title: Specific and nonspecific effects in the biofeedback treatment of tension headache: 3-year follow-up.
mesh_terms: D000328:Adult; D001676:Biofeedback, Psychology; D004576:Electromyography; D005500:Follow-Up Studies; D006261:Headache / Q000628:therapy*; D006801:Humans; D009129:Muscle Tonus