Frequency-dependent habituation deficit of the nociceptive blink reflex in aura with migraine headache. Can migraine aura play a modulating role?

Objective To study the influence of the migraine aura on the trigeminal nociception, we investigated the habituation of the nociceptive blink reflex (nBR) R2 responses in aura with migraine headache (AwMH) and comparatively in migraine without aura (MWoA) and healthy (HS) subjects. Methods Seventeen AwMH, 29 MWoA and 30 HS were studied. We delivered a series of 26 electrical stimuli, at different stimulation frequencies (SF) (0.05, 0.1, 0.2, 0.3, 0.5, 1Hz), subsequently subdivided in five blocks of five responses for each SF. Habituation was measured as the percentage decrease of the R2 area across the blocks. Results A significant frequency-dependent habituation deficit of the nBR R2 responses was found from 1 to 0.2 Hz SF in both MWoA and AwMH when compared to HS. AwMH did not shown habituation deficit at the higher 1 Hz SF and showed a less consistent deficit at 0.5 and 0.3 Hz SF. Conclusions We demonstrated in AwMH a deficit of habituation, although less pronounced than that observed in MWoA of comparable clinical severity. Significance We hypothesize that AwMH and MWoA share some pathogenetic aspects and that migraine aura physiopathology may play a modulating role on the excitability of the nociceptive trigeminal pathways.