Exploring MCI subtypes in the NACC database

 
   Lead Investigator:    Emily Edmonds
   Institution      :    University of California San Diego
   E-Mail           :    ecedmonds@ucsd.edu
   Proposal ID      :    481



   Proposal Description:
   Our proposed analysis involves identifying distinct subtypes of mild cognitive impairment (MCI) using data from the National Alzheimer???s Coordinating Center(NACC) database. The classification of MCI has traditionally involved a distinction between amnestic and non-amnestic MCI (Petersen, 2004 Winblad et al., 2004). However, recent research has shown that MCI can be further differentiated into subtypes (Bondi et al., 2014 Clark et al., 2013 Edmonds et al., 2014 Libon et al., 2010). Using cluster analysis of neuropsychological test performance, our group recently found several empirically-derived subtypes of MCI in the (ADNI) database, including an Amnensic, a Dysexecutive, and a Dysnomic subtype, each characterized by different performance on neuropsychological measures (Edmonds et al., 2014). These more nuanced MCI subtypes may have advantages over the conventional classification system,as the dichotomous amnestic/non-amnestic may obscure the heterogeneity of MCI by combining all patients with non-memory impairments into one group.                                                                                                  We hope to validate these empirically-derived MCI subtypes by performing a        statistical cluster analysis of cognitive test performance of NACC participants classified as having MCI. Despite differences in the specific cognitive tests that were used to measure cognitive abilities, we hypothesize that we will find a cluster structure similar to our previous studies. Such a finding would provide evidence for the stability and generalizability of the MCI subtypes.