Contingent negative variation in migraine: effect of beta blocker therapy

The contingent negative variation (CNV) has been useful in differentiating common migraine from muscle tension headaches as well as classic migraine. This study evaluated CNV in a group of patients with muscle tension headache, common migraine, and classic migraine. Furthermore, we evaluated the effect of beta blocker therapy on the CNV. The patients with common migraine responded to beta blocker therapy. CNV amplitude decreased during beta blocker treatment and with resolution of headache episodes. Further studies are indicated as CNV may be useful to evaluate the effect of drug treatment in common migraine.