The value of electrophysiology results in patients with epilepsy and vigabatrin associated visual field loss

P Hardus*, WM Verduin, TTJM Berendschot, M Kamermans, G Postma, JS Stilma, CWM van Veelen

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    15 Citations (Scopus)

    Abstract

    Purpose: To determine the value of electrophysiological findings in patients with temporal lobe epilepsy and to relate these findings to the amount of concentric contraction of the visual field and the use of vigabatrin,

    Methods: Electro-retinograms and electro-oculograms were done on 30 patients, operated for temporal lobe epilepsy. The patients were divided into three groups: (A) concentric contraction of the visual field associated with a history of vigabatrin medication (15 patients), (B) normal visual field with vigabatrin use (11 patients) and (C) normal visual field without vigabatrin medication (4 patients).

    Results: Electrophysiological abnormalities were found in 50% of the patients in group A. The Arden ratio of the EOG was lowered in 57%. Abnormalities in the ERG were found: b-wave implicit time photopic F was prolonged (50%), b-wave amplitudes scotopic B (53%), C (73%) and G (50%) and photopic H (50%) were diminished. The amount of visual field loss and the total dose of vigabatrin used, showed only slight correlation with the ERG and EGG. The use of vigabatrin during the ERG and EOG recording in group A, gave a higher b-wave amplitude scotopic G in 64% of cases. The a-wave implicit times scotopic G (73%) and photopic G (59%) and H (73%) were shortened in group B.

    Conclusion: EOG was abnormal in 57% in group A. ERG abnormalities could only be found in 50% of group A, mainly in the inner retina. Since also the total dose of vigabatrin and the amount of visual field loss did not really show a correlation with the electrophysiological findings and results of literature are not unanimous, electrophysiology does not appear at present to be a good method to detect patients with, or at risk of vigabatrin associated visual field loss. Regularly performed visual field examination remains the cornerstone in screening.

    Original languageEnglish
    Pages (from-to)169-174
    Number of pages6
    JournalActa ophthalmologica scandinavica
    Volume79
    Issue number2
    Publication statusPublished - Apr-2001

    Keywords

    • electro-oculogram
    • electro-retinogram
    • epilepsy
    • vigabatrin
    • visual field loss
    • TEMPORAL-LOBE EPILEPSY
    • DYSFUNCTION
    • DEFECTS

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