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Stimulus-specific Cortical Visual Evoked Potential Morphological Patterns
Published on: May 12, 2019
Paradoxical robust visual evoked potentials in young patients with cortical blindness
Tamara Wygnanski-Jaffe1, Carole M Panton, J Raymond Buncic
1Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada. twjaffe@hotmail.com
Documenta Ophthalmologica. Advances in Ophthalmology
|June 24, 2009
Summary
Robust pattern visual evoked potentials (VEPs) can be recorded in some children with suspected cortical visual impairment, even when they appear behaviorally blind. This highlights potential discrepancies between VEPs and visually guided behavior in certain cases.
Area of Science:
- Ophthalmology
- Neuroscience
- Pediatrics
Background:
- Cortical visual impairment (CVI) is a leading cause of blindness in children.
- Assessing visual acuity in children with severe visual impairment can be challenging.
- Visual evoked potentials (VEPs) offer an objective measure of visual pathway function.
Purpose of the Study:
- To retrospectively review cases of clinically blind children with robust pattern VEPs.
- To investigate discrepancies between VEP-assessed visual acuity and behavioral measures.
- To identify commonalities in children with CVI exhibiting unexpectedly good VEPs.
Main Methods:
- Retrospective chart review of VEP records from 1990-2000.
- Inclusion criteria: clinically cortically blind children with normal or near-normal VEPs.
- Analysis of VEP data and correlation with behavioral assessments and clinical history.
Main Results:
- Out of 1,113 VEP records, 9 cases (<1%) showed clinically compromised vision but fair to good VEP function.
- The majority (77.5%) of VEP and behavioral acuity measures were concordant.
- Common features in discrepant cases included suspected CVI, seizures, and developmental delay.
Conclusions:
- VEP acuity does not always correlate unequivocally with visually guided behavior.
- Robust VEPs in behaviorally blind children may indicate defects in the visual association cortex, especially with developmental delay and neuroradiographic abnormalities.
- VEPs can reveal residual visual function in some children with severe CVI.
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