The Preclinical Alzheimer's Cognitive Composite (PACC) is a baseline standardized composite of

pacc(dd, keepComponents = FALSE)



data frame to score with variables ADASQ4, LDELTOTAL, DIGITSCOR, MMSE, TRABSCOR,, and VISCODE


should components and z scores be returned? Defaults to FALSE so that just the composite scores are returned.


The data.frame with appended columns for mPACCdigit and mPACCtrailsB


  • Free and Cued Selective Reminding Test (FCSRT)

  • Logical Memory IIa Delayed Recall (LM)

  • Digit Symbol Substitituion Test (DSST)

  • Mini-Mental State Examination (MMSE)

This function generates two modified versions of PACC scores based on ADNI data. FCSRT is not used in ADNI, so we use the Delayed Recall portion of the Alzheimer's Disease Assessment Scale (ADAS) as a proxy. Score mPACCdigit uses the DSST when available (ADNI1). mPACCtrailsB uses (log transformed) Trails B as a proxy for DSST. Raw component scores standardized according to the mean and standard deviation of baseline scores of ADNI subjects with normal cognition to create Z scores for each component (Z=(raw - mean( The Z scores are reoriented if necessary so that greater scores reflect better performance. The composite is the sum of these Z scores.

Missing components: At least two components must be present to produce a score. If more than two components are missing, the PACC will be NA.


  • Donohue MC, et al. The Preclinical Alzheimer Cognitive Composite: Measuring Amyloid-Related Decline. JAMA Neurol. 2014;71(8):961–970. doi:10.1001/jamaneurol.2014.803

  • Donohue MC, Sperling RA, Petersen R, Sun C, Weiner MW, Aisen PS, for the Alzheimer’s Disease Neuroimaging Initiative. Association Between Elevated Brain Amyloid and Subsequent Cognitive Decline Among Cognitively Normal Persons. JAMA. 2017;317(22):2305–2316.

See also