title: Value of biofeedback in the treatment of chronic headache: the patients' opinions.
mesh_terms: D001676:Biofeedback, Psychology; D002908:Chronic Disease; D005069:Evaluation Studies as Topic; D006261:Headache / Q000628:therapy*; D006801:Humans; D008881:Migraine Disorders / Q000628:therapy; D009119:Muscle Contraction