Cortical Abnormalities and the Visual Evoked Response

Blumhardt, L D; Halliday, A. M.

doi:10.1007/978-94-009-8656-5_36

Cited by 14 publications

(5 citation statements)

References 22 publications

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“…The four patients with completely normal VEPs all had full visual fields. This is largely in agreement with the opinion of Blumhardt and Halliday (1981) that the VEP 'appears to provide no information on the extent and localization of lesions outside the visual pathways'. It should be noted, however, that six patients (three with only quadrantic field defects) had equivocally abnormal VEPs.…”

Section: Discussionsupporting

confidence: 80%

“…Subsequent reports on patients with more posteriorly situated lesions producing homonymous visual field defects (e.g. Holder, 1980, Blumhardt andHalliday, 1981;Kuroiwa and Celesia, 1981;Streletz et al, 1981;Blumhardt et al, 1982;Chain et al, 1982) also demonstrated the frequent occurrence of abnormal VEPs. There are, however, many problems in this area of clinical neurophysiology, for example the possible effects of differing pathologies on the type of abnormality observed and the percentage of abnormal VEPs in patients with clinically and neuroradiologically demonstrable lesions, which when resolved will assist in determining the value of VEP examination in the objective assessment of such lesions and in the accurate interpretation of abnormal VEPs recorded in patients yet to undergo further investigation.…”

mentioning

confidence: 99%

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Pattern visual evoked potential in patients with posteriorly situated space-occupying lesions

Holder¹

1985

Doc Ophthalmol

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The potentials evoked by pattern reversal stimulation (2/sec, 11 degrees field, 26' high contrast checks) are described in 22 patients with intracranial space-occupying lesions lying posterior to the optic chiasm. Seventeen (77%) of these patients had clinically demonstrable visual field defects. The nature and position of the lesion was defined by CT scan, by cerebral angiography, or at operation. Completely normal pattern visual evoked potentials (VEPs) were recorded in four patients (18%), all of whom had full visual fields. Definitely abnormal VEPs occurred in 12 patients (55%), 11 with visual field defects. The remaining six patients (27%), all with visual field defects, had VEPs that were inconsistently abnormal and they are rated as equivocal. The findings are discussed with particular attention to the importance of stimulus and recording parameters.

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Section: Discussionsupporting

confidence: 80%

mentioning

confidence: 99%

Pattern visual evoked potential in patients with posteriorly situated space-occupying lesions

Holder¹

1985

Doc Ophthalmol

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“…Therefore, electrodes over the scalp contralateral to the activated cortex pick up activity associated with half-field stimulation (Halliday 1982). It has been reported that some healthy adult subjects can show marked occipital asymmetries following full-field pattern stimulation (Blumhardt and Halliday 1981). However, none of our age-matched controls showed the degree of asymmetry following full-field stimulation demonstrated by our two patients.…”

Section: Discussioncontrasting

confidence: 65%

Detection of Isolated Occipital Lobe Anomalies During Early Childhood

Lambert

Kriss

Taylor

1990

Develop Med Child Neuro

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SUMMARY The authors report two children with isolated occipital lobe anomalies detected by visual evoked potentials (VEPs) and confirmed by MRI and CT scanning. Both had a markedly asymmetrical occipital distribution of flash and pattern VEPs. One child had acuity reduced to 6/36, and testing on confrontation suggested an homonymous hemianopia. The second child was visually inattentive to one side during infancy. Neither child had band atrophy of the optic disc or an afferent pupillary defect. Isolated abnormalities of the occipital lobes are difficult to detect by clinical examination during infancy and early childhood. Recording VEPs from a horizontal array of occipital electrodes can be helpful in detecting subtle occipital lobe abnormalities. RÉSUMÉ Détection des anomalies isolées du lobe occipital durant la premère enfance Les auteurs décrivent deux enfants avec anomalies isolées du lobe occipital détectées par les potentiels évoqués visuels et confirmées par IRM et tomodensitométrie. Dans les deux cas, il y avait une assymétrie marquée dans la distribution occipitale des potentiels évoqués visuels au flash et aux images. L'un des enfants avait une acuité réduite à 6/36 èmes et les épreuves de comparaison suggéraient uine hémianopsie latérale homonyme. Le second enfant avait une innatention visuelle d'un côté durant la première enfance. Aucun des enfants ne présentait d'atrophie en bande de la papille ou de défaut pupillaire afférent. Les anomalies isolées des lobes occipitaux sont difficiles à déceler par examen clinique durant les premières années. L'enregistrement des potentiels évoqués visuels par un réseau horizontal d'électrodes occipitales peut être utile pour détecter des anomalies limitées du lobe occipital. ZUSAMMENFASSUNG Isolierte Occipitallappenanomalien im frühen Kindesalter Die Autoren berichten über zwei Kinder mit isolierten Occipitallappenanomalien, die durch visuell evozierte Potentiale festgestellt und durch MRI und CT Untersuchungen bestätigt wurden. Die visuell evozierten Potentiale beider Patienten hatten eine auffallend asymmetrische occipitale Anordnung. Ein Kind hatte eine Sehschärfenverminderung auf 6/36 und die Untersuchung der Gesichtsfelder ließ an eine homonyme Hemianopsie denken. Das zweite Kind hatte einen einseitigen Gesichtsfeldausfall im Kindesalter. Keins der Kinder hatte eine bandförmige Papillenatrophie oder eine Störung der affarenten Pupillenmotorik. Isolierte Occipitallappenanomalien sind durch klinische Untersuchungen im Kindes‐ und Jugendalter schwer zu erfassen. Die Ableitung der visuell evozierten Potentiale über horizontal, bogenförmig angeordnete Elekroden im Occipitalbereich kann eine Hilfe sein, eine Occipitallappenanomalie zu erkennen.

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“…This has been indicated by neuropathological studies (Brun and Gustafson, 1976), positron emission scanning (Benson, 1982), and visual psychophysics (Schlotterer et al, 1983). The P100 component of the pattern reversal VEP is known to reflect pathology up to and including the primary visual cortex but is insensitive to widespread lesions that leave the primary projection area intact (Blumhardt and Halliday, 1981). The component s of the flash VEP occurring before 100 ms (including P1) are also believed to originate from the primary visual cortex (Ciganek, 1961;Vaughan, 1966).…”

Section: Discussionmentioning

confidence: 99%

The flash and pattern VEP as a diagnostic indicator of dementia

1986

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Ninety-one patients with forgetfulness, confusion and depression were referred for visual evoked potential and electroencephalographic investigation. The patients were subdivided, on clinical symptoms alone, into a group of 41 with evidence of dementia and a patient control group of 50 with effective disorders. A second control group of 30 normal volunteers of equivalent age was used. In dementia the P2 component of the flash visual evoked potential is delayed, while the pattern reversal P100 component is of normal latency. This unusual combination of results from the two different visual stimuli is shown to be more specific than either the electroencephalogram or computerised tomography in the diagnosis of dementia.

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Cortical Abnormalities and the Visual Evoked Response

Cited by 14 publications

References 22 publications

Pattern visual evoked potential in patients with posteriorly situated space-occupying lesions

Pattern visual evoked potential in patients with posteriorly situated space-occupying lesions

Detection of Isolated Occipital Lobe Anomalies During Early Childhood

The flash and pattern VEP as a diagnostic indicator of dementia

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