Abstract
Visual evoked potentials from seven horizontally spaced electrodes were recorded from normal subjects and subjects with homonymous hemianopia in response to hemifield pattern flash stimulation. Stimulation produced a large early peak that was positive on the scalp contralateral to the hemifield and negative on the ipsilateral scalp. From computer fitting of the amplitudes versus electrode position, the position of the equivalent source was found to be in the contralateral hemisphere. The horizontal orientation of the dipole source was approximately tangential (parallel) to the occipital scalp surface with negative polarity toward the medial fissure. In normal subjects, visual evoked potential amplitudes at the first peak were positive on the left and negative on the right for right hemifield stimulation. Left hemifield stimulation showed the opposite results. Three patients with homonymous hemianopia showed normal visual evoked potential results from their functional hemifields and nearly flat results from their hemianopic hemifields. The normal visual evoked potentials originated in their intact cortical hemispheres.
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Abbreviations
- CT:
-
computed tomographic
References
Vaughan HG, Katzman R, Taylor J. Alterations of visual evoked response in the presence of homonymous visual defects. Electroencephalogr Clin Neurophysiol 1963; 15: 737–46.
Celesia G, Meredith JT, Pluff K. Perimetry, visual evoked potentials and visual evoked spectrum array in homonymous hemianopia. Electroencephalogr Clin Neurophysiol 1983; 56: 16–30.
Blumhardt LD, Barrett G, Kriss A, Halliday AM. The pattern evoked potential in lesions of the posterior visual pathways. Ann NY Acad Sci 1982; 388: 264–89.
Chain F, Leserve N, Pinel JF, Leblanc M. Spatio-temporal study of visual evoked potentials in patients with homonymous hemianopia. Adv Neurol 1982; 32: 61–70.
Chiappa KH. Evoked potentials in clinical medicine. New York: Raven Press, 1983: 49.
Haimovic IC, Pedley TA. Hemi-field pattern reversal visual evoked potentials, II: Lesions of the chiasm and posterior visual pathways. Electroencephalogr Clin Neurophysiol 1982; 54: 121–31.
Jeffreys DA, Axford JG. Source locations of pattern specific components of human visual evoked potentials, I: Component of striate cortical origin. Exp Brain Res 1972; 16: 1–21.
Biersdorf WR. Cortical evoked responses from stimulation of various regions of the visual field. Doc Ophthalmol Proc Ser 1974; 4: 249–59.
Shagass C, Amadeo M, Roemer PA. Spatial distribution of potentials evoked by half-field pattern reversal and pattern onset stimuli. Electroencephalogr Clin Neurophysiol 1976; 41: 609–22.
Leserve N, Joseph JP. Modifications of the pattern evoked potential (PEP) in relation to the stimulated part of the visual field (clues for the possible origin of each component). Electroencephalogr Clin Neurophysiol 1979; 47: 183–203.
Darcey TM, Ary JP, Fender DH. Spatio-temporal visually evoked scalp potentials in response to partial-field patterned stimulation. Electroencephalogr Clin Neurophysiol 1980; 50: 348–55.
Maier J, Dagnelie G, Spekreijse H, van Dijk BW. Principal components analysis for source localization of VEPs in man. Vision Res 1987; 27: 165–77.
Biersdorf WR. Different scalp localization of pattern onset and reversal visual evoked potentials. Doc Ophthalmol 1987; 66: 313–20.
Barrett G, Blumhardt LD, Halliday AM, Halliday E, Kriss A. A paradox in the lateralization of the visual evoked response. Nature 1976; 261: 253–5.
Frank E. Electric potential produced by two point current sources in a homogeneous conducting sphere. J Appl Physics 1952; 23: 1125–8.
Bell RA, Biersdorf WR, Beck RW. Homonymous hemianopia and pattern onset hemifield visual evoked potentials. Arch Ophthalmol 1989; 107: 1429–30.
Onofrj M, Bodis-Wollner I, Basciana M, Gambi D. Stimulus specificity of visual evoked potential lateralization in humans compared with visual evoked potential lateralization in monkeys and rats. In: Barber C, Blum T, eds. Evoked potentials III. Boston: Butterworths, 1987: 213–20.
Scherg M, von Cramon D. Evoked dipole source potentials of the human auditory cortex. Electroencephalogr Clin Neurophysiol 1986; 65: 344–60.
Ary JP, Klein SA, Fender DH. Location of sources of evoked scalp potentials. Corrections for skull and scalp thickness. Biomed Eng 1981; 28: 447–54.
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Biersdorf, W.R., Bell, R.A. & Beck, R.W. Pattern flash visual evoked potentials in patients with homonymous hemianopia. Doc Ophthalmol 80, 51–61 (1992). https://doi.org/10.1007/BF00161231
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DOI: https://doi.org/10.1007/BF00161231