Abstract
Objective
Data Sources
Study Selection
Data Extraction
Data Synthesis
Conclusions
Keywords
List of abbreviations:
CI (confidence interval), PEDro (Physiotherapy Evidence Database), SMD (standardized mean difference), tDCS (transcranial direct current stimulation)Methods
Search strategy
Selection criteria
Inclusion criteria
Exclusion criteria
Process of identification
Data extraction
Study | Country | Stroke Type | Sample Size N1/N2 | Mean Age (y) n1/n2 | Time Post Stroke (mo) | Other Interventions | Stimulation Site | Dosage | Duration of Treatment | Main OutcomeMeasure |
---|---|---|---|---|---|---|---|---|---|---|
Kumar et al 25 | US | Unilateral hemispheric ischemic stroke | 7/7 | 70/79.7 | 0.13/0.11 | Concurrent standardized swallowing maneuvers | Anodal to unaffected hemisphere Pharyngeal motor cortex | 2 mA | 30 min/5 d | DOSS |
Yang et al 26 | South Korea | Unilateral cerebral apoplexy | 7/9 | 70.57/ 70.44 | 0.90/0.84 | compensatory methods, behavioral maneuvers oromotor exercise, thermal tactile stimulation | Anodal to affected hemisphere Pharyngeal motor cortex | 1 mA | 20 min/10 d | FDS |
Shigematsu et al 27 | Japan | Stroke | 10/10 | 64.7/66.9 | 3.02/3.22 | Ingestion training, indirect therapy, pushing exercises, supraglottic swallowing, shaker exercise, et al | Anodal to affected hemisphere Pharyngeal motor cortex | 1 mA | 20 min/10 d | DOSS |
Yuan et al 28 | China | Cerebellar and pontine arm apoplexy | 15/15 | 57.4/60.7 | 1.95/1.92 | Peripheral percutaneous electrical stimulation therapy | Anodal to body surface projection area of left/right cerebellar hemispheres | 1 mA | 20 min/20 times | MMASA |
Ahn et al 29 | South Korea | Unilateral cerebral apoplexy | 13/13 | 66.38/61.61 | 11.62/12.27 | Compensatory methods, behavioral maneuvers oromotor exercise, thermal tactile stimulation | Anodal to unaffected hemisphere Pharyngeal motor cortex | 1 mA | 20 min/10 d | DOSS |
Wang et al 30 | China | Unilateral cerebral apoplexy | 12/12 | 64.1/63.7 | 1.65/1.59 | Peripheral percutaneous electrical stimulation therapy | Anodal to affected hemisphere Pharyngeal sensorimotor cortex | 1mA | 20 min/ 20 times | MMASA |
He et al 31 | China | Unilateral cerebral apoplexy | a/b/c 7/7/8 | a/b/c 62.29/61.86/60.25 | a/b/c 1.62/1.8/1.98 | Neuromuscular electrical stimulation, ingestion training, motor and sensory training, breath training | a: Anodal to unaffected hemisphere Pharyngeal sensorimotor cortex; b: Anodal to affected hemisphere Pharyngeal sensorimotor cortex | 1.4 mA | 20 min/10 d | MMASA |
Pingue et al 32 | Italy | Unilateral cerebral apoplexy | 20/20 | 68.5/63.5 | conventional swallowing rehabilitation therapy | Anodal to affected hemisphere Pharyngeal motor cortex, Cathodal to unaffected hemisphere Pharyngeal motor cortex | 2mA | 30 min/ 10 days | DOSS | |
Wang et al 33 | China | Basal ganglia apoplexy | 20/20 | 60.8/64.8 | 1.60/1.71 | Swallowing training, glottic closure training, feeding training | Anodal to unaffected hemisphere Pharyngeal cortex | 1.5 mA | 20 min/10 d | MMASS |
Suntrup et al 34 | Germany | Acute ischemic stroke | 30/29 | 67.3/68.9 | 0.16/0.16 | Swallowing exercises | Anodal to unaffected hemisphere Pharyngeal cortex | 1 mA | 20 min/4 d | FOIS |
Wang et al 35 | China | Brainstem stroke | 14/14 | 62.00/ 61.43 | 2.25/2.22 | Catheter balloon dilatation and conventional swallowing therapy | Anodal to the bilateral hemispheres esophageal cortical area | 1 mA | 20 min/20 d | FOIS |
Chen et al 36 | China | Unilateral cerebral apoplexy | 41/43 | 56.32 /54.31 | 3.21/3.22 | Routine swallowing rehabilitation training, motor and sensory training, Mendelssohn swallowing and feeding training | Anodal to affected hemisphere projection area of oropharyngeal cortex | 1.2 mA | 20 min/10 d | MMASA |
Li et al 37 | China | Brainstem stroke | 24/23 | 63.38/62.87 | 1.08/0.70 | Basic treatment, swallowing rehabilitation training, acupuncture therapy | Anodal to sensory area of oropharyngeal cortex | 1.4 mA | 20 min/15 d | VFSS |
Mao et al 38 | China | Brainstem stroke | 20/20 | 62.25/59.8 | 3.60/3.25 | Routine swallowing rehabilitation training, motor and sensory training, breath training, external laryngeal electrical stimulation, balloon dilatation | Anodal to unaffected hemisphere Pharyngeal sensorimotor cortex | 1.6 mA | 20 min/48 d | DOSS |
Yang et al 39 | China | Stroke with bulbar paralysis | a: 30/30 b: 30/30 | b: 59.10/54.93 a: 60.3/59.7 | b: 1.24/1.35 a: 1.30/1.19 | Cold pharyngeal stimulation and empty swallowing, pronunciation training, tongue aspirator training, vibration training, neuromuscular electrical stimulation | Anodal to affected functional regions of the brain associated with the mouth and tongue | 1-2 mA | 20 min/12 d | FOIS |
Liu et al 40 | China | Unilateral cerebral apoplexy | 25/25 | 54.92/55.82 | 2 wk-3mo | Cold stimulation, soft palate lifting training, feeding training | Anodal to affected projection area of oropharyngeal cortex | 1.2 mA | 20 min/10 d | VFSS |
Quality assessment
Statistical analyses
The Cochrane Collaboration. Review Manager. Available at: https://training.cochrane.org. Accessed September 21, 2020.
Higgins JPT, Thomas J, Chandler J, et al, editors. Cochrane handbook for systematic reviews of interventions version 6.1 (updated September 2020). Available at: www.training.cochrane.org/handbook. Accessed April 15, 2021.
Results
Search results
Thomson ResearchSoft. Endnote. Available at: https://endnote.com. Accessed April 15, 2021.

Quality assessment



Description of studies
Study characteristics
Outcomes
Stimulation protocols
Synthesized data analyses
Overall summary effect



Study | Effect Size | 95% CI | Magnitude |
---|---|---|---|
Kumar et al 25 Yang et al 26 Shigematsu et al 27 Yuan et al 28 Ahn et al 29 Pingue et al 32 He et al 31 bHe et al 31 aWang et al Wang et al 33 Suntrup et al 34 Wang et al Chen et al Li et al Yang et al 39 bYang et al 39 aLiu et al Mao et al Pool | 0.86 −0.31 0.64 0.40 0.15 0.20 0.08 0.58 0.89 0.57 0.30 1.26 0.97 0.66 0.45 0.99 4.09 1.39 0.80 | −0.25 to 1.97 −1.31 to 0.68 −0.26 to 1.55 −0.32 to 1.12 −0.62 to 0.92 −0.42 to 0.82 −0.94 to 1.09 −0.47 to 1.62 0.04 to 1.73 −0.06 to 1.2 −0.21 to 0.81 0.44 to 2.09 0.52 to 1.42 0.07 to 1.25 −0.06 to 0.96 0.45 to 1.53 3.09 to 5.10 0.69 to 2.08 0.45 to 1.14 | Large Small Moderate Moderate Small Small Small Moderate Large Moderate Small Large Large Moderate Moderate Large Large Large |
Affected vs unaffected hemispheres
Patients with acute vs chronic stroke
Stimulation intensity
Stroke location
Safety and adverse events
Higgins JPT, Thomas J, Chandler J, et al, editors. Cochrane handbook for systematic reviews of interventions version 6.1 (updated September 2020). Available at: www.training.cochrane.org/handbook. Accessed April 15, 2021.
Study | Security |
---|---|
Kumar et al 25 | No adverse events. |
Yang et al 26 | The electrodes were placed in a slightly prickling position at the beginning of the stimulation. |
Shigematsu et al 27 | There was 1 case of abscission, which was not related to tDCS. |
Yuan et al 28 | No adverse events, good tolerance No adverse events, good tolerance. |
Ahn et al 29 | No adverse events, good tolerance. |
Pingue et al 32 | No adverse reactions. |
He et al 31 | Slight prickling occurred at the beginning of the stimulation. |
Wang et al 35 | Not described. |
Wang et al 33 | Not described. |
Suntrup et al 34 | No adverse events, good tolerance. |
Wang et al 35 | No adverse events, good tolerance. |
Chen et al 36 | Not described. |
Li et al 37 | Not described. |
Yang et al 39 | Not described. No serious complications, only a slight itching or ant walking sensation at the beginning of the stimulation. |
Liu et al 40 | No adverse events, good tolerance. |
Mao et al 38 | No adverse events, good tolerance. |
Discussion
Affected vs unaffected
Patients with acute vs chronic stroke
Stimulation intensity
Stroke location
Study limitations
Conclusions
Suppliers
- a.Review Manager; Cochrane Collaboration.
- b.EndNote X9; Thomson Reuters, Clarivate, Niles Software.
References
- The effect of pneumonia on mortality among patients hospitalized for acute stroke.Neurology. 2003; 60: 620-625
- Dysphagia in acute stroke: incidence, burden and impact on clinical outcome.PLoS One. 2016; 11e148424
- The effect of reclining position on swallowing function in stroke patients with dysphagia.J Oral Rehabil. 2020; 47: 1120-1128
- Transcranial direct current stimulation (tDCS): a promising treatment for major depressive disorder?.Brain Sci. 2018; 8: 81
- Transcranial direct current stimulation potentiates improvements in functional ability in patients with chronic stroke receiving constraint-induced movement therapy.Stroke. 2017; 48: 229-232
- Bihemispheric-tDCS and upper limb rehabilitation improves retention of motor function in chronic stroke: a pilot study.Front Hum Neurosci. 2016; 10: 258
- Time course of the induction of homeostatic plasticity generated by repeated transcranial direct current stimulation of the human motor cortex.J Neurophysiol. 2011; 105: 1141-1149
- Timing-dependent modulation of associative plasticity by general network excitability in the human motor cortex.J Neurosci. 2007; 27: 3807-3812
- How does transcranial DC stimulation of the primary motor cortex alter regional neuronal activity in the human brain?.Eur J Neurosci. 2005; 22: 495-504
- Transcranial direct current stimulation: state of the art 2008.Brain Stimul. 2008; 1: 206-223
- tDCS polarity effects in motor and cognitive domains: a meta-analytical review.Exp Brain Res. 2012; 216: 1-10
- Effects of transcranial electrical stimulation on cognition.Clin EEG Neurosci. 2012; 43: 192-199
- Speech facilitation by left inferior frontal cortex stimulation.Curr Biol. 2011; 21: 1403-1407
- Facilitation of probabilistic classification learning by transcranial direct current stimulation of the prefrontal cortex in the human.Neuropsychologia. 2004; 42: 113-117
- Improving working memory: the effect of combining cognitive activity and anodal transcranial direct current stimulation to the left dorsolateral prefrontal cortex.Brain Stimul. 2011; 4: 84-89
- Physiology of transcranial direct current stimulation.J ECT. 2018; 34: 144-152
- Effects of cortical anodal transcranial direct current stimulation on swallowing biomechanics.Neurogastroenterol Motil. 2018; 30: e13434
- Magnetoencephalographic evidence for the modulation of cortical swallowing processing by transcranial direct current stimulation.Neuroimage. 2013; 83: 346-354
- Catecholaminergic consolidation of motor cortical neuroplasticity in humans.Cereb Cortex. 2004; 14: 1240-1245
- tDCS-induced alterations in GABA concentration within primary motor cortex predict motor learning and motor memory: a 7 T magnetic resonance spectroscopy study.Neuroimage. 2014; 99: 237-243
- Anodal and cathodal tDCS modulate neural activity and selectively affect GABA and glutamate syntheses in the visual cortex of cats.J Physiol. 2020; 598: 3727-3745
- Direct current stimulation induces mGluR5-dependent neocortical plasticity.Ann Neurol. 2016; 80: 233-246
- Neurophysiological and behavioral effects of tDCS combined with constraint-induced movement therapy in poststroke patients.Neurorehabil Neural Repair. 2011; 25: 819-829
- Transcranial direct current stimulation reverses neurophysiological and behavioural effects of focal inhibition of human pharyngeal motor cortex on swallowing.J Physiol. 2014; 592: 695-709
- Noninvasive brain stimulation may improve stroke-related dysphagia: a pilot study.Stroke. 2011; 42: 1035-1040
- Effects of transcranial direct current stimulation (tDCS) on post-stroke dysphagia.Restor Neurol Neurosci. 2012; 30: 303-311
- Transcranial direct current stimulation improves swallowing function in stroke patients.Neurorehabil Neural Repair. 2013; 27: 363-369
- Effect of transcranial direct current stimulation on ataxic dysphagia after stroke.Chin J Rehabil Med. 2015; 30: 765-770
- Effect of bihemispheric anodal transcranial direct current stimulation for dysphagia in chronic stroke patients: a randomized clinical trial.J Rehabil Med. 2017; 49: 30-35
- Effect of transcranial direct current stimulation on dysphagia after cerebral apoplexy.Home Med. 2018; 9: 379-380
- Effect of transcranial direct current stimulation on dysphagia after stroke.Chin J Rehabil. 2018; 33: 45-47
- Dual transcranial direct current stimulation for poststroke dysphagia: a randomized controlled trial.Neurorehabil Neural Repair. 2018; 32: 635-644
- Clinical effect of transcranial direct current stimulation combined with swallowing training on swallowing dysfunction after cerebral apoplexy.Neural Inj Funct Reconstr. 2019; 14: 209-211
- Randomized trial of transcranial direct current stimulation for poststroke dysphagia.Ann Neurol. 2018; 83: 328-340
- Transcranial direct current stimulation improves the swallowing function in patients with cricopharyngeal muscle dysfunction following a brainstem stroke.Neurol Sci. 2020; 41: 569-574
- Effect analysis of transcranial direct current stimulation (tDCS) in the treatment of dysphagia in stroke patients.Chin Manipulation Rehabil Med. 2019; 10: 13-15
- Effect of transcranial direct current stimulation on dysphagia after brainstem stroke.Chin J Rehabil. 2020; 35: 625-628
- Clinical study on swallowing function of brainstem stroke by tDCS.Neurol Sci. 2021; 11: 1-8
- Effect of transcranial direct current stimulation on dysphagia of true pseudobulbar paralysis after cerebral apoplexy.Chin J Phys Med Rehabil. 2020; 42: 199-200
- Analysis of clinical treatment effect of dysphagia after stroke.China Health Stand Manage. 2020; 11: 49-51
- Reliability of the PEDro Scale for rating quality of randomized controlled trials.Phys Ther. 2003; 83: 713-721
- Evidence for physiotherapy practice: a survey of the Physiotherapy Evidence Database (PEDro).Aust J Physiother. 2002; 48: 43-49
- Stroke rehabilitation evidence-based review: methodology.Top Stroke Rehabil. 2003; 10: 1-7
The Cochrane Collaboration. Review Manager. Available at: https://training.cochrane.org. Accessed September 21, 2020.
- Optimally estimating the sample mean from the sample size, median, mid-range, and/or mid-quartile range.Stat Methods Med Res. 2018; 27: 1785-1805
- Estimating the sample mean and standard deviation from the sample size, median, range and/or interquartile range.BMC Med Res Methodol. 2014; 14: 135
- Statistical power analysis for the behavioral sciences.Academic Press, London2013
Higgins JPT, Thomas J, Chandler J, et al, editors. Cochrane handbook for systematic reviews of interventions version 6.1 (updated September 2020). Available at: www.training.cochrane.org/handbook. Accessed April 15, 2021.
- Statistical models and methods for network meta-analysis.Phytopathology. 2016; 106: 792-806
- A method of moments estimator for random effect multivariate meta-analysis.Biometrics. 2012; 68: 1278-1284
- Measuring inconsistency in meta-analyses.BMJ. 2013; 327: 557-560
Thomson ResearchSoft. Endnote. Available at: https://endnote.com. Accessed April 15, 2021.
- Bias in meta-analysis detected by a simple, graphical test.BMJ. 1997; 315: 629-634
- The Dysphagia Outcome and Severity Scale.Dysphagia. 1999; 14: 139-145
- Analysis of a physician tool for evaluating dysphagia on an inpatient stroke unit: the modified Mann Assessment of Swallowing Ability.J Stroke Cerebrovasc Dis. 2010; 19: 49-57
- Quantifying swallowing function after stroke: a functional dysphagia scale based on videofluoroscopic studies.Arch Phys Med Rehabil. 2001; 82: 677-682
- Initial psychometric assessment of a functional oral intake scale for dysphagia in stroke patients.Arch Phys Med Rehabil. 2005; 86: 1516-1520
- Structured reports of videofluoroscopic swallowing studies have the potential to improve overall report quality compared to free text reports.Eur Radiol. 2018; 28: 308-315
- Transcranial direct current stimulation for post-stroke dysphagia: a systematic review and meta-analysis of randomized controlled trials.J Neurol. 2021; 268: 293-304
- Effects of non-invasive brain stimulation on post-stroke dysphagia: a systematic review and meta-analysis of randomized controlled trials.Clin Neurophysiol. 2016; 127: 956-968
- Effectiveness of non-invasive brain stimulation in dysphagia subsequent to stroke: a systemic review and meta-analysis.Dysphagia. 2015; 30: 383-391
- Comparative efficacy of non-invasive neurostimulation therapies for poststroke dysphagia: a systematic review and meta-analysis.Clin Neurophysiol. 2021; 51: 493-506
- Effects of neurostimulation on poststroke dysphagia: a synthesis of current evidence from randomized controlled trials.Neuromodulation. 2021; 24: 1388-1401
- Motor cortex activation is preserved in patients with chronic hemiplegic stroke.Ann Neurol. 2002; 52: 607-616
- The cortical topography of human swallowing musculature in health and disease.Nat Med. 1996; 2: 1217-1224
- Treatment of post-stroke dysphagia with repetitive transcranial magnetic stimulation.Acta Neurol Scand. 2009; 119: 155-161
- Recovery of swallowing after dysphagic stroke relates to functional reorganization in the intact motor cortex.Gastroenterology. 1998; 115: 1104-1112
Hamdy S, Rothwell JC, Aziz Q, Thompson DG. Organization and reorganization of human swallowing motor cortex: implications for recovery after stroke. Clin Sci (Lond) 200;99:151-157.
- Effects of combined peripheral nerve stimulation and brain polarization on performance of a motor sequence task after chronic stroke.Stroke. 2009; 40: 1764-1771
- Targeting unlesioned pharyngeal motor cortex improves swallowing in healthy individuals and after dysphagic stroke.Gastroenterology. 2012; 142: 29-38
- European Stroke Organization and European Society for Swallowing Disorders guideline for the diagnosis and treatment of post-stroke dysphagia.Eur Stroke J. 2021; 6: LXXXIX-LXXCXV
Article info
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Footnotes
Supported by the Science and Technology Project of Health Commission of Jiangxi Province (202130250), and the Key Research and Developement Plan of Jiangxi Province (20203BBGL73125; 20192BBG70016).
Ethical Standard Statement: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Disclosures: none.
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