Cheng Lin, Tu Min-Chien, Huang Wen-Hui, Hsu Yen-Hsuan
Department of Psychiatry, Hsinchu MacKay Memorial Hospital, MacKay Medical Foundation, The Presbyterian Church in Taiwan, Hsinchu, Taiwan.
Department of Neurology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, Taiwan.
Gerontology. 2021;67(6):718-728. doi: 10.1159/000514869. Epub 2021 Apr 14.
Prospective memory (PM) is a multiphasic cognitive function important for autonomy and functional independence but is easily disrupted by pathological aging processes. Through cognitive simulation of perceptual experiences, mental imagery could be an effective compensatory strategy to enhance PM performance. Nevertheless, relevant research in individuals with amnestic mild cognitive impairment (MCI) has been limited, and the underlying mechanism of the therapeutic effect has not been sufficiently elucidated. The present study aimed to examine complex PM performances and the effect of mental imagery on each phase in older adults with MCI and to investigate the underlying cognitive mechanism from a process perspective.
Twenty-eight MCI and 32 normal aging controls completed a seminaturalistic PM task, in addition to a series of neuropsychological tests. Participants from each group were randomly assigned to a mental imagery condition or a standard repeated encoding condition before performing the PM task. Four indices were used to measure performance in the intention formation, intention retention, intention initiation, and intention execution phases of PM. Performances in each phase was compared between the 2 diagnostic groups and the 2 instruction conditions.
The MCI group performed worse than the normal aging group in the intention formation and intention retention phases. The participants in the mental imagery condition performed significantly better than those in the standard condition during the intention formation, intention retention, and intention execution phases, regardless of the diagnostic group. Moreover, there was a significant interaction between the group and condition during intention retention, showing that people with MCI benefited even more from mental imagery than normal aging in this phase. Performance in the intention retention phase predicted performance in the intention initiation and intention execution phases.
PM deficits in MCI mainly manifest during planning and retaining intentions. Mental imagery was able to promote performance in all but the initiation phase, although a trend for improvement was observed in this phase. The effects of mental imagery may be exerted in the intention retention phase by strengthening the PM cue-action bond, thereby facilitating the probability of intention initiation and bolstering fidelity to the original plan during intention execution.
前瞻性记忆（PM）是一种多阶段认知功能，对自主性和功能独立性很重要，但容易受到病理性衰老过程的干扰。通过对感知体验的认知模拟，心理意象可能是提高前瞻性记忆表现的一种有效补偿策略。然而，针对遗忘型轻度认知障碍（MCI）个体的相关研究有限，治疗效果的潜在机制尚未得到充分阐明。本研究旨在考察MCI老年人的复杂前瞻性记忆表现以及心理意象对各阶段的影响，并从过程角度探究潜在的认知机制。
28名MCI患者和32名正常衰老对照者除完成一系列神经心理学测试外，还完成了一项半自然前瞻性记忆任务。每组参与者在执行前瞻性记忆任务前被随机分配到心理意象条件组或标准重复编码条件组。使用四个指标来衡量前瞻性记忆在意图形成、意图保持、意图启动和意图执行阶段的表现。比较两个诊断组和两种指导条件下各阶段的表现。
MCI组在意图形成和意图保持阶段的表现比正常衰老组差。无论诊断组如何，心理意象条件组的参与者在意图形成、意图保持和意图执行阶段的表现均显著优于标准条件组的参与者。此外，在意图保持阶段，组和条件之间存在显著交互作用，表明MCI患者在这一阶段从心理意象中获益比正常衰老者更多。意图保持阶段的表现预测了意图启动和意图执行阶段的表现。
MCI中的前瞻性记忆缺陷主要表现在计划和保持意图期间。心理意象能够促进除启动阶段外所有阶段的表现，尽管在该阶段观察到有改善趋势。心理意象的作用可能是通过加强前瞻性记忆线索 - 行动联系在意图保持阶段发挥的，从而促进意图启动的可能性，并在意图执行期间增强对原始计划的忠诚度。
