Utility of Cognitive Abilities Screening Instrument (CASI) subscores in detecting early impairment in autosomal dominant Alzheimer’s disease (ADAD)

Abstract

AbstractBackgroundPrior research among patients with autosomal dominant Alzheimer’s Disease (ADAD) has identified early cognitive changes 10‐20 years before formal dementia diagnosis. ADAD provides a model of Alzheimer’s disease (AD) with a relatively predictable onset and with fewer age‐related comorbidities, and as such, may aid in identifying presymptomatic stages of cognitive change for early AD detection. The CASI is a comprehensive screening tool for dementia with multilingual adaptations and may be useful in identifying early cognitive changes among those with or at risk of ADAD.MethodWe examined whether subscales of the Cognitive Abilities Screening Instrument (CASI) could identify early cognitive changes in ADAD as well as the effects of test language (English or Spanish), education, and acculturation on CASI subscales. 141 persons (96 mutation carriers [MC], 45 noncarriers [NC]) with or at risk for inheriting PSEN1/2 or APP mutations completed the CASI. Linear mixed‐effect models were used to examine the effects of adjusted age, mutation status, mutation type (APP or PSEN), test language, education, and acculturation on the 9 CASI subscales.ResultMCs performed significantly worse on CASI subscales than NCs (ps<.001). Adjusted age (βs = ‐.29— ‐.09), mutation status (βs = ‐2.62—‐0.09), and adjusted age x mutation status (βs = ‐.29— ‐0.09) significantly predicted Attention (R2 = 0.36), Concentration (R2 = 0.40), Orientation (R2 = 0.53), Short‐Term Memory (R2 = 0.61), Long‐Term Memory (R2 = 0.27), Language (R2 = 0.39), Visuoconstruction (R2 = 0.53), Fluency (R2 = 0.34), and Abstraction/Judgment (R2 = 0.37), all ps <.001. Acculturation significantly predicted Long‐Term Memory (β = .34, p = .03). The effects of acculturation, test language, and education were not significant for any other CASI subscales.ConclusionAdjusted age, mutation status, and an interactive effect between adjusted age and mutation status appear to be important predictors in CASI performance, such that MCs closer to their familial age of dementia diagnosis are more likely to perform worse on the CASI. No subtest emerged as the best predictor of early cognitive changes in MCs. Attention to potential cultural influences on the Long‐Term Memory subtest warrants further research.