Component analysis of pattern evoked occipital potentials in hemianopic patients.

In a group of 33 patients with hemianopia, interhemispherical differences of the visually evoked potentials after pattern stimulation were studied. Both full field stimulation and vertical half field stimulation were applied. The results were not consistent, i.e. interhemispherical differences were not always according to the hemianopia. In general, with hemifield stimulation a better score was obtained. Differences between vascular accidents and tumours as the underlying cause of the hemianopia could not be established. With full-field stimulation and a midline electrode hemianopias could not reliably be detected.