Shirley Ryan AbitilyLab 1 article published in JoVE Behavior Lexical Decision Task for Studying Written Word Recognition in Adults with and without Dementia or Mild Cognitive Impairment Alexandre Nikolaev1, Eve Higby2,3, JungMoon Hyun4, Sameer Ashaie5,6 1Helsinki Collegium for Advanced Studies, University of Helsinki, 2University of California, Riverside, 3California State University, East Bay, 4Hunter College, City University of New York, 5Feinberg School of Medicine, Northwestern University, 6Shirley Ryan AbilityLab This article describes how to implement a simple lexical decision experiment to assess written word recognition in neurologically healthy participants and in individuals with dementia and cognitive decline. We also provide a detailed description of reaction time analysis using principal components analysis (PCA) and mixed-effects modeling.