Multi-trial Free Recall for Evaluating Memory

Objective: Much of our knowledge concerning the neural basis of human memory derives from lab-based verbal recall tasks. Outside of the lab, clinicians use validated and normed neuropsychological tests to assess patients' memory function and to evaluate clinical interventions. Here we sought to establish the clinical validity of multi-trial free recall of semantically organized and unrelated word lists. Methods: We compared memory performance in multi-trial free recall tasks with the Rey Auditory Verbal Learning Task (RAVLT) and the California Verbal Learning Task (CVLT), two common neuropsychological tests aimed at evaluating memory function in clinical settings. We compared predictive validity between the tasks by (a) evaluating deficits in a patient sample, (b) examining age-related declines in memory. We also compared test-retest reliability, convergent validity and the emergence of common recall dynamics between the tasks. Results: We demonstrate that both laboratory free recall tasks have better predictive validity, as well as test-retest reliability, than the established neuropsychological tests. We further show that all tasks have good convergent validity and reveal core memory processes, including temporal and semantic organization, but we demonstrate the benefits of repeated trials for evaluating the dynamics of memory search and their neuropsychological sequelae. Conclusion: The results provide evidence for the clinical validity of lab-based multi-trial free recall tasks and highlight their psychometric benefits over neuropsychological measures. Based on these results, we discuss the need to bridge the gap between clinical understanding of putative mechanisms underlying memory disorders and neuroscientific findings obtained using lab-based free recall tasks