Transcranial direct current stimulation (tDCS) is accompanied by transient sensations (e.g., tingling, itching, burning), which may affect treatment outcomes or break the blinding of the study protocol. Assessing tolerability and blinding is integral to providing ample evidence of a “real effect” from the applied stimulation and dispelling the possibility of placebo effects. People with Parkinson’s disease (PwPD) endure many motor and non-motor symptoms that might be amenable to tDCS. However, because the disease also affects sensation capabilities, these subjects might report tolerability and blinding differently than other cohorts. Therefore, the purpose of this review was to aggregate the tolerability and blinding reports of tDCS studies in PwPD and recommend a standard tolerability and blinding reporting practice. A literature search of the PubMed and Scopus databases from 1 January 2020 to 1 April 2020 was performed to identify publications that applied tDCS to PwPD. Seventy studies were potentially reviewable, but only 36 (nine with quantitative tolerability reports, 20 with qualitative tolerability reports, and seven that only reported blinding) provided sufficient information to be included in the review. Quantitative information on tDCS tolerability and blinding maintenance in PwPD is scarce, and future reviews and metanalyses should carefully consider the possibility of placebo effects in their included studies.

中文翻译：

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帕金森氏病患者经颅直流电刺激的耐受性和致盲性：一项重要评论。

经颅直流电刺激（tDCS）伴有短暂的感觉（例如刺痛，发痒，灼痛），可能会影响治疗效果或打破研究方案的盲目性。评估耐受性和致盲性是提供充足证据证明所施加刺激产生“真正作用”并消除安慰剂作用可能性的组成部分。帕金森氏病（PwPD）的人会忍受许多可能适用于tDCS的运动和非运动症状。但是，由于该疾病还会影响感觉能力，因此这些受试者的耐受性和致盲性可能不同于其他人群。因此，本次审查的目的是汇总PwPD中tDCS研究的耐受性和致盲性报告，并提出标准的耐受性和致盲性报告实践。从2020年1月1日至2020年4月1日对PubMed和Scopus数据库进行了文献检索，以鉴定将tDCS应用于PwPD的出版物。可能有70项研究可以复审，但只有36项研究（其中9项具有定量耐受性报告，20项有定性耐受性报告，还有7项仅报告盲目性）提供了足够的信息以供评审。关于PwPD中tDCS耐受性和致盲维持的定量信息很稀少，因此在以后的综述和荟萃分析中应仔细考虑安慰剂影响的可能性。20份报告中包含定性的耐受性报告，而7份仅报告了致盲性报告）提供了足够的信息以供审查。关于PwPD中tDCS耐受性和致盲维持的定量信息很稀少，因此在以后的综述和荟萃分析中应仔细考虑安慰剂影响的可能性。20份报告中包含定性的耐受性报告，而7份仅报告了致盲性报告）提供了足够的信息以供审查。关于PwPD中tDCS耐受性和致盲维持的定量信息很稀少，因此在以后的综述和荟萃分析中应仔细考虑安慰剂作用于其纳入研究中的可能性。