Top 100 cited noninvasive neuromodulation clinical trials

ABSTRACT

Introduction: Transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS) are noninvasive neuromodulation techniques used as therapeutic and research tools for several neuropsychiatric conditions. Given the exponential scientific growth of this field, we aimed to systematically review the most cited clinical trials using TMS or tDCS.

Areas covered: A de-novo keyword search strategy identified and characterized the 100 most-cited trials. Total citation count for the most cited trials was 13,204. Articles were published between 2008 and 2014 in 50 different journals with a median impact factor of 6.52 (IQR 3.37). Almost half of the top cited papers were investigating mechanisms of action in healthy subjects. Most studies were feasibility trials and only five were pivotal trials, including the ones used for recent FDA approval. Seven articles were interlinked with another article by at least 25 citations and eight authors had collaborated with at least one other author.

Expert opinion: Although there has been a significant increase in interest for rTMS and tDCS, most of the cited clinical trials are still small feasibility studies, what reinforced the need for more robust clinical trials (larger samples sizes and effects sizes) to better define clinical effectiveness.

KEYWORDS:

• Bibliometrics
• citation analysis
• neurosciences
• transcranial magnetic stimulation
• transcranial direct current stimulation
• noninvasive brain stimulation
• neuromodulation

Article Highlights

• Exponential growth of the number of publications and clinical applications of tDCS and TMS, mainly due to its potential of enhancing brain plasticity while having few side effects.

• Citation analysis can measure the impact of scientific publications providing a better understanding of specific research field its directions and trends; however, there is lack of such information for the noninvasive neuromodulation field.

• The identification of the 100 most-cited clinical trials using TMS or tDCS by this review aimed to describe and characterize the available literature in neuromodulation over the past 10 years.

• Citation counts might not be a direct measure of scientific quality; however, it is a valid method to identify trends in research. This review provides an overview of the neuromodulation field and its coauthorship network and collaborating authors.

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Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was funded by the National Institutes of Health, grant nos. 1 R01 AT009491-01A1 and 5R01HD082302-02.