Hyperexcitability of occipital cortex in migraine

Abstract

Purpose: The hypothesis that generalized hyperexcitability of the cerebral cortex, more pronounced in the visual area, is a cornerstone in migraine pathophysiology remains unclear. Methods: We stimulated visual cortex using a 90-mm circular coil placed over the occipital scalp in healthy controls and patients with migraine with aura (MA) and without aura (MO) during the interictal period. Twenty-four MA patients, 14 MO patients and 21 healthy controls were studied. Threshold level and prevalence of stimulation-induced phosphene production were compared among MA, MO and HC groups. Results: The difference in proportion of subjects with phosphene generation in MA and control groups (MA 100% versus control 52.4%, p=0.000) and in MO and control (MO 92.8% versus 52.4%, p=0.000) were significant, but there was no significant difference between MA and MO (p=0.056). The difference in threshold levels in MA (MA 48.6%) and controls (98.2%) and in MO (MO 68%) and controls vere significant (p=0.001 andp=0.001 respectively). There vas also a significant difference between MA and MO (p=0.01). Conclusion: Our data strongly suggest that the occipital cortical neurons may be hyperexcitable in migraineurs, at least during the interictal period.

Purpose: The hypothesis that generalized hyperexcitability of the cerebral cortex, more pronounced in the visual area, is a cornerstone in migraine pathophysiology remains unclear. Methods: We stimulated visual cortex using a 90-mm circular coil placed over the occipital scalp in healthy controls and patients with migraine with aura (MA) and without aura (MO) during the interictal period. Twenty-four MA patients, 14 MO patients and 21 healthy controls were studied. Threshold level and prevalence of stimulation-induced phosphene production were compared among MA, MO and HC groups. Results: The difference in proportion of subjects with phosphene generation in MA and control groups (MA 100% versus control 52.4%, p=0.000) and in MO and control (MO 92.8% versus 52.4%, p=0.000) were significant, but there was no significant difference between MA and MO (p=0.056). The difference in threshold levels in MA (MA 48.6%) and controls (98.2%) and in MO (MO 68%) and controls vere significant (p=0.001 andp=0.001 respectively). There vas also a significant difference between MA and MO (p=0.01). Conclusion: Our data strongly suggest that the occipital cortical neurons may be hyperexcitable in migraineurs, at least during the interictal period.