Background: Cognitive Training (CT) has demonstrated some benefits to cognitive and psychosocial function in Mild Cognitive Impairment (MCI) and early dementia, but the certainty related to those findings remains unclear. Therefore, understanding the mechanisms by which CT improves cognitive functioning may help to understand the relationships between CT and cognitive function.

The purpose of this review was to identify the evidence for neuroimaging outcomes in studies of CT in MCI and early Alzheimer’s Disease (AD).

Methods: Medline, Embase, Web of Science, PsycINFO, CINAHL, and The Cochrane Library were searched with a predefined search strategy, which yielded 1778 articles. Studies were suitable for inclusion where a CT program was used in patients with MCI or AD, with a structural or functional Magnetic Resonance Imaging (MRI) outcome. Studies were assessed for quality using the Downs and Black criteria.

Results: A total of 19 studies met the inclusion criteria. Quality of the included studies was variable and there was significant heterogeneity for studies included in this review. Task activation was generally increased post-training, but functional connectivity was both increased and decreased after training. Results varied by diagnosis, type of CT program, and brain networks examined. No effects were seen on hippocampal volumes post-training, but cortical thickening and increased grey matter volumes were demonstrated.

Conclusions: CT resulted in variable functional and structural changes in dementia, and conclusions are limited by heterogeneity and study quality. Larger, more robust studies are required to correlate these findings with clinical benefits from CT.

中文翻译：

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轻度认知障碍和早期阿尔茨海默病认知训练研究中的神经影像学结果：系统评价。

背景：认知训练 (CT) 已证明对轻度认知障碍 (MCI) 和早期痴呆症的认知和心理社会功能有一些好处，但与这些发现相关的确定性仍不清楚。因此，了解CT改善认知功能的机制可能有助于理解CT与认知功能之间的关系。

本综述的目的是确定 MCI 和早期阿尔茨海默病 (AD) 中 CT 研究中神经影像学结果的证据。

方法：使用预定义的搜索策略对 Medline、Embase、Web of Science、PsycINFO、CINAHL 和 Cochrane 图书馆进行搜索，共检索到 1778 篇文章。将 CT 程序用于 MCI 或 AD 患者并具有结构性或功能性磁共振成像 (MRI) 结果的研究适合纳入。使用 Downs 和 Black 标准评估研究的质量。

结果：共有19项研究符合纳入标准。纳入研究的质量参差不齐，本综述纳入的研究存在显着异质性。任务激活通常在训练后增加，但功能连接在训练后增加和减少。结果因诊断、CT 程序类型和检查的大脑网络而异。训练后对海马体积没有影响，但证实了皮质增厚和灰质体积增加。

结论：CT 导致痴呆的功能和结构变化可变，结论受到异质性和研究质量的限制。需要更大规模、更稳健的研究来将这些发现与 CT 的临床益处相关联。