Langlois Roxane, Joubert Sven, Benoit Sophie, Dostie Valérie, Rouleau Isabelle
Département de psychologie, Université du Québec à Montréal, Montréal, QC, Canada.
Centre de recherche de l'Institut universitaire de gériatrie de Montréal (CRIUGM), Montréal, QC, Canada.
J Alzheimers Dis. 2016;50(4):1023-33. doi: 10.3233/JAD-150722.
Ribot's law refers to the better preservation of remote memories compared with recent ones that presumably characterizes retrograde amnesia. Even if Ribot-type temporal gradient has been extensively studied in retrograde amnesia, particularly in Alzheimer's disease (AD), this pattern has not been consistently found. One explanation for these results may be that rehearsal frequency rather than remoteness accounts for the better preservation of these memories. Thus, the aim of present study was to address this question by studying retrograde semantic memory in subjects with amnestic mild cognitive impairment (aMCI) (n = 20), mild AD (n = 20) and in healthy older controls (HC; n = 19). In order to evaluate the impact of repetition as well as the impact of remoteness, we used a test assessing memory for enduring and transient public events that occurred in the recent and remote past. Results show no clear temporal gradient across time periods (1960-1975; 1976-1990; 1991-2005; 2006-2011), but a better performance was observed in all three groups for enduring compared with transient events. Moreover, although deficits were globally found in both patients groups compared with HC, more specific analyses revealed that aMCI patients were only impaired on transient events while AD patients were impaired on both transient and enduring events. Exploratory analyses also revealed a tendency suggesting preservation of remote transient events in aMCI. These findings are discussed with regards to memory consolidation models.
里博定律是指，与近期记忆相比，远期记忆的保存情况更好，这大概是逆行性遗忘的特征。尽管里博型时间梯度已在逆行性遗忘中得到广泛研究，尤其是在阿尔茨海默病（AD）中，但这种模式并未一直被发现。对这些结果的一种解释可能是，复述频率而非记忆的久远程度能够解释这些记忆保存得更好的原因。因此，本研究的目的是通过研究遗忘型轻度认知障碍（aMCI）患者（n = 20）、轻度AD患者（n = 20）以及健康老年对照者（HC；n = 19）的逆行性语义记忆来解决这个问题。为了评估重复以及记忆久远程度的影响，我们使用了一项测试，该测试评估对近期和远期发生的持续性和短暂性公共事件的记忆。结果显示，在各个时间段（1960 - 1975年；1976 - 1990年；1991 - 2005年；2006 - 2011年）均未发现明显的时间梯度，但与短暂性事件相比，三组在持续性事件上的表现均更好。此外，尽管与HC相比，两个患者组总体上都存在缺陷，但更具体的分析显示，aMCI患者仅在短暂性事件上受损，而AD患者在短暂性和持续性事件上均受损。探索性分析还显示出一种趋势，表明aMCI患者对远期短暂性事件存在记忆保存。我们将结合记忆巩固模型对这些发现进行讨论。
