Cognitive Composite Scores in WRAP
This document describes the calculation of the composite scores in the WRAP database.
The composite scores in WRAP were created by averaging several scores from different neuropsychological tests, after first z-transforming each score to put it on a common scale. Such composite scores, which can be either global or domain-specific in nature, can reduce error variance, making it easier to detect subtle longitudinal change (Jonaitis et al., 2019). Starting in Freeze 18, we will make available six composite scores: three global composites inspired by the work of Mike Donohue and colleagues to define a Preclinical Alzheimer's Cognitive Composite that can be used across studies (Donohue et al., 2014), and three domain-specific composites structured after analyses done on WRAP data by Lindsay Clark (Clark et al., 2016). Data in the paper linked above suggests that these composites are more powerful than both the individual raw test scores and the earlier factor scores.
The following table lists the constituent tests in each composite score and, where available, provides a citation in which the composite is described more fully. I have also attached two text files containing the SQL code used to create these composites, as well as a table of coefficients necessary for their calculation.
Prior to Freeze 18, composite scores were not computed in the WRAP database. In Fall 2018, Erin Jonaitis made available to a small number of researchers a dataset containing composite scores that were calculated using Freeze 17 scores for all but Logical Memory. After data lock for Freeze 17, the WRAP team began a quality control project that resulted in many small (one- or two-point changes) to Logical Memory I and II scores. To maximize compatibility with future freezes, the shared Freeze 17 composites incorporated Logical Memory scores captured from the live database in October 2018. This means that researchers wishing to verify composite calculations on Freeze 17 data using the attached code will notice many small discrepancies in all but the Executive Function composite scores.
Composite name | Column name in database | Constituent neuropsychological scores | See also |
Immediate Learning | cs_imm_lrn | Rey Auditory-Verbal Learning Test, Trials 1-5 Total Score Wechsler Memory Scale-Revised, Logical Memory I Total Score Brief Visuospatial Memory Test-Revised, Immediate Recall | Clark LR, Racine AM, Koscik RL, Okonkwo OC, Engelman CD, Carlsson CM, Asthana S, Bendlin BB, Chappell R, Nicholas CR, Rowley HA, Oh JM, Hermann BP, Sager MA, Christian BT, Johnson SC. Beta-amyloid and cognitive decline in late middle age: Findings from the Wisconsin Registry for Alzheimer's Prevention study. Alzheimers Dement. 2016 Jul;12(7):805-14. doi: 10.1016/j.jalz.2015.12.009. Epub 2016 Jan 21. PubMed PMID: 26806386; PubMed Central PMCID: PMC4947439. |
Delayed Recall | cs_del_rec | Rey Auditory-Verbal Learning Test, Delayed Recall Wechsler Memory Scale-Revised, Logical Memory II Total Score Brief Visuospatial Memory Test-Revised, Delayed Recall | Clark LR, Racine AM, Koscik RL, Okonkwo OC, Engelman CD, Carlsson CM, Asthana S, Bendlin BB, Chappell R, Nicholas CR, Rowley HA, Oh JM, Hermann BP, Sager MA, Christian BT, Johnson SC. Beta-amyloid and cognitive decline in late middle age: Findings from the Wisconsin Registry for Alzheimer's Prevention study. Alzheimers Dement. 2016 Jul;12(7):805-14. doi: 10.1016/j.jalz.2015.12.009. Epub 2016 Jan 21. PubMed PMID: 26806386; PubMed Central PMCID: PMC4947439. |
Executive Function | cs_exec_fn | Trail-Making Test, Part B Stroop Test, Color-Word (Corrected) Wechsler Adult Intelligence Scale-R, Digit Symbol Total Score | Clark LR, Racine AM, Koscik RL, Okonkwo OC, Engelman CD, Carlsson CM, Asthana S, Bendlin BB, Chappell R, Nicholas CR, Rowley HA, Oh JM, Hermann BP, Sager MA, Christian BT, Johnson SC. Beta-amyloid and cognitive decline in late middle age: Findings from the Wisconsin Registry for Alzheimer's Prevention study. Alzheimers Dement. 2016 Jul;12(7):805-14. doi: 10.1016/j.jalz.2015.12.009. Epub 2016 Jan 21. PubMed PMID: 26806386; PubMed Central PMCID: PMC4947439. |
Preclinical Alzheimer's Cognitive Composite (three-test version) | pacc3 | Rey Auditory-Verbal Learning Test, Trials 1-5 Total Score Wechsler Memory Scale-Revised, Logical Memory II Total Score Wechsler Adult Intelligence Scale-R, Digit Symbol Total Score | 1: Mormino EC, Papp KV, Rentz DM, Donohue MC, Amariglio R, Quiroz YT, Chhatwal J, Marshall GA, Donovan N, Jackson J, Gatchel JR, Hanseeuw BJ, Schultz AP, Aisen PS, Johnson KA, Sperling RA. Early and late change on the preclinical Alzheimer's cognitive composite in clinically normal older individuals with elevated amyloid β. Alzheimers Dement. 2017 Sep;13(9):1004-1012. doi: 10.1016/j.jalz.2017.01.018. Epub 2017 Feb 28. PubMed PMID: 28253478; PubMed Central PMCID: PMC5573651. |
Preclinical Alzheimer's Cognitive Composite (four-test version with MMSE) | pacc4 | Rey Auditory-Verbal Learning Test, Trials 1-5 Total Score Wechsler Memory Scale-Revised, Logical Memory II Total Score Wechsler Adult Intelligence Scale-R, Digit Symbol Total Score Mini-Mental State Exam, Total Score | Donohue MC, Sperling RA, Salmon DP, Rentz DM, Raman R, Thomas RG, Weiner M, Aisen PS; Australian Imaging, Biomarkers, and Lifestyle Flagship Study of Ageing; Alzheimer’s Disease Neuroimaging Initiative; Alzheimer’s Disease Cooperative Study. The preclinical Alzheimer cognitive composite: measuring amyloid-related decline. JAMA Neurol. 2014 Aug;71(8):961-70. doi: 10.1001/jamaneurol.2014.803. PubMed PMID: 24886908; PubMed Central PMCID: PMC4439182. |
Preclinical Alzheimer's Cognitive Composite (four-test version with CFL) | pacc4_cfl | Rey Auditory-Verbal Learning Test, Trials 1-5 Total Score Wechsler Memory Scale-Revised, Logical Memory II Total Score Wechsler Adult Intelligence Scale-R, Digit Symbol Total Score Controlled Oral Word Association Test, Letter Fluency ('C,F,L') | Will be available in Freeze 19. |