| Objective To observe the changes of visual evoked potential (VEP) in patientswith migraine without aura and in patients with chronic migraine，and to explorethe possible mechanism of both interictal visual cortex excitability changes.Methods20patients with migraine without aura(MO),20patients with chronicmigraine(CM) and20healthy controls (HC) were recruited in this case-control study.The MO group and CM group were recruited from the Department of Neurology, theFirst Affiliated Hospital of Anhui Medical University between November2011andAugust2012. The HC group was recruited from health medical center of First AffiliatedHospital of Anhui Medical University over the same period. The VEP recording of sixsequential blocks of100sweeps was conducted in three groups, i.e.MO, CM, HCgroups. We measured the peak-to-peak amplitude of the N1-P2. We compared block1VEP amplitude among the three groups and the change tendency in amplitude of N1-P2recorded during the six blocks in separate groups.Results VEP amplitude of the first block was significant different among threegroups. VEP amplitude of the first block was significantly lower in the migrainegroup than that in the healthy group[（6.05±2.22）μV <(6.54±1.81) μV，P＜0.05]，but higher in the chronic migraine group than that in the healthy group[（8.32±1.74）μV>(6.54±1.81) μV，P＜0.05]. For the change tendency in amplitudeof N1–P2recorded during the six blocks, the linear trend in the healthy group decreased from blocks1to6(r=-0.03),but increased from blocks1to6in themigraine group (r=0.21)，the linear trend in the chronic migraine group decreasedfrom blocks1to6(r=-0.14).Conclusions Reduced cortical pre-activation is likely to be the cause of thehabituation deficit found in migraine patients between attacks, ultimately due to thehypofunction of the brainstem. The high cortical excitability of chronic migraine maybe attributed to the hypofunction of inhibitory circuits. |
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