In the summary entitled “Is Botulinum Toxin Type A Effective for Headache Prophylaxis?” the second-to-last sentence of the second paragraph should have included the word less, rather than more: “There is no clear effect for either episodic migraine, defined as occurring on less than 15 days a month, or CTTH.”
We apologize for the error and thank Dariush Saghafi for pointing it out to us. The corrected version now appears on our website.