Treating cognitive impairment is a holy grail of modern clinical neuroscience. In the past few years, non-invasive brain stimulation is increasingly emerging as a therapeutic approach to ameliorate performance in patients with cognitive impairment and as an augmentation approach in persons whose cognitive performance is within normal limits. In patients with Alzheimer’s disease, better understanding of brain connectivity and function has allowed for the development of different non-invasive brain stimulation protocols. Recent studies have shown that transcranial stimulation methods enhancing brain plasticity with several modalities have beneficial effects on cognitive functions. Amelioration has been shown in preclinical studies on behaviour of transgenic mouse models for Alzheimer’s pathology and in clinical studies with variable severity of cognitive impairment. While the field is still grappling with issues related to the standardization of target population, frequency, intensity, treatment duration and stimulated region, positive outcomes have been reported on cognitive functions and on markers of brain pathology. Here we review the most encouraging protocols based on repetitive transcranial magnetic stimulation, transcranial direct current stimulation, transcranial alternating current stimulation, visual-auditory stimulation, photobiomodulation and transcranial focused ultrasound, which have demonstrated efficacy to enhance cognitive functions or slow cognitive decline in patients with Alzheimer’s disease. Beneficial non-invasive brain stimulation effects on cognitive functions are associated with the modulation of specific brain networks. The most promising results have been obtained targeting key hubs of higher-level cognitive networks, such as the frontal-parietal network and the default mode network. The personalization of stimulation parameters according to individual brain features sheds new light on optimizing non-invasive brain stimulation protocols for future applications.

中文翻译：

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阿尔茨海默病中无创脑刺激的新兴领域


治疗认知障碍是现代临床神经科学的圣杯。在过去的几年里，无创脑刺激越来越多地成为一种改善认知障碍患者表现的治疗方法，以及作为认知能力在正常范围内的人的增强方法。在阿尔茨海默病患者中，对大脑连接和功能的更好理解允许开发不同的非侵入性脑刺激方案。最近的研究表明，通过多种方式增强大脑可塑性的经颅刺激方法对认知功能有有益的影响。在关于转基因小鼠模型治疗阿尔茨海默病病理行为的临床前研究和具有不同严重程度的认知障碍的临床研究中，已显示出改善。虽然该领域仍在努力解决与目标人群、频率、强度、治疗持续时间和刺激区域的标准化相关的问题，但已报告了认知功能和脑病理标志物的积极结果。在这里，我们回顾了基于重复经颅磁刺激、经颅直流电刺激、经颅交流电刺激、视觉听觉刺激、光生物调节和经颅聚焦超声的最令人鼓舞的方案，这些方案已被证明可以增强阿尔茨海默病患者的认知功能或减缓认知能力下降。对认知功能的有益非侵入性脑刺激作用与特定脑网络的调节有关。 最有希望的结果已经针对高级认知网络的关键枢纽，如额顶网络和默认模式网络。根据个体大脑特征对刺激参数进行个性化，为优化非侵入性脑刺激方案以用于未来的应用提供了新的思路。