to the simulation of spectral transmittance under the CS condition.…”

Section: Discussioncontrasting

confidence: 70%

Eye-Fixation Related Potential to Stimuli Simulating the Vision of an Older Adult

Kazai

Abe

Yagi

et al. 2005

PSYCHOLOGIA -An International Journal of Psychological Sciences

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The eye-fixation related potential (EFRP) is a type of visual evoked potential (VEP). In the present study, the effects of simulating the vision of an older adult (Nakano, Higuchi, & Yamamoto, 1996) on the EFRP of young adults were investigated. The EFRP was measured under three conditions: the N condition (original stimulus without any image processing), the CS condition (simulation of a 70-year old person's contrast sensitivity and spectral transmittance), and the C condition (simulation of a 70-year old person's contrast sensitivity). The P65 (positivity with a peak latency of about 65 ms) and N110 (nagativity with a peak latency of about 110 ms) of the EFRP were identified. There was no significant difference between the P65-N110 amplitude of the N condition and that of the CS condition. The peak latency of P65 of the CS condition was longer than those of the other two conditions. These results are in general agreement with previous VEP studies that compared older and young adults. Therefore, these results support the validity of the simulation.

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“…They found an average reduction in amplitude (but not latency) of approximately 35 % under the lower luminance condition as compared with the higher one. However, both the ''average'' (32 cd/m 2 ) and ''local'' (64 cd/m 2 ) luminance levels used in the present investigation were much less extreme and similar to each other, as compared to the two levels used by Brannan et al [30]. Lastly, we performed five VEP repetitions on one experienced subject used in the present study monocularly, using our standard full-field array with and without a 0.3-ND filter, which reduced the stimulus luminance by 50 %.…”

Section: Visual-field Test Condition Mean Amplitude (Microvolts)supporting

confidence: 50%

“…Thus, the average luminance combined over the two half-field would be approximately 32 cd/m 2 , with 0.3 log unit difference. In the only study directly relevant to the present investigation [30], VEP amplitude and latency were assessed under two relatively extreme luminance conditions: 55 cd/m 2 and 0.76 cd/m 2 , a 1.86 log unit difference. They found an average reduction in amplitude (but not latency) of approximately 35 % under the lower luminance condition as compared with the higher one.…”

Section: Visual-field Test Condition Mean Amplitude (Microvolts)mentioning

confidence: 99%

Effect of different stimulus configurations on the visual evoked potential (VEP)

2012

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The purpose of this study was to assess changes in the response profile of the pattern visual evoked potential (VEP) using three stimulus configurations simulating visual-field scotomas: central circular and central blank fields increasing incrementally in diameter from 1° to 15°, hemi-field, and quadrant patterns. Five visually normal adult subjects (ages 22-68 years) were tested binocularly at 1 m for each stimulus configuration on 5 separate days. A checkerboard test pattern (64 × 64 black-and-white checks, 85% contrast, 64 cd/m(2) luminance, 20 s of stimulus duration, 2-Hz temporal frequency) was used. The group mean VEP amplitude increased in a linear manner with increase in the central circular diameter (y = 0.805x + 2.00; r = 0.986) and decrease in central blank field diameter (y = -0.769x + 16.22; r = 0.987). There was no significant change in latency in nearly all cases. The group mean coefficient of variability results indicated that the VEP amplitude was repeatable for the different stimulus configurations. The finding of VEP response linearity for the circular stimulus fields, and repeatability for all stimulus configurations, suggests that the clinician may be able to use the VEP technique with the suggested test patterns as a rapid and simple tool for objective assessment for several types of visual-field defects for a range of abnormal visual conditions and special populations.

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Effect of Luminance on Visual Evoked Potential Amplitudes in Normal and Disabled Readers

Cited by 24 publications

References 0 publications

Visual information processing in dyslexic children

Visual information processing in dyslexic children

Eye-Fixation Related Potential to Stimuli Simulating the Vision of an Older Adult

Effect of different stimulus configurations on the visual evoked potential (VEP)

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