Charter RA Sample size requirements for precise estimates of reliability, generalizability, and validity coefficients. J Clin Exp Neuropsychol. 1999 Aug;21(4):559-66. doi: 10.1076/jcen.21.4.559.889.
Costa SL, Genova HM, DeLuca J, Chiaravalloti ND Information processing speed in multiple sclerosis: Past, present, and future. Mult Scler. 2017 May;23(6):772-789. doi: 10.1177/1352458516645869. Epub 2016 May 9.
Galinowski A, Lehert P Structural validity of MADRS during antidepressant treatment. Int Clin Psychopharmacol. 1995 Sep;10(3):157-61. doi: 10.1097/00004850-199510030-00004.
MacCallum RC, Widaman KF, Preacher KJ, Hong S Sample Size in Factor Analysis: The Role of Model Error. Multivariate Behav Res. 2001 Oct 1;36(4):611-37. doi: 10.1207/S15327906MBR3604_06.
Monaco M, Costa A, Caltagirone C, Carlesimo GA Forward and backward span for verbal and visuo-spatial data: standardization and normative data from an Italian adult population. Neurol Sci. 2013 May;34(5):749-54. doi: 10.1007/s10072-012-1130-x. Epub 2012 Jun 12. Erratum In: Neurol Sci. 2015 Feb;36(2):345-7.
Sakpal TV Sample size estimation in clinical trial. Perspect Clin Res. 2010 Apr;1(2):67-9.
Zimmerman M, Chelminski I, Posternak M A review of studies of the Hamilton depression rating scale in healthy controls: implications for the definition of remission in treatment studies of depression. J Nerv Ment Dis. 2004 Sep;192(9):595-601. doi: 10.1097/01.nmd.0000138226.22761.39.
Validation and Standardization of the Consecutive-Letter Substitution Task (CST) Test in an Italian Population Sample
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.
