Aschenbrenner Andrew J, Balota David A, Gordon Brian A, Ratcliff Roger, Morris John C
Department of Psychology, Washington University in St. Louis.
Department of Radiology, Washington University in St. Louis.
Neuropsychology. 2016 Feb;30(2):225-38. doi: 10.1037/neu0000222.
A family history of Alzheimer's disease (AD) increases the risk of developing AD and can influence the accumulation of well-established AD biomarkers. There is some evidence that family history can influence episodic memory performance even in cognitively normal individuals. We attempted to replicate the effect of family history on episodic memory and used a specific computational model of binary decision making (the diffusion model) to understand precisely how family history influences cognition. Finally, we assessed the sensitivity of model parameters to family history controlling for standard neuropsychological test performance.
Across 2 experiments, cognitively healthy participants from the Adult Children Study completed an episodic recognition test consisting of high- and low-frequency words. The diffusion model was applied to decompose accuracy and reaction time (RT) into latent parameters which were analyzed as a function of family history.
In both experiments, individuals with a family history of AD exhibited lower recognition accuracy and this occurred in the absence of an apolipoprotein E (APOE) ε4 allele. The diffusion model revealed this difference was due to changes in the quality of information accumulation (the drift rate) and not differences in response caution or other model parameters. This difference remained after controlling for several standard neuropsychological tests.
These results confirm that the presence of a family history of AD confers a subtle cognitive deficit in episodic memory as reflected by decreased drift rate that cannot be attributed to APOE. This measure may serve as a novel cognitive marker of preclinical AD.
阿尔茨海默病（AD）家族史会增加患AD的风险，并可能影响已确立的AD生物标志物的积累。有证据表明，家族史甚至会影响认知正常个体的情景记忆表现。我们试图重现家族史对情景记忆的影响，并使用一种特定的二元决策计算模型（扩散模型）来精确了解家族史如何影响认知。最后，我们评估了在控制标准神经心理测试表现的情况下，模型参数对家族史的敏感性。
在2个实验中，来自成年子女研究的认知健康参与者完成了一项由高频和低频单词组成的情景识别测试。应用扩散模型将准确率和反应时间（RT）分解为潜在参数，并将其作为家族史的函数进行分析。
在两个实验中，有AD家族史的个体表现出较低的识别准确率，且这一情况在没有载脂蛋白E（APOE）ε4等位基因的情况下也存在。扩散模型显示，这种差异是由于信息积累质量（漂移率）的变化，而非反应谨慎程度或其他模型参数的差异。在控制了几项标准神经心理测试后，这种差异仍然存在。
这些结果证实，AD家族史的存在会导致情景记忆出现细微的认知缺陷，表现为漂移率降低，且这不能归因于APOE。这一指标可能作为临床前AD的一种新型认知标志物。
