Research Centre, Institut Universitaire de Gériatrie de Montréal, Montréal, Québec, Canada.
Department of Psychology, Université de Montréal, Montréal, Québec, Canada.
J Alzheimers Dis. 2023;94(3):1047-1056. doi: 10.3233/JAD-230131.
Subjective cognitive decline (SCD) was proposed to identify older adults who complain about their memory but perform within a normal range on standard neuropsychological tests. Persons with SCD are at increased risk of dementia meaning that some SCD individuals experience subthreshold memory decline due to an underlying progression of Alzheimer's disease (AD).
Our main goal was to determine whether hippocampal volume and APOE4, which represent typical AD markers, predict inter-individual differences in memory performance among SCD individuals and can be used to identify a meaningful clinical subgroup.
Neuropsychological assessment, structural MRI, and genetic testing for APOE4 were administered to one hundred and twenty-five older adults over the age of 65 from the CIMAQ cohort: 66 SCD, 29 individuals with mild cognitive impairment (MCI), and 30 cognitively intact controls (CTRLS). Multiple regression models were first used to identify which factor (hippocampal volume, APOE4 allele, or cognitive reserve) best predicted inter-individual differences in a Face-name association memory task within the SCD group.
Hippocampal volume was found to be the only and best predictor of memory performance. We then compared the demographic, clinical and cognitive characteristics of two SCD subgroups, one with small hippocampal volume (SCD/SH) and another with normal hippocampal volume (SCD/NH), with MCI and CTRLS. SCD/SH were comparable to MCI on neuropsychological tasks evaluating memory (i.e., test of delayed word recall), whereas SCD/NH were comparable to CTRLS.
Thus, using hippocampal volume allows identification of an SCD subgroup with a cognitive profile consistent with a higher risk of conversion to AD.
主观认知下降（SCD）被提出是为了识别那些抱怨自己记忆力下降但在标准神经心理学测试中表现正常的老年人。有 SCD 的人患痴呆症的风险增加，这意味着一些 SCD 患者由于阿尔茨海默病（AD）的潜在进展而经历亚临床记忆下降。
我们的主要目标是确定海马体积和 APOE4（代表典型的 AD 标志物）是否可以预测 SCD 个体之间记忆表现的个体差异，并可用于识别有意义的临床亚组。
对来自 CIMAQ 队列的 125 名年龄在 65 岁以上的老年人进行神经心理学评估、结构 MRI 和 APOE4 基因检测：66 名 SCD、29 名轻度认知障碍（MCI）和 30 名认知正常对照（CTRLS）。首先使用多元回归模型来确定在 SCD 组内，哪个因素（海马体积、APOE4 等位基因或认知储备）可以最佳预测面孔-名字关联记忆任务中个体间差异。
发现海马体积是记忆表现的唯一最佳预测因素。然后，我们比较了两个 SCD 亚组（海马体积小的 SCD/SH 和海马体积正常的 SCD/NH）与 MCI 和 CTRLS 的人口统计学、临床和认知特征。SCD/SH 在评估记忆的神经心理学任务（即延迟单词回忆测试）上与 MCI 相当，而 SCD/NH 与 CTRLS 相当。
因此，使用海马体积可以识别出一个 SCD 亚组，其认知特征与 AD 转化风险较高一致。
