Huskisson EC Measurement of pain. Lancet. 1974 Nov 9;2(7889):1127-31. doi: 10.1016/s0140-6736(74)90884-8. No abstract available.
Kersten P, White PJ, Tennant A Is the pain visual analogue scale linear and responsive to change? An exploration using Rasch analysis. PLoS One. 2014 Jun 12;9(6):e99485. doi: 10.1371/journal.pone.0099485. eCollection 2014.
Moskaliuk J, Kimmerle J, Cress U Virtual reality 2.0 and its application in knowledge building. In handbook of research on web 2.0, 3.0, and X. O: technologies, business and social applications. USA: IGI Global, 2010.
Robleda G, Sillero-Sillero A, Puig T, Gich I, Banos JE Influence of preoperative emotional state on postoperative pain following orthopedic and trauma surgery. Rev Lat Am Enfermagem. 2014 Oct;22(5):785-91. doi: 10.1590/0104-1169.0118.2481.
Shek DT The Chinese version of the State-Trait Anxiety Inventory: its relationship to different measures of psychological well-being. J Clin Psychol. 1993 May;49(3):349-58. doi: 10.1002/1097-4679(199305)49:33.0.co;2-j.
Shek DTL The factorial structure of the Chinese version of the state-trait anxiety inventory: a confirmatory factor analysis. Psychol Edu Meas. 1991;51(4):985-997. doi:10.1177/001316449105100418
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.