Electrophysiological Evidences of Visual Field Alterations in Children Exposed to Vigabatrin Early in Life.
We assessed central and peripheral visual field processing in children with epilepsy who were exposed to vigabatrin during infancy.



Steady-state visual evoked potentials and pattern electroretinograms to field-specific radial checkerboards flickering at two cycle frequencies (7.5 and 6 Hz for central and peripheral stimulations, respectively) were recorded from Oz and at the eye in seven school-age children (10.1 ± 3.5 years) exposed to vigabatrin early in life, compared with children early exposed to other antiepileptic drugs (n = 9) and healthy children (n = 8). The stimulation was made of two concentric circles (0 to 5 and 30 to 60 degrees of angle) and presented at four contrast levels (96%, 64%, 32%, and 16%).



Ocular responses were similar in all groups for central but not for the peripheral stimulations, which were significantly lower in the vigabatrin-exposed group at high contrast level. This peripheral retinal response was negatively correlated to vigabatrin exposure duration. Cortical responses to central stimulations, including contrast response functions in the children with epilepsy in both groups, were lower than those in normally developing children.



Alteration of ocular processing was found only in the vigabatrin-exposed children. Central cortical processing, however, was impaired in both epileptic groups, with more pronounced effects in vigabatrin-exposed children. Our study suggests that asymptomatic long-term visual toxicity may still be present at school age, even several years after discontinuation of drug therapy.
Department of Psychology, Université de Montréal, Montreal, Quebec, Canada; Research Center, CHU Sainte-Justine, Montreal, Quebec, Canada.
Noémie
N
Hébert-Lalonde
Research Center, CHU Sainte-Justine, Montreal, Quebec, Canada; Division of Neurology, Department of Pediatrics, Sainte-Justine Hospital, Université de Montréal, Montreal, Quebec, Canada.
Lionel
L
Carmant
Research Center, CHU Sainte-Justine, Montreal, Quebec, Canada; Division of Neurology, Department of Pediatrics, Sainte-Justine Hospital, Université de Montréal, Montreal, Quebec, Canada.
Philippe
P
Major
Research Center, CHU Sainte-Justine, Montreal, Quebec, Canada.
Marie-Sylvie
MS
Roy
Department of Psychology, Université de Montréal, Montreal, Quebec, Canada; Research Center, CHU Sainte-Justine, Montreal, Quebec, Canada.
Maryse
M
Lassonde
Research Center, CHU Sainte-Justine, Montreal, Quebec, Canada; Department of Ophtalmology, Université de Montréal, Montreal, Quebec, Canada; Department of Psychology, Université du Québec à Montréal, Montreal, Quebec, Canada. Electronic address: saint-amour.dave@uqam.ca.
Dave
D
Saint-Amour
D000293:Adolescent; D000927:Anticonvulsants / Q000009:adverse effects* / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004596:Electroretinography; D005074:Evoked Potentials, Visual / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D012160:Retina / Q000187:drug effects / Q000254:growth & development / Q000503:physiopathology; D020888:Vigabatrin / Q000009:adverse effects* / Q000627:therapeutic use; D014786:Vision Disorders / Q000139:chemically induced* / Q000503:physiopathology*; D014785:Vision, Ocular / Q000187:drug effects / Q000502:physiology; D014793:Visual Cortex / Q000187:drug effects / Q000254:growth & development / Q000503:physiopathology; D014794:Visual Fields / Q000187:drug effects* / Q000502:physiology*; D014796:Visual Perception / Q000187:drug effects / Q000502:physiology
D000927:Anticonvulsants; D020888:Vigabatrin
children; electroretinogram; epilepsy; field-specific; vigabatrin; visual evoked potential