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Visual evoked potentials in the evaluation of "cortical blindness" in children
Insights
Visual evoked responses (VERs) are not always accurate for diagnosing cortical blindness in children. Abnormal VERs can occur in children with normal vision, suggesting limitations in this diagnostic method.
Area of Science:
- Neuroscience
- Ophthalmology
- Pediatrics
Background:
- Cortical blindness in children presents diagnostic challenges.
- Visual evoked responses (VERs) are a common neurophysiological tool used in assessing visual pathway function.
Purpose of the Study:
- To evaluate the diagnostic accuracy of VERs in identifying cortical blindness in children.
- To compare VERs between children with and without cortical blindness.
Main Methods:
- Recorded VERs to brief light flashes from the occipital regions of 30 children diagnosed with cortical blindness and 31 neurologically impaired children without blindness.
- Analyzed VERs for amplitude, number of peaks, and morphology using a standardized method.
Main Results:
- All recorded VERs exhibited some degree of abnormality.
- No significant differences in VER abnormalities were found between the "cortically blind" group and the control group.
- Only one child with cortical blindness showed no VER response.
Conclusions:
- VERs may not be a definitive diagnostic tool for cortical blindness in children.
- Abnormal VERs can be present in children with normal vision, indicating potential limitations in diagnosing visual impairment solely through this method.
Abstract:
Visual evoked responses (VERs) to brief light flashes were recorded from occipital regions in a group of 30 "cortically blind" children aged 4 months to 15 years and were compared with those of 31 children of similar age range who had the same type of central nervous system diseases but without signs or symptoms of blindness. The VERs were analyzed for amplitude, number of peaks, and morphology, following a method used previously by other authors. All the responses had some degree of abnormality, but there were no significant differences between the two groups. The findings suggest that recording of VERs is not always an accurate method for diagnosis of cortical blindness in children since the presence of abnormal responses is not incompatible with normal vision. Only 1 patient with coritcal blindness showed no response.