Lack of visual evoked potentials amplitude decrement during prolonged reversal and motion stimulation in migraineurs

Objective: We evaluated response decrement during a short time repetitive low and high contrast reversal and low contrast motion stimulation in controls and migraineurs. Methods: A total of 39 migraine patients (out of which 19 were in the interictal period and without prophylactic treatment) and 36 healthy volunteers were examined using pattern-reversal (PR-VEP) and motion-onset (M-VEP) visual evoked potentials. Binocular stimulation lasted 2.5 min and the decrement assessment was blinded. Results: Evidence of significant decrement was observed in healthy volunteers for high contrast PR-VEP amplitude of P100-N75 ratios between the fifth and first blocks (0.9; p = 0.001) with a linear decline (-0.7 mu V/min, p = 0.001) and in the P100-N145 amplitude with linear decline (-0.5 mu V/min, p = 0.004). Significant decrement was also observed for the ratio between the fifth and first block P1-N2 amplitudes in M-VEP (0.9, p = 0.006). No significant decrement was noted in the low contrast PR-VEP or among migraineurs. Conclusions: We confirm differences in decrease of VEPs amplitude during short term examination between controls and migraineurs. We showed the decrement deficit also in the extrastriatal regions of the migraineurs' visual cortex. Significance: Low contrast and motion-onset stimuli in short time decrement assessment did not increase the test sensitivity. (C) 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.