Is Palinopsia in Migraineurs a Phenomenon of Impaired Habituation of Visual Cortical Neurons?

Palinopsia in migraine has been reported recently, which may be due to the dysexcitability of visual cortical neurons. In this cross-sectional study, we report the correlation of neuronal dysexcitability with palinopsia using pattern shift visual evoked potential (PSVEP) in 91 migraineurs and 25 healthy controls. The presence of palinopsia was evaluated using a novel objective method, and revealed more frequent palinopsia in the migraineurs compared to the controls (53 of 91 [58.2%] vs 3 of 25 [12%]; P  < .001). Five consecutive blocks of PSVEP were recorded for the evaluation of sensitization and impaired habituation. Amplitudes of N75 and P100 in block 1 were considered for sensitization. Impaired habituation of N75 and P100 was considered if any amplitudes in blocks 2 to 5 were higher than block 1. Impaired habituation was more frequent in migraineurs compared with the controls, and was more marked in wave N75 (81.3% vs 32%; P  < .001) than wave P100 (63.7% vs 44%; P  = .12). Impaired habituations of wave N75 (81.7% vs 58.9%; P  = .008) and wave P100 (71.7% vs 46.4%; P  = .008) were more frequent in those with palinopsia compared with those without. There was a lack of suppression of P100 amplitude in block 3 in the palinopsia group compared to the controls. The duration of palinopsia correlated with the extent of impaired habituation of N75. It can be concluded that the impaired habituation of PSVEP waveforms is a biomarker of palinopsia in migraine.