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Visual evoked potential in patients with cerebral asthenopia.
Acta Neurologica Scandinavica
|June 1, 1979
Summary
Cerebral asthenopia, linked to brain lesions, shows reduced visual evoked potential (VEP) amplitudes. This objective finding suggests visual cortex involvement but VEP is not a reliable diagnostic tool due to overlap.
Area of Science:
- Neuroscience
- Ophthalmology
- Clinical Electrophysiology
Background:
- Cerebral asthenopia, a symptom associated with diffuse brain lesions, is frequently underestimated.
- Objective correlates for cerebral asthenopia have not been previously established.
- This study investigates the potential of visual evoked potentials (VEP) as an objective measure.
Purpose of the Study:
- To identify an objective correlate for cerebral asthenopia.
- To compare VEP characteristics between patients with asthenopia and healthy controls.
- To explore the diagnostic utility of VEP in cerebral asthenopia.
Main Methods:
- Averaged visual evoked potentials (VEP) were recorded from 10 patients with asthenopia and 20 normal subjects.
- Bipolar recording was used, stimulating both eyes and each eye individually over the occipital lobes.
- Somatosensory evoked potentials (SEP) were also assessed for comparison.
Main Results:
- No significant differences in VEP latency were observed between groups.
- Patients with asthenopia exhibited significantly reduced VEP amplitude compared to controls.
- Differences in VEP habituation and lateralization were noted; SEP amplitudes showed no difference.
Conclusions:
- Reduced VEP amplitude serves as an objective correlate for asthenopia, likely indicating visual cortex involvement.
- The observed VEP amplitude differences appear to be modality-specific.
- VEP is deemed unsuitable for diagnosing cerebral asthenopia due to substantial overlap between patient and control amplitudes.