Motor and occipital cortex excitability in migraine patients

Objective: We evaluated motor and occipital cortex excitability ill migraine patients using transcranial magnetic Stimulation. Methods: In this study, we included 15 migraine patients with aura (MwA), 15 patients without aura (MwoA) between attacks, and 31 normal healthy controls. Motor thresholds at rest, amplitudes of motor evoked potentials, central motor conduction time and cortical silent period were measured by stimulation of the motor cortex by using 13.5 cm circular coil and recording from abductor digiti minimi muscle. Additionally, phosphene production and the threshold of phosphene production was determined by stimulation of the visual cortex with the same coil. Results: No significant differences were observed between the groups with respect to the motor thresholds, Motor evoked potential max/compound muscle action potential max (MEPmax/Mmax) amplitudes, central motor conduction times and duration of cortical silent period. Although not statistically significant, the proportion of the migraineurs with phosphene generation (90%) was found to be higher than that of normal controls (71%). Phosphene threshold levels in migraine patients, however, were significantly lower than those of the controls with MwA patients having the lowest levels. Conclusion: Out-findings indicate that the occipital cortex, but not the motor cortex, is hyperexcitable in migraine patients.