Task decomposition analysis of intertrial free recall performance on the rey auditory verbal learning test in normal aging and Alzheimer's disease

Task decomposition provides supplementary data that complement traditionall y computed performance indexes of multi-trial list learning. Both tradition al and decomposition approaches can be combined to permit a thorough assess ment of multiple aspects of learning and memory in patients with memory imp airment. We applied task decomposition to investigate the relative roles of acquisition and consolidation in mediating the multi-trial learning defici t in patients with Alzheimer's disease. This goal was accomplished by decom posing recall performance across the five study-and-test trials of the Rey Auditory Verbal Learning Tests into measures that presumably tap intertrial acquisition and intertrial consolidation. As compared to matched controls, patients diagnosed with mild Alzheimer's disease showed lower gained acces s across trials, indicating that Alzheimer' s disease impairs the ability t o produce a stable memory representation of new material in long-term memor y. Additionally, patients with Alzheimer's disease manifested higher lost a ccess, which suggests that deficient consolidation leading to rapid intertr ial forgetting also contributes to their poor learning. We argue that analy tically decomposing learning curves will help both in uncovering the cognit ive processes that underlie disease-related learning deficits in persons wi th memory disorders and can help to characterize potential areas for remedi ation.