[Problems in and approaches to the design and evaluation of therapeutic studies in patients with headache.].

A review of studies on migraine therapy shows a large heterogeneity in the clinical evaluation of different drugs and behavioral approaches. The percentages of efficacy of beta-blockers or behavior therapy (relaxation, biofeedback) range from 30% to 80%. Methodological differences from one author to another in the design and conduct of the studies might be causes of this variation. For both clinical practice and empirical research (e.g. replication of treatment studies) an uniformity in the application of different methodological techniques should be sought. This paper discusses the influence of methodological aspects on the success rates of treatment for chronic headaches, especially migraine. We question the present practice of applying traditional group experiments in headache research. Double-blind and placebo-controlled studies are often required, but this demand often cannot be niet in empirical reality because of the individuality of the patient or the heterogeneity of the symptoms. We discuss some alternative approaches that could be used in empirical research on headache therapy. The application of single-case experiments as well as methods of time-series analysis are described as a more appropriate approach to the evaluation of studies on chronic headaches.