ABSTRACT
Introduction: Diagnostic classification systems and guidelines posit distinguishing patterns of impairment in Alzheimer's (AD) and vascular dementia (VaD). In our study, we aim to identify which diagnostic instruments distinguish them. Methods: We searched PubMed and PsychInfo for empirical studies published until December 2020, which investigated differences in cognitive, behavioral, psychiatric, and functional measures in patients older than 64 years and reported information on VaD subtype, age, education, dementia severity, and proportion of women. We systematically reviewed these studies and conducted Bayesian hierarchical meta-regressions to quantify the evidence for differences using the Bayes factor (BF). The risk of bias was assessed using the Newcastle-Ottawa-Scale and funnel plots. Results: We identified 122 studies with 17,850 AD and 5,247 VaD patients. Methodological limitations of the included studies are low comparability of patient groups and an untransparent patient selection process. In the digit span backward task, AD patients were nine times more probable (BF = 9.38) to outperform VaD patients (ßg = 0.33, 95% ETI = 0.12, 0.52). In the phonemic fluency task, AD patients outperformed subcortical VaD (sVaD) patients (ßg = 0.51, 95% ETI = 0.22, 0.77, BF = 42.36). VaD patients, in contrast, outperformed AD patients in verbal (ßg = -0.61, 95% ETI = -0.97, -0.26, BF = 22.71) and visual (ßg = -0.85, 95% ETI = -1.29, -0.32, BF = 13.67) delayed recall. We found the greatest difference in verbal memory, showing that sVaD patients outperform AD patients (ßg = -0.64, 95% ETI = -0.88, -0.36, BF = 72.97). Finally, AD patients performed worse than sVaD patients in recognition memory tasks (ßg = -0.76, 95% ETI = -1.26, -0.26, BF = 11.50). Conclusion: Our findings show inferior performance of AD in episodic memory and superior performance in working memory. We found little support for other differences proposed by diagnostic systems and diagnostic guidelines. The utility of cognitive, behavioral, psychiatric, and functional measures in differential diagnosis is limited and should be complemented by other information. Finally, we identify research areas and avenues, which could significantly improve the diagnostic value of cognitive measures.
ABSTRACT
Incentives can decrease performance by undermining intrinsic motivation. How such an interplay of external reinforcers and internal self-regulation influences memory processes, however, is less known. Here, we investigated their interaction on memory performance while learning the meaning of new-words from their context. Specifically, participants inferred congruent meanings of new-words from semantic context (congruent trials) or lack of congruence (incongruent trials), while receiving external feedback in the first or second half of trials only. Removing feedback during learning of congruent word meanings lowered subsequent recognition rates a day later, whereas recognition remained high in the group, which received feedback only in the second half. In contrast, feedback did not substantially alter recognition rates for learning that new-words had no congruent meanings. Our findings suggest that external reinforcers can selectively impair memories if internal self-regulated processes are not already established, but whether they do so depends on what is being learned (specific word-meanings vs. unspecific incongruence). This highlights the relevance of self-regulated learning in education to support stable memory formation.
