Robust Norms

 
   Lead Investigator:    Brandon Gavett
   Institution      :    University of Colorado at Colorado Springs
   E-Mail           :    bgavett@uccs.edu
   Proposal ID      :    128


   Publications:


1  Gavett BE, Ashendorf L, Gurnania AS
   Reliable Change on Neuropsychological Tests in the Uniform Data Set
   Journal Article  J Int Neuropsychol Soc,21:558-567,2015,PMC4860819

   PUBLISHED





   Proposal Description:
   Most neuropsychological test instruments are interpreted using normative  data - data that are collected from a putatively healthy sample in order  to understand the expected mean and variance in test scores produced by  nondiseased persons. These normative data are typically used to  interpret an individual person's test score in the context of his or her  peers, with corrections for demographic factors such as age, education,  sex, and race. When applying norms for the purpose of understanding  change in older adults, there are two critical issues that could  undermine interpretation. First, it is difficult to determine whether  the normative data are "robust" to latent causes of cognitive  difficulties. A person who is part of a normative sample may be in the  very early stages of Alzheimer's disease, but may not be manifesting  clinically obvious cognitive difficulties at the time of the normative  sampling. Recent efforts have been made to include participants known to  be disease-free after several years of follow-up ("robust norms").  Second, norms are generally cross-sectional in nature, not longitudinal,  yet are interpreted to reflect magnitude of change when used for  repeated assessments of patients or research participants. We propose to  address these two weaknesses in the current study. We will identify  individuals from the NACC UDS data set who have been confirmed through  longitudinal clinical assessment to be cognitively healthy. We will  examine data from at least three annual assessments completed by  participants who were diagnosed as being cognitively normal at the most  recent evaluation. We will then retrospectively examine the previous  visits in order to quantify the degree of change observed across time in  this putatively healthy sample. Our primary focus will be on identifying  the rate of change in cognitive abilities over time (through the  calculation of reliable change indices and other regression-based change  methods). We seek to