Delayed visual evoked potentials are independent of pattern orientation in macular disease

Bódis-Wollner, Iván; Feldman, Robert G.; Guillory, Samuel L.; Mylin, L.

doi:10.1016/0168-5597(87)90024-4

Cited by 18 publications

(10 citation statements)

References 17 publications

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“…This finding implies cortical pathology because the receptive field of retinal cells is circular or oval (86) and therefore these cells do not have a significant response preference for one orientation or another. The VEPs of patients with macular degeneration are slowed but are not sensitive to sine wave grating orientation (87), further supporting the hypothesis that cortical pathology underlies the sensitivity to orientation, as the retina is the site of the lesion in macular degeneration. These findings indicate that VEPs using sine wave grating and visual contrast sensitivity studies can be used to localize pathology in the visual system of patients exposed to Pfiesteria and that localization of the pathology will depend on the response to orientation of the grating stimulus.…”

Section: Directions For Future Researchconfirming and Extending Priorsupporting

confidence: 57%

Pfiesteria: Review of the Science and Identification of Research Gaps. Report for the National Center for Environmental Health, Centers for Disease Control and Prevention

Samet¹,

Bignami²,

Feldman³

et al. 2001

Environmental Health Perspectives

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The Pfiesteria organism was first identified and named in the early 1990s and its ability to kill fish was documented at the time. Research on the effects of exposure to its toxin on humans is more recent, sparked largely by widely publicized fish kills in the late 1990s and reports of adversely affected persons present at the scenes of the kills. Consequently, the peer-reviewed literature is still limited and substantial research is in progress at institutions in the Atlantic coast states of Maryland, North Carolina, and Virginia, and elsewhere. Dramatic reports of fish kills and illness among persons exposed to water at the time of the kills sparked public concern and reviews by a variety of agencies in the late 1990s. The primary data sources, secondary reviews, and expert panel reports were evaluated by this panel.In approaching its charge, the panel turned to a toxicologically based framework for conducting its review, characterizing the state of the science, and identifying research gaps (Figure 1). Prevention of adverse effects of Pfiesteria will need to be based in an understanding of each element in this framework: the ecological factors that drive concentrations of the organism and its state; the stimuli that lead to toxin production and the nature of the toxin; the mechanism of the toxin's effect on fish; the circumstances and routes of human exposure; and the mechanisms by which human health is adversely affected by the toxin. Sufficient certainty is needed on each of these points to evolve policies that will assure protection of public health and the fish populations. In addition, we need enhanced understanding of the still poorly characterized effects of Pfiesteria on human health.Other reviewers have commented on many elements of this framework; their reviews make clear that there are gaps in scientific understanding, with attendant uncertainty for decision makers, for each of these elements. With substantial research now under way, the panel views the timing of this review as an opportunity to examine the gaps and the extent to which new research findings will set aside uncertainties.Pfiesteria has proved to be a challenging problem. Researchers have referred to the organism as "ephemeral" and "phantom-like."It has multiple forms, transforming itself into a toxin-producing dinoflagellate when it somehow senses the presence of fish. Its toxin apparently destroys the integrity of the skin of fish, allowing the organism to feed; after feeding, the organism transforms into a dormant form. (Throughout this report, we refer to "Pfiesteria toxin," recognizing that the organism may well produce more than one toxin. We use the plural "toxins" in describing the basis for supposing that more than one toxin exists.) There is debate as to whether a pathognomonic lesion occurs in fish. Humans seem to be at risk when their activities lead to contact with toxin-containing water at the time of fish kills. Whether the toxin reaches target tissues by dermal contact or inhalation is unclear. A diffuse syndrome has b...

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Section: Directions For Future Researchconfirming and Extending Priorsupporting

confidence: 57%

Pfiesteria: Review of the Science and Identification of Research Gaps. Report for the National Center for Environmental Health, Centers for Disease Control and Prevention

Samet¹,

Bignami²,

Feldman³

et al. 2001

Environmental Health Perspectives

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“…However, studies of retinal or optic nerve diseases have indicated that the PERG alteration is not necessarily limited to its amplitude but may also be reflected in changes of peak-time, namely, in cases of retinal disorders [11,12]. Meanwhile, there is an increasing number of reports on VECP delays in patients with pure retinal disorders such as X-linked juvenile retinoschisis [17], Stargardt's disease [8], central serous retinopathy [10,[18][19][20] and macular holes [9,21]. All of these authors have concluded that a delayed VECP cannot be considered specific for postretinal neuropathies (eg, demyelinating diseases), and the present data support their view.…”

Section: Discussionmentioning

confidence: 99%

“…Some uncertainty and controversy still remains, however, about the origin of VECP delays in retinal diseases. Lennerstrand [8], Bass and associates [9] and Bodis-Wollner and colleagues [20] have discussed the development of a concomitant optic neuropathy responsible for the VECP delay. Usually the authors excluded this possibility based on ophthalmoscopic inspection of the optic disc [20] or the time course of retinal diseases being too short to allow an anterograde degeneration of neuronal structures [8,20].…”

Section: Discussionmentioning

confidence: 99%

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Retinal origin of VECP delays as revealed by simultaneously recorded ERG to patterned stimuli

Lorenz

Heider

1990

Doc Ophthalmol

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Electroretinal and electrocortical potentials evoked by reversing checkerboards (PERG, PVECP) were simultaneously recorded in diseases of the central retina (10 patients) and in tumor-related optic nerve disorders (11 patients) exhibiting comparable P-100 delays in the PVECP. Retinal diseases showed a peak-time delay both in the PERG and in the PVECP, while optic nerve disorders revealed no delay in the PERG. Thus, simultaneous recording of PERG and PVECP may differentiate retinal from postretinal disorders of the visual system. The method also may provide information about the site of an underlying disorder in cases of visual disturbance without obvious changes of the ocular fundus.

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“…19,51 Retinitis pigmentosa is a disease entity in which the rods and cones progressively degenerate. However, the integrity of the VEP does depend on the integrity of the ganglion cells.…”

Section: Retinal Lesionsmentioning

confidence: 99%

Visual Evoked Potentials in Pediatrics—Abnormal

Goldie¹

2006

Clinical Neurophysiology of Infancy, Childhood, and Adolescence

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The visual evoked potential (VEP) is an objective physiologic measurement of the electrical activation of the visual pathways of the brain that has become a valuable tool in vision research and clinical medicine. Most VEP studies have been performed on the adult and have been used most effectively as a test of optic nerve function. Although the VEP has been most widely used in cases of multiple sclerosis, 1 there are numerous other clinical conditions in which VEPs provide useful information. This chapter concerns the use of the VEP in evaluating the visual system of the infant and young child. Chapter 10 reviews the basic physiology of the developing visual system, particularly as this would relate to the development of the VEP.In this chapter observations about the manner in which the VEPs in children are obtained and interpreted are discussed, and illustrations of their usefulness in different clinical settings are provided. In the first section caveats concerning the techniques and settings used for collecting VEPs in children are given. The latter part of the chapter deals with the utility of the VEP in a variety of disorders affecting the nervous system. First, the usefulness in disorders of development of the visual pathways, in amblyopia ex anopsia, and in compressive lesions of the visual pathways is discussed. Second, the role of VEP in vascularischemic lesions of the visual pathways, metabolic and toxic disorders, demyelinating and dysmyelinating disorders of the developing nervous system, and hypoxicischemic encephalopathy of the premature infant is then reviewed. Finally, clinical issues concerning the use of the VEP in retinal lesions, in occipital infarcts, cortical malformations, and in the setting of dyslexia are discussed.

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Delayed visual evoked potentials are independent of pattern orientation in macular disease

Cited by 18 publications

References 17 publications

Pfiesteria: Review of the Science and Identification of Research Gaps. Report for the National Center for Environmental Health, Centers for Disease Control and Prevention

Pfiesteria: Review of the Science and Identification of Research Gaps. Report for the National Center for Environmental Health, Centers for Disease Control and Prevention

Retinal origin of VECP delays as revealed by simultaneously recorded ERG to patterned stimuli

Visual Evoked Potentials in Pediatrics—Abnormal

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