The effect of age and years of schooling on CERAD‐MX performance of Mexican preclinical carriers and non‐carriers’ relatives of the V717I APP mutation

Abstract

AbstractBackgroundIn a previous study in a sample of young neurotypical adults (18 to 59 years), we found that years of schooling (YoS) have a greater effect than age on the tasks included in the neuropsychological protocol of the Mexican adaptation of the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD‐MX).MethodThirty‐eight participants (Mage = 31.08 years; MYoS = 8.27 years), from Jalisco State in Mexico, identified as first‐degree relatives of symptomatic autosomal dominant Alzheimer’s disease (ADAD) carriers of the V71 7I APP mutation were divided into two groups, MC (n = 15) and NC (n = 23). Eight CERAD‐MX tasks were used: the Mini‐mental State Examination (MMSE), Semantic Verbal Fluency (SVF), Verbal Boston Naming (VBN), Word List Memory (WLM) with delayed recall (WLD) and recognition (WLR), as well as Constructional Praxis copy (CPC) and recall (CPR). We used z‐scores, then defined random vectors with Sklar’s theorem and a Gaussian dome from simulations of new samples obtained by inverse transform sampling.ResultIn both groups, YoS had a greater positive effect on the MMSE, WLM, WLD z‐scores. In the MC group only, this same effect was evident in the SVF and CPR scores, while in the NC group this effect was seen in the VBN, and CPC z‐scores. Age effect was more pronounced that YoS in MC performance on the CPC, while in NC, on SVF performance.ConclusionFor both groups, YoS has a greater effect than age on several tasks, showing that YoS is a confounding variable when analyzing performance on CERAD‐MX tasks. Moreover, in the MC group, age has a positive effect on CPC task performance suggesting that graphic abilities are not vulnerable to the presence of V717I APP mutation at the preclinical stage.