Investigating the feasibility of cerebellar transcranial direct current stimulation to facilitate post-stroke overground gait performance in chronic stroke: a partial least-squares regression approach

Abstract Background Investigation of lobule-specific electric field effects of cerebellar transcranial direct current stimulation (ctDCS) on overground gait performance has not been performed, so this study aimed to investigate the feasibility of two lobule-specific bilateral ctDCS montages to facilitate overground walking in chronic stroke. Methods Ten chronic post-stroke male subjects participated in this repeated-measure single-blind crossover study, where we evaluated the single-session effects of two bilateral ctDCS montages that applied 2 mA via 3.14 cm2 disc electrodes for 15 min targeting (a) dentate nuclei (also, anterior and posterior lobes), and (b) lower-limb representations (lobules VIIb-IX). A two-sided Wilcoxon rank-sum test was performed at a 5% significance level on the percent normalized change measures in the overground gait performance. Partial least squares regression (PLSR) analysis was performed on the quantitative gait parameters as response variables to the mean lobular electric field strength as the predictors. Clinical assessments were performed with the Ten-Meter walk test (TMWT), Timed Up & Go (TUG), and the Berg Balance Scale based on minimal clinically important differences (MCID). Results The ctDCS montage specific effect was found significant using a two-sided Wilcoxon rank-sum test at a 5% significance level for 'Step Time Affected Leg' (p = 0.0257) and '%Stance Time Unaffected Leg' (p = 0.0376). The changes in the quantitative gait parameters were found to be correlated to the mean electric field strength in the lobules based on PLSR analysis (R2 statistic = 0.6574). Here, the mean electric field strength at the cerebellar lobules, Vermis VIIIb, Ipsi-lesional IX, Vermis IX, Ipsi-lesional X, had the most loading and were positively related to the 'Step Time Affected Leg' and '%Stance Time Unaffected Leg,' and negatively related to the '%Swing Time Unaffected Leg,' '%Single Support Time Affected Leg.' Clinical assessments found similar improvement in the TMWT (MCID: 0.10 m/s), TUG (MCID: 8 s), and BBS score (MCID: 12.5 points) for both the ctDCS montages. Conclusion Our feasibility study found an association between the lobular mean electric field strength and the changes in the quantitative gait parameters following a single ctDCS session in chronic stroke. Both the ctDCS montages improved the clinical outcome measures that should be investigated with a larger sample size for clinical validation. Trial registration: Being retrospectively registered.

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Investigating the Feasibility of Cerebellar Transcranial Direct Current Stimulation to facilitate Post-Stroke Overground Gait Performance in Chronic Stroke: a partial least-squares regression approach

10.21203/rs.3.rs-39560/v3 ◽

2020 ◽

Author(s):

Dhaval Solanki ◽

Zeynab Rezaee ◽

Anirban Dutta ◽

Uttama Lahiri

Keyword(s):

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Chronic Stroke ◽

Least Squares Regression ◽

Significance Level ◽

Gait Performance ◽

Wilcoxon Rank Sum Test ◽

Gait Parameters ◽

The Mean

Abstract Background: Investigation of lobule-specific electric field effects of cerebellar transcranial direct current stimulation (ctDCS) on overground gait performance has not been performed, so this study aimed to investigate the feasibility of two lobule-specific bilateral ctDCS montages to facilitate overground walking in chronic stroke. Methods: Ten chronic post-stroke male subjects participated in this repeated-measure single-blind crossover study, where we evaluated the single-session effects of two bilateral ctDCS montages that applied 2mA via 3.14cm2 disc electrodes for 15 minutes targeting a) dentate nuclei (also, anterior and posterior lobes), and b) lower-limb representations (lobules VIIb-IX). A two-sided Wilcoxon rank-sum test was performed at a 5% significance level on the percent normalized change measures in the overground gait performance. Partial least squares regression (PLSR) analysis was performed on the quantitative gait parameters as response variables to the mean lobular electric field strength as the predictors. Clinical assessments were performed with the Ten-Meter walk test (TMWT), Timed Up & Go (TUG), and the Berg Balance Scale based on minimal clinically important differences (MCID).Results: The ctDCS montage specific effect was found significant using a two-sided Wilcoxon rank-sum test at a 5% significance level for 'Step Time Affected Leg' (p=0.0257) and '%Stance Time Unaffected Leg' (p=0.0376). The changes in the quantitative gait parameters were found to be correlated to the mean electric field strength in the lobules based on PLSR analysis (R2 statistic = 0.6574). Here, the mean electric field strength at the cerebellar lobules, Vermis VIIIb, Ipsi-lesional IX, Vermis IX, Ipsi-lesional X, had the most loading and were positively related to the 'Step Time Affected Leg' and '%Stance Time Unaffected Leg,' and negatively related to the '%Swing Time Unaffected Leg,' '%Single Support Time Affected Leg.' Clinical assessments found similar improvement in the TMWT (MCID: 0.10m/sec), TUG (MCID: 8sec), and BBS score (MCID: 12.5 points) for both the ctDCS montages. Conclusion: Our feasibility study found an association between the lobular mean electric field strength and the changes in the quantitative gait parameters following a single ctDCS session in chronic stroke. Both the ctDCS montages improved the clinical outcome measures that should be investigated with a larger sample size for clinical validation.

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Investigating the Feasibility of Cerebellar Transcranial Direct Current Stimulation to facilitate Post-Stroke Overground Gait Performance in Chronic Stroke: a partial least-squares regression approach

10.21203/rs.3.rs-39560/v2 ◽

2020 ◽

Author(s):

Dhaval Solanki ◽

Zeynab Rezaee ◽

Anirban Dutta ◽

Uttama Lahiri

Keyword(s):

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Least Squares Regression ◽

Significance Level ◽

Gait Performance ◽

Post Stroke ◽

Wilcoxon Rank Sum Test ◽

Gait Parameters ◽

The Mean

Abstract Background: Cerebellar transcranial Direct Current Stimulation (ctDCS) has been shown to be promising as an adjuvant treatment to facilitate post-stroke gait rehabilitation; however, investigation of lobule-specific electric field effects on overground gait performance has not been performed. Methods: Ten chronic post-stroke male subjects participated in this repeated-measure single-blind crossover study, where we evaluated the single-session effects of two bilateral ctDCS montages that applied 2mA via 3.14cm 2 disc electrodes for 15 minutes targeting a) dentate nuclei (also, anterior and posterior lobes), and b) lower-limb representations (lobules VIIb-IX). A two-sided Wilcoxon rank-sum test was performed at 5% significance level on the percent normalized change measures in the overground gait performance. Partial least squares regression (PLSR) analysis was performed on the quantitative gait parameters as response variables to the mean lobular electric field strength as the predictors. Clinical assessments were performed with the Ten-Meter walk test (TMWT), Timed Up & Go (TUG), and the Berg Balance Scale based on minimal clinically important differences (MCID). Results: The ctDCS montage specific effect was found significant using a two-sided Wilcoxon rank-sum test at a 5% significance level for 'Step Time Affected Leg' (p=0.0257) and '%Stance Time Unaffected Leg' (p=0.0376). The changes in the quantitative gait parameters were found to be correlated to the mean electric field strength in the lobules based on PLSR analysis ( R 2 statistic = 0.6574). Here, the mean electric field strength at the cerebellar lobules, Vermis VIIIb, Ipsi-lesional IX, Vermis IX, Ipsi-lesional X, had the most loading, and were positively related to the 'Step Time Affected Leg' and '%Stance Time Unaffected Leg,' and negatively related to the '%Swing Time Unaffected Leg,' '%Single Support Time Affected Leg.' Clinical assessments found similar improvement in the TMWT (MCID: 0.10m/sec), TUG (MCID: 8sec), and BBS score (MCID: 12.5 points) for both the ctDCS montages. Conclusion: Our feasibility study found an association between the lobular mean electric field strength and the changes in the quantitative gait parameters following a single ctDCS session in chronic stroke. Both the ctDCS montages improved the clinical outcome measures that should be investigated with a larger sample size for clinical validation.

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Investigating the Effects of Cerebellar Transcranial Direct Current Stimulation on Post-Stroke Overground Gait Performance: A Partial Least-Squares Regression Approach

10.20944/preprints202006.0338.v1 ◽

2020 ◽

Author(s):

Dhaval Solanki ◽

Zeynab Rezaee ◽

Anirban Dutta ◽

Uttama Lahiri

Keyword(s):

Field Strength ◽

Electric Field ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Partial Least Squares Regression ◽

Least Squares Regression ◽

Significance Level ◽

Gait Performance ◽

Post Stroke ◽

The Mean

Stroke often results in impaired gait, which can limit community ambulation and the quality of life. Recent works have shown the feasibility of transcranial Direct Current Stimulation (tDCS) as an adjuvant treatment to facilitate gait rehabilitation. Since the cerebellum plays an essential role in balance and movement coordination, which is crucial for independent overground ambulation, so, we investigated the effects of cerebellar tDCS (ctDCS) on the post-stroke overground gait performance in chronic stroke survivors. Fourteen chronic post-stroke male subjects were recruited based on convenience sampling at the collaborating hospitals where ten subjects finally participated in the ctDCS study. We evaluated the effects of two ctDCS montages with 2mA direct current, a) optimized configuration for dentate stimulation with 3.14cm2 disc anode at PO10h (10/5 EEG system) and 3.14cm2 disc cathode at PO9h (10/5 EEG system), and b) optimized configuration for leg lobules VII-IX stimulation with 3.14cm2 disc anode at Exx8 (electrodes defined by ROAST) and 3.14cm2 disc cathode at Exx7. We found ctDCS to be acceptable by all the exposed subjects. The ctDCS intervention had an effect on the 'Normalised Step length Affected side' (p=0.1) and 'Gait Stability Ratio' (p=0.0569), which was found using Wilcoxon signed-rank test at 10% significance level. Also, ctDCS montage specific effect was found using a two-sided Wilcoxon rank-sum test at a 5% significance level for 'Step Time Affected Leg' (p=0.0257) and '%Stance Time Unaffected Leg' (p=0.0376). Moreover, the changes in the quantitative gait parameters across both the montages were found to be correlated to the mean electric field strength in the lobules based on partial least squares regression analysis (R2 statistic = 0.6574) where the mean electric field strength at the cerebellar lobules, Vermis VIIIb, Ipsilesional IX, Vermis IX, Ipsilesional X, had the most loading. In conclusion, our feasibility study indicated the potential of a single session of ctDCS to contribute to the immediate improvement in the balance and gait performance in terms of gait-related indices and clinical gait measures.

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Investigating the Effects of Cerebellar Transcranial Direct Current Stimulation on Post-Stroke Overground Gait Performance: a partial least-squares regression approach

10.21203/rs.3.rs-39560/v1 ◽

2020 ◽

Author(s):

Dhaval Solanki ◽

Zeynab Rezaee ◽

Anirban Dutta ◽

Uttama Lahiri

Keyword(s):

Field Strength ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Partial Least Squares Regression ◽

Least Squares Regression ◽

Significance Level ◽

Gait Performance ◽

Post Stroke ◽

Wilcoxon Rank Sum Test ◽

The Mean

Abstract Background Stroke often results in impaired gait, which can limit community ambulation and the quality of life. Recent works have shown the feasibility of transcranial Direct Current Stimulation (tDCS) as an adjuvant treatment to facilitate gait rehabilitation. Since the cerebellum plays an essential role in balance and movement coordination, which is crucial for independent overground ambulation, so, we investigated the effects of cerebellar tDCS (ctDCS) on the post-stroke overground gait performance in chronic stroke survivors. Methods Fourteen chronic post-stroke male subjects were recruited based on convenience sampling at the collaborating hospitals where ten subjects finally participated in the ctDCS gait study. We evaluated the effects of two ctDCS montages with 2 mA direct current, a) optimized configuration for dentate stimulation with 3.14 cm2 disc anode at PO10h (10/5 EEG system) and 3.14 cm2 disc cathode at PO9h (10/5 EEG system), and b) optimized configuration for leg lobules VII-IX stimulation with 3.14 cm2 disc anode at Exx8 (electrodes defined by ROAST) and 3.14 cm2 disc cathode at Exx7. Two-sided Wilcoxon rank-sum test was performed at the 5% significance level on the percent normalized change measures in the overground gait performance. Results We found ctDCS to be acceptable by all the exposed subjects. The ctDCS intervention had an effect on the 'Normalised Step length Affected side' (p = 0.1) and 'Gait Stability Ratio' (p = 0.0569), which was found using Wilcoxon signed-rank test at 10% significance level. Also, ctDCS montage specific effect was found using a two-sided Wilcoxon rank-sum test at a 5% significance level for 'Step Time Affected Leg' (p = 0.0257) and '%Stance Time Unaffected Leg' (p = 0.0376). Moreover, the changes in the quantitative gait parameters across both the montages were found to be correlated to the mean electric field strength in the lobules based on partial least squares regression analysis (R2 statistic = 0.6574) where the mean electric field strength at the cerebellar lobules, Vermis VIIIb, Ipsilesional IX, Vermis IX, Ipsilesional X, had the most loading. Conclusion Our feasibility study indicated the potential of a single session of ctDCS to contribute to the immediate improvement in the balance and gait performance in terms of gait-related indices and clinical gait measures.

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Optical Measurement of the Electric Field Strength in a Gel Insulator

IEEJ Transactions on Electronics Information and Systems ◽

10.1541/ieejeiss.136.1420 ◽

2016 ◽

Vol 136 (10) ◽

pp. 1420-1421

Author(s):

Yusuke Tanaka ◽

Yuji Nagaoka ◽

Hyeon-Gu Jeon ◽

Masaharu Fujii ◽

Haruo Ihori

Keyword(s):

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Optical Measurement

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Effect of external magnetic field on lane formation in driven pair-ion plasmas

Journal of Plasma Physics ◽

10.1017/s0022377821000027 ◽

2021 ◽

Vol 87 (2) ◽

Author(s):

Swati Baruah ◽

U. Sarma ◽

R. Ganesh

Keyword(s):

Magnetic Field ◽

External Magnetic Field ◽

Field Strength ◽

Electric Field ◽

Electric Field Strength ◽

Coupling Parameter ◽

Critical Parameters ◽

Coulomb Coupling ◽

Lane Formation ◽

Parameter Values

Lane formation dynamics in externally driven pair-ion plasma (PIP) particles is studied in the presence of external magnetic field using Langevin dynamics (LD) simulation. The phase diagram obtained distinguishing the no-lane and lane states is systematically determined from a study of various Coulomb coupling parameter values. A peculiar lane formation-disintegration parameter space is identified; lane formation area extended to a wide range of Coulomb coupling parameter values is observed before disappearing to a mixed phase. The different phases are identified by calculating the order parameter. This and the critical parameters are calculated directly from LD simulation. The critical electric field strength value above which the lanes are formed distinctly is obtained, and it is observed that in the presence of the external magnetic field, the PIP system requires a higher value of the electric field strength to enter into the lane formation state than that in the absence of the magnetic field. We further find out the critical value of electric field frequency beyond which the system exhibits a transition back to the disordered state and this critical frequency is found as an increasing function of the electric field strength in the presence of an external magnetic field. The movement of the lanes is also observed in a direction perpendicular to that of the applied electric and magnetic field directions, which reveals the existence of the electric field drift in the system under study. We also use an oblique force field as the external driving force, both in the presence and absence of the external magnetic field. The application of this oblique force changes the orientation of the lane structures for different applied oblique angle values.

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