Memory loss is a common complaint in headache sufferers. In a 2004 study, which was published in The Journal of Headache and Pain, 71 patients, 50 women and 21 men, affected by chronic daily headache with different diagnoses at onset and at study entry, underwent a test battery in order to evaluate both short- and long-term memory. A percentage of patients, ranging from 2% to 56%, according to the different tests, showed a worse performance than normal subjects. The percentage of the subjects with memory difficulty was higher in women and in patients with migraine-type headache at onset. Researchers concluded that a complex neurotransmitter disorder might account for impairment of both short-term and long-term memory in headache patients.

(Mariantonietta Savarese. Memory functions in patients with chronic daily headache: The Journal of Headache and Pain; Volume1, Supplement 1/September, 2004).