Equivalence of the FCSRT and RAVLT to detect medial Temporal lobe atrophy and tauopathy

In AD research, word-learning tests are often used interchangeably despite using distinct learning protocols. This study verified the equivalence of the Rey Auditory Learning Test (RAVLT) and Free and Cued Selective Reminding Test (FCSRT) when investigating medial temporal lobe (MTL) changes and AD-related tau pathology. We obtained the FCSRT and RAVLT immediate and delayed free recalls from 286 participants aged 51+. We segmented MTL regions to obtain the volume and tau-PET signal using the [¹⁸F]MK-6240 tracer. Tau-PET Braak stages and plasma p-tau₁₈₁, p-tau₂₁₇ and p-tau₂₃₁ quantifications were also acquired. Using partial correlations, we compared FCSRT to RAVLT as well as their ability to detect the cognitive status the AD biomarker results. FCSRT and RAVLT were strongly correlated to one another (R > 0.779), with similar differentiation of cognitively impaired and cognitively unimpaired individuals (AUC > 0.810). Both predicted MTL volume, MTL tau-PET accumulation, plasma p-tau and Braak stages similarly, with no significant effect size differences. For all tests, a subtle memory impairment was found at tau-PET Braak stage III, while more robust impairments were found at stage IV onward. Despite their differences, both the RAVLT and FCSRT are equivalent at detecting AD-related pathology and symptoms, suggesting that, in these contexts, they may be used interchangeably. However, these results should be interpreted with care since the sample is not representative of a global population.