Addressing the inconsistent electric fields of tDCS by using patient-tailored configurations in chronic stroke: Implications for treatment

Cruijsen, Joris van der; Dooren, Renée F.; Schouten, Alfred C.; Oostendorp, Thom F.; Frens, Maarten A.; Ribbers, Gerard M.; Helm, F.C.T. van der; Kwakkel, Gert; Selles, Ruud W.

doi:10.1016/j.nicl.2022.103178

Cited by 10 publications

(19 citation statements)

References 66 publications

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“…Few prior studies have investigated the use of the more focal HD-TDCS with a 1 + 4 electrode montage in stroke patients with aphasia [37,77] and motor function in chronic stroke [78,79]. Prior studies have used field modeling to simulate the optimal TDCS electrode placement but in chronic stroke patients [27,80] and these studies did not individualize the current intensity of the stimulation. The largest recovery occurs within the first 12 months post-stroke.…”

Section: Discussionmentioning

confidence: 99%

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Patient-tailored transcranial direct current stimulation to improve stroke rehabilitation: study protocol of a randomized sham-controlled trial

Kolmos

Madsen

Liu

et al. 2023

Trials

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Background Many patients do not fully regain motor function after ischemic stroke. Transcranial direct current stimulation (TDCS) targeting the motor cortex may improve motor outcome as an add-on intervention to physical rehabilitation. However, beneficial effects on motor function vary largely among patients within and across TDCS trials. In addition to a large heterogeneity of study designs, this variability may be caused by the fact that TDCS was given as a one-size-fits-all protocol without accounting for anatomical differences between subjects. The efficacy and consistency of TDCS might be improved by a patient-tailored design that ensures precise targeting of a physiologically relevant area with an appropriate current strength. Methods In a randomized, double-blinded, sham-controlled trial, patients with subacute ischemic stroke and residual upper-extremity paresis will receive two times 20 min of focal TDCS of ipsilesional primary motor hand area (M1-HAND) during supervised rehabilitation training three times weekly for 4 weeks. Anticipated 60 patients will be randomly assigned to active or sham TDCS of ipsilesional M1-HAND, using a central anode and four equidistant cathodes. The placement of the electrode grid on the scalp and current strength at each cathode will be personalized based on individual electrical field models to induce an electrical current of 0.2 V/m in the cortical target region resulting in current strengths between 1 and 4 mA. Primary endpoint will be the difference in change of Fugl-Meyer Assessment of Upper Extremity (FMA-UE) score between active TDCS and sham at the end of the intervention. Exploratory endpoints will include UE-FMA at 12 weeks. Effects of TDCS on motor network connectivity and interhemispheric inhibition will be assessed with functional MRI and transcranial magnetic stimulation. Discussion The study will show the feasibility and test the efficacy of personalized, multi-electrode anodal TDCS of M1-HAND in patients with subacute stroke patients with upper-extremity paresis. Concurrent multimodal brain mapping will shed light into the mechanisms of action of therapeutic personalized TDCS of M1-HAND. Together, the results from this trial may inform future personalized TDCS studies in patients with focal neurological deficits after stroke.

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Section: Discussionmentioning

confidence: 99%

Section: Background and Rationalementioning

confidence: 99%

Patient-tailored transcranial direct current stimulation to improve stroke rehabilitation: study protocol of a randomized sham-controlled trial

Kolmos

Madsen

Liu

et al. 2023

Trials

View full text Add to dashboard Cite

show abstract

“…Few prior studies have investigated the use of the more focal HD-TDCS with a 1+4 electrode montage in stroke patients with aphasia 75,76 and motor function in chronic stroke 77,78 . Prior studies have used field modelling to simulate the optimal TDCS electrode placement but in chronic stroke patients 27,79 and these studies did not individualize current intensity of the stimulation. The largest recovery occurs within the first 12 months post-stroke.…”

Section: Discussionmentioning

confidence: 99%

“…Using individual magnetic resonance imaging (MRI) scans, electric field modeling enables a precise estimation of the electric field distribution in the brain during transcranial electrical brain stimulation and an optimization of electrode placement and dosing of interventional TDCS [24][25][26][27] Patients with post-stroke upper extremity disability show an impaired motor network structure including a reduced excitatory influence from pre-motor brain areas and disinhibition of the contralesional M1-HAND 28,29 . The interhemispheric imbalance between precentral motor cortices tends to improve with motor recovery and is often completely restored in patients with full recovery [28][29][30] .…”

Section: Introduction Background and Rationalementioning

confidence: 99%

Patient-tailored Transcranial Direct Current Stimulation to Improve Stroke Rehabilitation: Study Protocol of a Randomized Sham-controlled Trial

Kolmos

Madsen²,

Liu³

et al. 2023

Preprint

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Background: Many patients do not fully regain motor function after ischemic stroke. Transcranial Direct Current Stimulation (TDCS) targeting the motor cortex may improve motor outcome as an add-on intervention to physical rehabilitation. However, beneficial effects on motor function varies largely among patients within and across TDCS trials. In addition to a large heterogeneity of study designs, this variability may be caused by the fact that TDCS was given as a one-size-fits-all protocol without accounting for anatomical differences between subjects. The efficacy and consistency of TDCS might be improved by a patient-tailored design that ensures precise targeting of a physiological relevant area with an appropriate current strength. Methods: In a randomized, double-blinded, sham-controlled trial, patients with subacute ischemic stroke and residual upper-extremity paresis will receive two times 20 minutes of focal TDCS of ipsi-lesional primary motor hand area (M1-HAND) during supervised rehabilitation training three times weekly for four weeks. Anticipated 60 patients will be randomly assigned to active or sham TDCS of ipsi-lesional M1-HAND, using a central anode and four equidistant cathodes. The placement of the electrode grid on the scalp and current strength at each cathode will be personalized based on individual electrical field models to induce an electrical current of 0.2 V/m in the cortical target region resulting in current strengths between 1-4 mA. Primary endpoint will be difference in change of Fugl-Meyer Assessment of Upper Extremity (FMA-UE) score between active TDCS and sham at the end of the intervention. Exploratory endpoints will include UE-FMA at 12 weeks. Effects of TDCS on motor network connectivity and interhemispheric inhibition will be assessed with functional MRI and transcranial magnetic stimulation. Discussion: The study will show the feasibility and test the efficacy of personalized, multi-electrode anodal TDCS of M1-HAND in patients with subacute stroke patients with upper-extremity paresis. Concurrent multimodal brain mapping will shed light into the mechanisms of action of therapeutic personalized TDCS of M1-HAND. Together, the results from this trial may inform future personalized TDCS studies in patients with focal neurological deficits after stroke.

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“…Computational modeling has been used to optimize tDCS for stroke patients by adjusting the electrode positions, to maximize the electric eld intensities in target areas [9,15,16]. One small pilot study showed that optimized tDCS increased the electric eld in the target area by 63% compared to that of conventional approaches [16].…”

Section: Introductionmentioning

confidence: 99%

Electric Field Simulation and Appropriate Electrode Positioning for Optimized Transcranial Direct Current Stimulation of Stroke Patients: An In Silico Model

Yoon,

Park,

Yoo

et al. 2023

Preprint

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Transcranial Direct Current Stimulation (tDCS) has benefits for motor rehabilitation in stroke patients, but its clinical application is limited due to inter-individual heterogeneous effects. Recently, optimized tDCS that considers individual brain structure has been proposed, but the utility thereof has not been studied in detail. We explored whether optimized tDCS provides unique electrode positions for each patient and creates a higher target electric field than the conventional approach. A comparative within-subject simulation study was conducted using data collected for a randomized controlled study evaluating the effect of optimized tDCS on upper extremity function in stroke patients. Using Neurophet tES LAB 3.0 software, individual brain models were created based on magnetic resonance images and tDCS simulations were performed for each of the conventional and optimized configurations. A comparison of electrode positions between conventional tDCS and optimized tDCS was quantified by calculation of Euclidean distances. A total of 21 stroke patients were studied. Optimized tDCS produced a higher electric field in the hand motor region than conventional tDCS, with an average improvement of 20%. The electrode montage for optimized tDCS was unique to each patient and exhibited various configurations that differed from electrode placement of conventional tDCS. Optimized tDCS afforded a higher electric field in the target of a stroke patient compared to conventional tDCS, which was made possible by appropriately positioning the electrodes. Our findings may encourage further trials on optimized tDCS for motor rehabilitation after stroke.

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Addressing the inconsistent electric fields of tDCS by using patient-tailored configurations in chronic stroke: Implications for treatment

Cited by 10 publications

References 66 publications

Patient-tailored transcranial direct current stimulation to improve stroke rehabilitation: study protocol of a randomized sham-controlled trial

Patient-tailored transcranial direct current stimulation to improve stroke rehabilitation: study protocol of a randomized sham-controlled trial

Patient-tailored Transcranial Direct Current Stimulation to Improve Stroke Rehabilitation: Study Protocol of a Randomized Sham-controlled Trial

Electric Field Simulation and Appropriate Electrode Positioning for Optimized Transcranial Direct Current Stimulation of Stroke Patients: An In Silico Model

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