Research Hotspots and Frontiers of Transcranial Direct Current Stimulation in Stroke: A Bibliometric Analysis

Exploring the Research Landscape of Transcranial Direct Current Stimulation in Stroke: A Bibliometric Review

Transcranial direct current stimulation (tDCS) has gained significant attention as a potential therapeutic tool in stroke rehabilitation, promoting neuroplasticity and enhancing motor and cognitive recovery. Despite growing research, the field's evolution and key trends remain underexplored. This study aims to perform a bibliographic analysis of publications related to tDCS and stroke rehabilitation to assess the growth of the field. Published literature was searched in PubMed and Web of Science (WOS) on 10 December 2024. We used the keywords "transcranial direct current stimulation" and "stroke" to collect studies without any time limitation. Articles found in WOS were used to get trends, and a search from PubMed was used to analyze co-occurrences in VOSviewer, version 1.6.20 (Centre for Science and Technology Studies, Leiden University, the Netherlands). A total of 1,598 articles were found in WOS, and 1,300 were found in PubMed. As there was overlapping of subject categories, countries, and affiliations, the total number differed in calculating the percentages. The analysis revealed significant growth in publications on tDCS and stroke rehabilitation, peaking at 137 publications in 2022. Most studies focus on neuroscience (860, or 30.6%), clinical neurology (562, or 20%), and rehabilitation (244, or 8.68%). The United States leads contributions (519, or 22.4%), followed by Germany (249, or 10.7%) and China (179, or 7.7%). Publications are concentrated among major publishers like Elsevier (358, or 22.4%) and key journals such as Brain Stimulation and Frontiers in Human Neuroscience. English dominates as the primary language (1,572, or 98.37%). Research emphasizes tDCS's role in motor recovery and brain plasticity in stroke rehabilitation. This bibliometric analysis highlights a substantial and growing interest in tDCS for stroke rehabilitation, with a steady increase in publications. The focus of research predominantly lies in neuroscience, clinical neurology, and rehabilitation, reflecting the central role of tDCS in advancing stroke recovery and brain plasticity. The concentration of publications among major publishers and journals underscores the prominence of specific platforms in disseminating tDCS research. More research from developing countries is needed to achieve a balanced geographical diversity on this topic.

Dual-tDCS combined with sensorimotor training promotes upper limb function in subacute stroke patients: A randomized, double-blinded, sham-controlled study

BACKGROUND

Dual transcranial direct current stimulation (tDCS) over the bilateral primary somatosensory cortex (PSC) has potential benefits in stroke. In addition, compared with traditional rehabilitation training, sensorimotor training can significantly improve the sensorimotor function of patients. However, the efficacy of dual-tDCS combined with sensorimotor training in patients with subacute stroke is unknown.

OBJECTIVE

To assess whether dual-tDCS may enhance the efficacy of sensorimotor training on the upper limb functions in patients with subacute stroke. In addition, this study aims to explore the potential clinical mechanism of this combination therapy.

METHODS

We randomized 52 individuals with first-ever, unilateral subcortical stroke into the experimental group (n = 26) and the control group (n = 26). Patients in the experimental group received 20 min of dual-tDCS over the PSC and 40 min of sensorimotor training each session, while patients in the control group received sham dual-tDCS. The treatment cycle was a 1-h session of therapy each day, 5 days per week for 4 weeks. The Fugl-Meyer Assessment of Upper Extremity (FMA-UE) subscale, Action Research Arm Test (ARAT), Box and Block test (BBT), Erasmus MC revised Nottingham sensory assessment scale (Em-NSA), Neurometer sensory nerve quantitative detector (CPT), the Barthel index (BI), and Hospital Anxiety and Depression Scale (HADS) were used to assess upper limb function, activities of daily living (ADL), and mental health before and after the 4-week treatment period. In addition, functional near-infrared spectroscopy (fNIRS) was used to explore potential clinical brain mechanisms.

RESULTS

Both groups showed significant improvement in all clinical scales (All p < 0.05) after treatment. Compared with sham-tDCS plus sensorimotor training, active dual-tDCS coupled with sensorimotor training can significantly improve the FMA-UE, ARAT, Em-NSA-Stereognosis, and CPT-2K Hz. In addition, dual-tDCS combined with sensorimotor training can significantly activate the left pre-Motor and supplementary motor cortex (PM-SMC) and enhance the functional connection between the left somatosensory association cortex (SAC) and RPM-SMC. Furthermore, the difference of FMA-UE in the experimental group was positively correlated with the functional connectivity of RPM-SMC-LSAC (r = 0.815, p < 0.001).

CONCLUSION

Dual-tDCS over the PSC combined with sensorimotor training can improve upper limb sensory and motor dysfunction, enhance ADL, and alleviate depression and anxiety for subacute stroke patients. Our results indicated that RPM-SMC-LSAC may be potential therapeutic targets for dual-tDCS in upper limb rehabilitation on stroke.

Global trends and research hotspots of stroke and magnetic resonance imaging: A bibliometric analysis

BACKGROUND

In this study, we used CiteSpace and VOSviewer to create a bibliometric visualization of research papers relating to stroke and magnetic resonance imaging (MRI) between 2000 and 2022. To fully understand the trends and hotspots in MRI and stroke research and provide new perspectives for future studies.

METHODS

The Web of Science Core Collection was selected as the source of data for this paper. Using CiteSpace and VOSviewer, publications were analyzed for authors, countries, institutions, journals, references, and keywords.

RESULTS

We found 1423 papers after searching and removing duplicates, which indicated an upward trend over the previous 23 years. Fiebach J.B. is the most published author (21 publications), Hacke W. is the most cited author (213 citations), and the United States (449 publications) and Harvard University (86 publications) are the most prolific nations and institutions. Stroke is the journal with the most co-citations (1275) and the most papers (171) published. The most representative reference was the 1995 article by Marler et al, which received 115 citations and had the top 3 co-occurring keywords: stroke, magnetic resonance imaging, and MRI. The article by Nogueria et al showed the strongest citation burst at the end of 2022 (strength = 17.32). High-frequency keywords in recent years are time, association, functional connectivity, thrombectomy, and rehabilitation.

CONCLUSION

This study provides a scientific perspective on stroke and MRI research, provides valuable information for researchers to understand the current status of research, hotspots, and trends, and guides future research directions.