Impaired visual inhibition in migraine with aura.

OBJECTIVE

The pathophysiology of migraine with or without aura (MA, MO) is still a matter of debate. We thus studied patients with MA and MO by means of paired-pulse flash-visual evoked potentials (paired F-VEPs). This technique, recently revived, analyses the overall excitability of visual system as detected from the cortical occipital signal.

METHODS

We enrolled 13 adult patients with MO and 13 with MA. Twenty-two normal subjects of similar age and sex acted as controls. Stimuli were single flashes, intermingled at random to flash pairs at critical interstimulus intervals (ISIs, 16.5-125ms) with closed and open eyes. The "single"(unconditioned) F-VEP was split into a "main complex" (50-200ms after the flash) and a "late response" (200-400ms). As for paired stimulation, the "test" F-VEP emerged from electronic subtraction of the "single" F-VEP to the "paired" F-VEP. Its size was expressed as "test"/"single"F-VEP∗100.

RESULTS

As for paired F-VEPs, the "main complex" of the "test" F-VEP in the MA group did not show the size reduction (at ISIs 50-62.5ms) which was typical among the control and MO groups (p⩽0.016) in the "eyes-closed" state.

CONCLUSIONS

Paired F-VEPs document a defective neural inhibition in the visual system of patients with MA.

SIGNIFICANCE

Paired F-VEPs may warrant inclusion in future preclinical/clinical studies, to evaluate its potential role in the pathophysiology and management of MA.