title: Pain measurement and Beecher's challenge: 50 years later.
authors: Charles
authors: C
authors: Berde
authors: Patrick
authors: P
authors: McGrath
mesh_terms: D002648:Child; D003952:Diagnostic Imaging; D004594:Electrophysiology; D005712:Galvanic Skin Response / Q000502:physiology; D049673:History, 20th Century; D006801:Humans; D010146:Pain / Q000188:drug therapy; D059408:Pain Management; D010147:Pain Measurement / Q000266:history* / Q000592:standards / Q000639:trends; D010166:Palliative Care