The aim of the current study was to test the accuracy of practice effects, that is, improvement in test performance due to repeated neuropsychological evaluations, in identifying patients with amnestic mild cognitive impairment (a-MCI) at greater risk of conversion to Alzheimer disease (AD). For this purpose, we conducted a longitudinal study of 54 patients diagnosed with a-MCI at the first assessment and followed-up for 4 years. During this time, 18 patients converted to AD. Baseline and 6- to 12-month follow-up performances on a large set of neuropsychological tests were analyzed to determine their diagnostic ability to predict later conversion to dementia. Results demonstrate that a lack of practice effects on episodic memory tests is an accurate prognostic indicator of late conversion to AD in a-MCI patients. In fact, even though the performance of both groups was substantially comparable at the baseline evaluation, stable a-MCI patients greatly improved their memory performance at retest after 6 to 12 months; instead, scores of converter a-MCI remained stable or decreased passing from baseline to follow-up. Standardized z-change scores on memory tasks, which were computed as a reliable measure of performance change, classified group membership with very good overall accuracy, which was higher than the classification of converter and stable a-MCIs provided by baseline or follow-up scores. We hypothesize that the lack of practice effects on memory tasks mirrors the early involvement of medial temporal lobe areas in converter a-MCI that are fundamental for the consolidation of new memory traces.

当前研究的目的是测试实践效果的准确性，即由于重复神经心理学评估而提高的测试性能，以识别具有更大转化为阿尔茨海默病风险的遗忘型轻度认知障碍 (a-MCI) 患者。广告）。为此，我们对 54 名在首次评估时被诊断为 a-MCI 的患者进行了纵向研究，并进行了 4 年的随访。在此期间，18 名患者转变为 AD。分析了大量神经心理学测试的基线和 6 至 12 个月的随访表现，以确定它们预测后期转化为痴呆症的诊断能力。结果表明，缺乏对情景记忆测试的实践影响是 a-MCI 患者晚期转化为 AD 的准确预后指标。实际上，尽管在基线评估时两组的表现基本相当，但稳定的 a-MCI 患者在 6 至 12 个月后重新测试时大大改善了他们的记忆表现；相反，转换器 a-MCI 的分数保持稳定或从基线到后续的传递减少。记忆任务的标准化 z 变化分数，计算为性能变化的可靠衡量标准，以非常好的整体准确度对组成员进行分类，高于基线或后续分数提供的转换器和稳定 a-MCI 的分类. 我们假设缺乏对记忆任务的练习影响反映了内侧颞叶区域在转换器 a-MCI 中的早期参与，这是巩固新记忆痕迹的基础。