Structured activities to stimulate brain function—that is, cognitive training exercises—are promoted to slow or prevent cognitive decline, including dementia, but their effectiveness is highly debated.

To summarize evidence on the effects of cognitive training on cognitive performance and incident dementia outcomes for adults with normal cognition or mild cognitive impairment (MCI).

Ovid MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and PsycINFO through July 2017, supplemented by hand-searches.

Trials (published in English) lasting at least 6 months that compared cognitive training with usual care, waitlist, information, or attention controls in adults without dementia.

Single-reviewer extraction of study characteristics confirmed by a second reviewer; dual-reviewer risk-of-bias assessment; consensus determination of strength of evidence. Only studies with low or medium risk of bias were analyzed.

Of 11 trials with low or medium risk of bias, 6 enrolled healthy adults with normal cognition and 5 enrolled adults with MCI. Trainings for healthy older adults were mostly computer based; those for adults with MCI were mostly held in group sessions. The MCI trials used attention controls more often than trials with healthy populations. For healthy older adults, training improved cognitive performance in the domain trained but not in other domains (moderate-strength evidence). Results for populations with MCI suggested no effect of training on performance (low-strength and insufficient evidence). Evidence for prevention of cognitive decline or dementia was insufficient. Adverse events were not reported.

Heterogeneous interventions and outcome measures; outcomes that mostly assessed test performance rather than global function or dementia diagnosis; potential publication bias.

In older adults with normal cognition, training improves cognitive performance in the domain trained. Evidence regarding prevention or delay of cognitive decline or dementia is insufficient.

Agency for Healthcare Research and Quality.

刺激大脑功能的结构化活动（即认知训练）可以促进减缓或预防包括痴呆症在内的认知功能下降，但其有效性备受争议。

总结关于认知训练对具有正常认知或轻度认知障碍（MCI）的成年人的认知能力和突发性痴呆结局的影响的证据。

截至2017年7月，Ovid MEDLINE，EMBASE，Cochrane对照试验中央注册簿和PsycINFO，并通过人工搜索得到补充。

持续至少6个月的试验（英语出版）将认知训练与没有痴呆症的成年人的常规护理，候补清单，信息或注意力控制进行了比较。

由第二名审稿人确认的单名审稿人对研究特征的提取；双重审查员偏见风险评估；共识确定证据的力量。仅分析偏倚风险较低或中等的研究。

在11项偏低或中度偏倚风险试验中，有6名健康认知正常的成年人和5名MCI成人。对健康的老年人的培训主要是基于计算机的。那些患有MCI的成年人大多在小组会议中举行。与健康人群的试验相比，MCI试验使用注意力控制的频率更高。对于健康的老年人，训练可提高受训练领域的认知能力，但不能改善其他领域（中等强度的证据）。MCI人群的结果表明，训练对表现没有影响（强度低且证据不足）。预防认知能力下降或痴呆的证据不足。未报告不良事件。

异类干预和结果措施；主要评估测试性能而不是整体功能或痴呆症诊断的结果；潜在的出版偏见。

在具有正常认知的老年人中，训练可提高受训练领域的认知表现。关于预防或延迟认知下降或痴呆的证据不足。

医疗保健研究与质量局。