Cultural validity of cognitive markers for Alzheimer’s disease (AD): Evidence for global strategies

Abstract

AbstractBackgroundAvailability of culture‐free cognitive tests with marker properties for AD has proved a barrier to global harmonization strategies. The European Neurodegenerative Diseases Working Group suggested that the Short‐Term Memory Binding Test (STMBT) and the Free and Cued Selective Reminding Test (FCSRT) are useful tests for the early detection of AD (Costa et al., 2017). Yassuda et al. (2019) showed that STMB is insensitive to age and education among healthy Brazilian adults. Parra et al. (2019) suggested that these tests should enter global strategies to aid the early detection of AD. Evidence is still needed to ascertain that such a validity translates to the assessment of affected individuals from underrepresented populations. The current study aimed to shed new light on such an outstanding question.MethodsWe recruited 64 healthy controls (HC), 60 patients with Mild Cognitive Impairment (MCI), and 63 patients with mild AD from Lima, regional area health clinics (DIRESA) between 06/2018‐05/2019. They were all illiterate. We considered Illiterate individuals who (1) attended no school or were enrolled for less than one year and (2) could not read or write (a booklet was given which showed a simple sentence). We assessed them with the STMBT, the visual FCSRT, and a brief clinical‐neuropsychological protocol.ResultsThe assessment confirmed the healthy (CDR=0.0, pFAQ=2.2, BDI=5.9), MCI (CDR=0.5, pFAQ=3.7, BDI=6.2), and dementia (CDR=1.3, pFAQ=16.5, BDI=7.2) status of our groups. Significant between‐group differences were found with both the STMBT (F(2,184)=590.1, p<0.001) and Free Recall during the visual FCSRT (F(2,184)=3936.2, p<0.001), with HC>>>MCI>>>AD. ROC analysis with STMB revealed AUC=0.98 for HC vs. MCI, AUC=1.00 for HC vs. AD, and AUC=0.97 for MCI vs. AD. For the visual FCSRT, an AUC=1.00 was found for HC vs (MCI & AD), and AUC=0.99 for MCI vs AD.ConclusionThe two cognitive markers recently recommended for harmonisation of neuropsychological assessment in neurodegenerative dementias in Europe seem suitable to support such practices in illiterate populations. Parra et al. (2019) recently suggested that only global strategies will help meet global challenges. Here we provide evidence of cognitive markers for AD that can reliably enter such strategies.