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Pattern electroretinography in patients with delayed pattern visual evoked potentials due to distal anterior visual
1Regional Department of Clinical Neurophysiology, Brook General Hospital, London, United Kingdom.
Journal of Neurology, Neurosurgery, and Psychiatry
|December 1, 1989
Summary
Pattern electroretinography (PERG) abnormalities in the P50 component, not N95, indicate distal visual pathway dysfunction. This finding suggests PERG should routinely supplement pattern visual evoked potentials (PVEP) for diagnosing anterior visual pathway issues.
Area of Science:
- Neuroscience
- Ophthalmology
- Clinical Electrophysiology
Background:
- Distal visual pathway dysfunction can be challenging to diagnose using standard neurophysiological methods.
- Optic nerve dysfunction is a common reason for referral for visual pathway assessment.
Purpose of the Study:
- To investigate the utility of pattern electroretinography (PERG) in conjunction with pattern visual evoked potentials (PVEP) for diagnosing distal visual pathway dysfunction.
- To differentiate optic nerve disease from other forms of anterior visual pathway dysfunction.
Main Methods:
- Retrospective analysis of 67 patients with distal visual pathway dysfunction examined between March 1983 and January 1988.
- Performance of both pattern visual evoked potentials (PVEP) and pattern electroretinography (PERG) on all patients.
- Analysis of specific components of the PERG, namely the P50 and N95 waves.
Main Results:
- All 67 patients exhibited delayed PVEP, suggesting visual pathway dysfunction.
- Pattern electroretinography (PERG) consistently showed abnormalities in the main positive P50 component in all patients.
- No patients presented with an abnormality solely confined to the negative N95 component, which is typically associated with optic nerve disease.
Conclusions:
- Abnormalities in the P50 component of PERG are indicative of distal visual pathway dysfunction.
- The PERG's P50 component appears more sensitive to distal visual pathway issues than the N95 component, which is characteristic of optic nerve disease.
- Pattern electroretinography (PERG) should be considered a routine addition to pattern visual evoked potentials (PVEP) for a comprehensive assessment of anterior visual pathway dysfunction.