ABSTRACT
BACKGROUND: Cortical hyperexcitability is proposed to be the putative basis for the physiological disturbances in migraine. Recent studies have demonstrated that divalproex sodium effectively prevents migraine. The cortical silent period (CSP) elicited by transcranial magnetic stimulation (TMS) reflects the cortical inhibition of the central motor pathway. METHODS: We studied the CSP of both first dorsal interossei muscles evoked by TMS in 15 migraine patients and 15 normal subjects. As a prophylactic therapy, 15 migraine patients were treated with divalproex sodium 500~750 mg/day. After 3 months, we studied the CSP in migraine patients for the purpose of comparing with results before medication. RESULTS: The CSP was shorter in migraine patients than in controls (135.8+/-27.8 msec vs 203.7+/-32.2 msec, p<0.001). After treatment with divalproex sodium, the CSP was significantly prolonged in migraine patients (196.9+/-31.0msec, p=0.001). CONCLUSIONS: The shortened CSP in migraine patients suggests increased excitability of the cortical neuron in migraine. The prolonged CSP after medication in migraine patients suggests that the divalproex sodium may play a role in the prophylaxis of migraine by decreasing cortical neuronal hyperexcitability. (J Korean Neurol Assoc 19(5):489~493, 2001)