Exaggerated response to pattern reversal visual evoked potential among migraineurs

Area of Science:

• Neuroscience
• Ophthalmology
• Clinical Electrophysiology

Background:

• Visual evoked potential (VEP) studies in migraineurs have yielded inconsistent results.
• Understanding the impact of visual stimuli parameters on VEP is crucial for migraine diagnostics.

Purpose of the Study:

• To investigate the association between checkerboard check-size and reversal rates on pattern reversal VEP latency and amplitude in migraineurs.
• To compare VEP responses between migraineurs and healthy controls under varying visual stimulation conditions.

Main Methods:

• Monocular VEP responses were recorded from 133 migraineurs and 111 controls.
• Stimuli included checkerboard patterns with reversal frequencies of 0.5-4 Hz and check sizes from 16x16 to 128x128 (spatial frequencies 0.475-4.112 cpd).
• 100 responses were averaged for each condition, with a 3-minute rest between reversal frequency changes.

Main Results:

• A linear increase in VEP latency was observed with decreasing check-size in both groups.
• Migraineurs showed significantly higher latencies compared to controls at equivalent reversal rates.
• Amplitude A2 exhibited an inverted 'U' trend, peaking at 32x32 check size (1.029 cpd), with an exaggerated response in migraineurs.

Conclusions:

• Differential activation of retinocortical pathways and cortical areas may explain variable VEP responses.
• The enhanced amplitude at a modest check-size suggests a role for foveal-parafoveal fibers in migraine.
• Exaggerated physiological responses to visual stimuli likely contribute to prolonged latencies and higher amplitudes in migraineurs.