Center for Psychophysics, Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India.
Department of Integrative Medicine, National Institute of Mental Health and Neurosciences, Bangalore, India.
Acta Neuropsychiatr. 2021 Oct;33(5):242-253. doi: 10.1017/neu.2021.14. Epub 2021 Apr 30.
Previous studies have examined the effect of transcranial direct current stimulation (tDCS) on the in-vivo concentrations of neuro-metabolites assessed through magnetic resonance spectroscopy (MRS) in neurological and psychiatry disorders. This review aims to systematically evaluate the data on the effect of tDCS on MRS findings and thereby attempt to understand the potential mechanism of tDCS on neuro-metabolites.
The relevant literature was obtained through PubMed and cross-reference (search till June 2020). Thirty-four studies were reviewed, of which 22 reported results from healthy controls and 12 were from patients with neurological and psychiatric disorders.
The evidence converges to highlight that tDCS modulates the neuro-metabolite levels at the site of stimulation, which, in turn, translates into alterations in the behavioural outcome. It also shows that the baseline level of these neuro-metabolites can, to a certain extent, predict the outcome after tDCS. However, even though tDCS has shown promising effects in alleviating symptoms of various psychiatric disorders, there are limited studies that have reported the effect of tDCS on neuro-metabolite levels.
There is a compelling need for more systematic studies examining patients with psychiatric/neurological disorders with larger samples and harmonised tDCS protocols. More studies will potentially help us to understand the tDCS mechanism of action pertinent to neuro-metabolite levels modulation. Further, studies should be conducted in psychiatric patients to understand the neurological changes in this population and potentially unravel the neuro-metabolite × tDCS interaction effect that can be translated into individualised treatment.
先前的研究已经考察了经颅直流电刺激（tDCS）对通过磁共振波谱（MRS）评估的神经代谢物的体内浓度的影响，这些研究涉及神经和精神疾病。本综述旨在系统地评估 tDCS 对 MRS 研究结果的影响，从而尝试理解 tDCS 对神经代谢物的潜在作用机制。
通过 PubMed 和参考文献进行检索（截至 2020 年 6 月）获取相关文献。共综述了 34 项研究，其中 22 项研究结果来自健康对照者，12 项研究结果来自神经和精神疾病患者。
研究证据表明，tDCS 可调节刺激部位的神经代谢物水平，从而转化为行为结果的改变。它还表明，这些神经代谢物的基线水平在一定程度上可以预测 tDCS 后的结果。然而，尽管 tDCS 在缓解各种精神疾病的症状方面显示出有希望的效果，但只有有限的研究报告了 tDCS 对神经代谢物水平的影响。
迫切需要更多的系统研究来检查患有精神/神经疾病的患者，这些研究需要有更大的样本量和更统一的 tDCS 方案。更多的研究将有助于我们理解与神经代谢物水平调节相关的 tDCS 作用机制。此外，应在精神疾病患者中进行研究，以了解该人群中的神经变化，并可能揭示可以转化为个体化治疗的神经代谢物×tDCS 相互作用效应。
