Oosterman Joukje M, Heringa Sophie M, Kessels Roy P C, Biessels Geert Jan, Koek Huiberdina L, Maes Joseph H R, van den Berg Esther
a Donders Institute for Brain, Cognition and Behaviour , Radboud University , Nijmegen , The Netherlands.
b Department of Psychiatry, Brain Center Rudolf Magnus , University Medical Center , Utrecht , the Netherlands.
J Clin Exp Neuropsychol. 2017 Apr;39(3):231-241. doi: 10.1080/13803395.2016.1218444. Epub 2016 Sep 12.
Rule induction tests such as the Wisconsin Card Sorting Test require executive control processes, but also the learning and memorization of simple stimulus-response rules. In this study, we examined the contribution of diminished learning and memorization of simple rules to complex rule induction test performance in patients with amnestic mild cognitive impairment (aMCI) or Alzheimer's dementia (AD).
Twenty-six aMCI patients, 39 AD patients, and 32 control participants were included. A task was used in which the memory load and the complexity of the rules were independently manipulated. This task consisted of three conditions: a simple two-rule learning condition (Condition 1), a simple four-rule learning condition (inducing an increase in memory load, Condition 2), and a complex biconditional four-rule learning condition-inducing an increase in complexity and, hence, executive control load (Condition 3).
Performance of AD patients declined disproportionately when the number of simple rules that had to be memorized increased (from Condition 1 to 2). An additional increment in complexity (from Condition 2 to 3) did not, however, disproportionately affect performance of the patients. Performance of the aMCI patients did not differ from that of the control participants. In the patient group, correlation analysis showed that memory performance correlated with Condition 1 performance, whereas executive task performance correlated with Condition 2 performance.
These results indicate that the reduced learning and memorization of underlying task rules explains a significant part of the diminished complex rule induction performance commonly reported in AD, although results from the correlation analysis suggest involvement of executive control functions as well. Taken together, these findings suggest that care is needed when interpreting rule induction task performance in terms of executive function deficits in these patients.
诸如威斯康星卡片分类测试之类的规则归纳测试需要执行控制过程，同时也需要学习和记忆简单的刺激-反应规则。在本研究中，我们考察了遗忘型轻度认知障碍（aMCI）或阿尔茨海默病（AD）患者简单规则学习和记忆能力下降对复杂规则归纳测试表现的影响。
纳入26名aMCI患者、39名AD患者和32名对照参与者。采用一项任务，其中记忆负荷和规则复杂性被独立操控。该任务包括三种条件：简单的双规则学习条件（条件1）、简单的四规则学习条件（导致记忆负荷增加，条件2）以及复杂的双条件四规则学习条件——导致复杂性增加，进而执行控制负荷增加（条件3）。
当必须记忆的简单规则数量增加时（从条件1到条件2），AD患者的表现下降幅度不成比例。然而，复杂性的进一步增加（从条件2到条件3）并未对患者的表现产生不成比例的影响。aMCI患者的表现与对照参与者的表现没有差异。在患者组中，相关分析表明记忆表现与条件1的表现相关，而执行任务表现与条件2的表现相关。
这些结果表明，基础任务规则学习和记忆能力的下降解释了AD患者通常出现的复杂规则归纳表现下降的很大一部分，尽管相关分析结果表明执行控制功能也有参与。综上所述，这些发现表明，在根据这些患者的执行功能缺陷来解释规则归纳任务表现时需要谨慎。
