Transcranial magnetic stimulation (TMS) is a powerful tool to probe in vivo brain circuits, as it allows to assess several cortical properties such as excitability, plasticity and connectivity in humans. In the last 20 years, TMS has been applied to patients with dementia, enabling the identification of potential markers of the pathophysiology and predictors of cognitive decline; moreover, applied repetitively, TMS holds promise as a potential therapeutic intervention.

The objective of this paper is to present a comprehensive review of studies that have employed TMS in dementia and to discuss potential clinical applications, from the diagnosis to the treatment.

To provide a technical and theoretical framework, we first present an overview of the basic physiological mechanisms of the application of TMS to assess cortical excitability, excitation and inhibition balance, mechanisms of plasticity and cortico-cortical connectivity in the human brain. We then review the insights gained by TMS techniques into the pathophysiology and predictors of progression and response to treatment in dementias, including Alzheimer’s disease (AD)-related dementias and secondary dementias. We show that while a single TMS measure offers low specificity, the use of a panel of measures and/or neurophysiological index can support the clinical diagnosis and predict progression.

In the last part of the article, we discuss the therapeutic uses of TMS. So far, only repetitive TMS (rTMS) over the left dorsolateral prefrontal cortex and multisite rTMS associated with cognitive training have been shown to be, respectively, possibly (Level C of evidence) and probably (Level B of evidence) effective to improve cognition, apathy, memory, and language in AD patients, especially at a mild/early stage of the disease. The clinical use of this type of treatment warrants the combination of brain imaging techniques and/or electrophysiological tools to elucidate neurobiological effects of neurostimulation and to optimally tailor rTMS treatment protocols in individual patients or specific patient subgroups with dementia or mild cognitive impairment.

经颅磁刺激 (TMS) 是探测体内大脑回路的强大工具，因为它可以评估多种皮质特性，例如 人类的兴奋性、可塑性和连通性。在过去的 20 年中，TMS 已应用于痴呆症患者，能够识别潜在的 病理生理学标志物和认知衰退的预测因子；此外，通过重复应用，TMS 有望成为一种潜在的治疗干预措施。

本文的目的是全面回顾在痴呆症中使用 TMS 的研究，并讨论从诊断到治疗的潜在临床应用。

为了提供技术和理论框架，我们首先概述了应用 TMS 来评估人脑皮层兴奋性、兴奋和抑制平衡、可塑性机制和皮层皮质连接的基本生理机制。然后，我们回顾了 TMS 技术对痴呆症（包括阿尔茨海默病 (AD) 相关痴呆症和继发性痴呆症）进展和治疗反应的病理生理学和预测因素的见解。我们表明，虽然单个 TMS 测量提供低特异性，但使用一组测量和/或神经生理学指标可以支持临床诊断和预测进展。

在文章的最后一部分，我们讨论了 TMS 的治疗用途。到目前为止，只有左背外侧前额叶皮层的重复 TMS (rTMS) 和与认知训练相关的多部位 rTMS 分别被证明可能（证据级别 C）和可能（证据级别 B）有效改善认知， AD 患者的冷漠、记忆和语言，尤其是在疾病的轻度/早期阶段。此类治疗的临床应用需要结合脑成像技术和/或电生理学工具来阐明神经刺激的神经生物学效应，并在患有痴呆症或轻度认知障碍的个体患者或特定患者亚组中优化调整 rTMS 治疗方案。