Memory and language cognitive data harmonization across the United States and Mexico

INTRODUCTION: We used cultural neuropsychology-informed procedures to derive and validate harmonized scores representing memory and language across population-based studies in the United States and Mexico. METHODS: Data were from the Health and Retirement Study Harmonized Cognitive Assessment Protocol (HRS-HCAP) and the Mexican Health and Aging Study (MHAS) Ancillary Study on Cognitive Aging (Mex-Cog). We statistically co-calibrated memory and language domains and performed differential item functioning (DIF) analysis using a cultural neuropsychological approach. We examined relationships among harmonized scores, age, and education. RESULTS: We included 3170 participants from the HRS-HCAP (Mage = 76.6 [standard deviation (SD): 7.5], 60% female) and 2042 participants from the Mex-Cog (Mage = 68.1 [SD: 9.0], 59% female). Five of seven memory items and one of twelve language items demonstrated DIF by study. Harmonized memory and language scores showed expected associations with age and education. DISCUSSION: A cultural neuropsychological approach to harmonization facilitates the generation of harmonized measures of memory and language function in cross-national studies. HIGHLIGHTS: We harmonized memory and language scores across studies in the United States and Mexico. A cultural neuropsychological approach to data harmonization was used. Harmonized scores showed minimal measurement differences between cohorts. Future work can use these harmonized scores for cross-national studies of Alzheimer's disease and related dementias.