Outcome measurement in behavioral headache research: headache parameters and psychosocial outcomes.

The experience of pain is complex and includes multiple dimensions or aspects, such as sensory and affective (among others). Headache includes not only pain, but also associated symptoms that can further diversify the relevant dimensions. Subjective ratings of head pain, sampled daily, have come to be regarded as the "gold standard" in behavioral headache research. Primary measures of headache include the attack frequency or headache days per month. Secondary measures of headache may include headache activity/index, headache duration, peak headache severity, and/or frequency of severe headaches per month. Secondary measures of disability and quality of life include Migraine Disability Assessment (MIDAS), Headache Impact Test (HIT), Headache Disability Inventory (HDI). Secondary nonheadache measures include medication consumption, psychiatric symptoms, stress and coping, treatment satisfaction and preference, side effects, and others. Researchers should include not only primary measures of headache, but also secondary measures, disability and quality of life, and nonheadache measures. All measures should be clearly defined and reported. A baseline period that is adequate for each measure needs inclusion and a minimum of 4 weeks is recommended for primary headache measures. Specific suggestions for future research directions are provided.