Cognitive Composite Scores in WRAP

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 May_2021, will make available six composite scores: three domain-specific composites structured after analyses done on WRAP data by Lindsay Clark (Clark et al., 2016); and seven 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). Each composite is available with two scalings: one that has been z-transformed such that scores from cognitively unimpaired participants at their first observation have a mean of 0 and a standard deviation of 1 (these begin with z_); and one that has been transformed so that the same set of scores follows a distribution with a mean of 100 and a standard deviation of 15 (these begin with std_). Data in the paper linked above suggests that composites are more powerful than both individual raw test scores and our earlier factor scores that were based on similar inputs.

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.

Scores from Freeze 18 through Freeze May_2020 were computed without the final rescaling step. These remain available with the suffix _old to indicate that they are now deprecated (e.g., pacc3_old), but remain in the dataset for consistency. Prior to Freeze 18, composite scores were not computed in the WRAP database. Earlier freezes had included factor scores that had been developed on the basis of factor analyses of the first and second waves (Dowling et al., 2010; Koscik et al., 2014). Because these factor scores demonstrated more unwanted longitudinal variability compared to the cognitive composites (Jonaitis et al., 2019), they are no longer included in freezes.

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	z_imm_lrn, std_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	z_del_rec, std_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	z_exec_fn, std_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 with Digit Symbol)	z_pacc3_ds, std_pacc3_ds	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 (three-test version with Trails B)	z_pacc3_tmtb, std_pacc3_tmtb	Rey Auditory-Verbal Learning Test, Trials 1-5 Total Score  Wechsler Memory Scale-Revised, Logical Memory II Total Score  Wechsler Adult Intelligence Scale-R Trail-Making Test B (reversed)	Created for greater similarity to crosswalked PACC3 in UP data (WRAP + ADRC).
Preclinical Alzheimer's Cognitive Composite (four-test version with Digit Symbol and MMSE)	z_pacc4_ds_mmse, std_pacc4_ds_mmse	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 Trails B and MMSE)	z_pacc4_tmtb_mmse, std_pacc4_tmtb_mmse	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 Trail Making Test B (reversed)	Created for greater similarity to crosswalked PACC4 in UP data (WRAP + ADRC).
Preclinical Alzheimer's Cognitive Composite (four-test version with CFL)	z_pacc4_ds_cfl, std_pacc4_ds_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')
Preclinical Alzheimer's Cognitive Composite (five-test version with Animal Naming, Digit Symbol, and MMSE)	z_pacc5_animtot, std_pacc5_animtot	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, Animal Naming Total Score
Preclinical Alzheimer's Cognitive Composite (five-test version with CFL, Digit Symbol, and Trails B)	z_pacc5_cfl, std_pacc5_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'), Trail Making Test B (reversed)