ABSTRACT
Headache disorders are an exceedingly common patient complaint and have been described throughout recorded medical history. Symptoms of head pain were noted as early as 7000 B.C. (Lyons & Petrucelli, 1978), and Neolithic trepanned skulls suggest the extreme measures once taken to relieve head pain that was attributed to evil spirits (Venzmer, 1972). Currently, the National Headache Foundation reports that more than 45 million Americans have chronic, recurring headaches. Each year, U.S. businesses lose billions of dollars to absenteeism and medical expenses caused by headache, and headache sufferers spend in excess of $4 billion on nonprescription analgesics (National Headache Foundation, 2000). Headache is responsible for approximately 10 million physician consultations per year (Linet & Stewart, 1987), and it is the fourth most common reason for emergency room visits in the United States (McCaig & Burt, 2003).
