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Transcranial Direct Current Stimulation Over the Primary and Secondary Somatosensory Cortices Transiently Improves Tactile Spatial Discrimination in Stroke Patients.

Fujimoto S, Kon N, Otaka Y, Yamaguchi T, Nakayama T, Kondo K, Ragert P, Tanaka S - Front Neurosci (2016)

Bottom Line: We found that GOT thresholds for the affected index finger during and 10 min after the S1 and S2 conditions were significantly lower compared with each sham condition.GOT thresholds were not significantly different between the S1 and S2 conditions at any time point.We concluded that dual-hemisphere tDCS over S1 and S2 can transiently enhance tactile discriminative task performance in chronic stroke patients with sensory dysfunction.

View Article: PubMed Central - PubMed

Affiliation: Tokyo Bay Rehabilitation HospitalChiba, Japan; Laboratory of Psychology, Hamamatsu University School of MedicineShizuoka, Japan; Department of Public Health, Kyoto University Graduate School of MedicineKyoto, Japan; Medley, Inc.Tokyo, Japan.

ABSTRACT
In healthy subjects, dual hemisphere transcranial direct current stimulation (tDCS) over the primary (S1) and secondary somatosensory cortices (S2) has been found to transiently enhance tactile performance. However, the effect of dual hemisphere tDCS on tactile performance in stroke patients with sensory deficits remains unknown. The purpose of this study was to investigate whether dual hemisphere tDCS over S1 and S2 could enhance tactile discrimination in stroke patients. We employed a double-blind, crossover, sham-controlled experimental design. Eight chronic stroke patients with sensory deficits participated in this study. We used a grating orientation task (GOT) to measure the tactile discriminative threshold of the affected and non-affected index fingers before, during, and 10 min after four tDCS conditions. For both the S1 and S2 conditions, we placed an anodal electrode over the lesioned hemisphere and a cathodal electrode over the opposite hemisphere. We applied tDCS at an intensity of 2 mA for 15 min in both S1 and S2 conditions. We included two sham conditions in which the positions of the electrodes and the current intensity were identical to that in the S1 and S2 conditions except that current was delivered for the initial 15 s only. We found that GOT thresholds for the affected index finger during and 10 min after the S1 and S2 conditions were significantly lower compared with each sham condition. GOT thresholds were not significantly different between the S1 and S2 conditions at any time point. We concluded that dual-hemisphere tDCS over S1 and S2 can transiently enhance tactile discriminative task performance in chronic stroke patients with sensory dysfunction.

No MeSH data available.


Related in: MedlinePlus

Results of grating orientation task in dual-hemisphere S1 and S2 tDCS. The mean threshold is plotted as a time course relative to the intervention, with bars indicating standard deviation (SD). (A) Indicates the effect of the stimulation on the affected index finger when adopting tDCS over S1. (B) Indicates the effect of the stimulation on the non-affected index finger when adopting tDCS over S1. (C) Indicates the effect of the stimulation over the affected index finger when adopting tDCS over S2. (D) Indicates the effect of the stimulation on the non-affected index finger when adopting tDCS over S2. Compared with sham tDCS (white circle, p < 0.05), dual-hemisphere tDCS (black circle) significantly improved the grating orientation threshold for the affected index finger during and 10 min after the stimulation over both S1 and S2. However, we found no significant effects of tDCS on the non-affected index finger, regardless of stimulation site.
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Figure 2: Results of grating orientation task in dual-hemisphere S1 and S2 tDCS. The mean threshold is plotted as a time course relative to the intervention, with bars indicating standard deviation (SD). (A) Indicates the effect of the stimulation on the affected index finger when adopting tDCS over S1. (B) Indicates the effect of the stimulation on the non-affected index finger when adopting tDCS over S1. (C) Indicates the effect of the stimulation over the affected index finger when adopting tDCS over S2. (D) Indicates the effect of the stimulation on the non-affected index finger when adopting tDCS over S2. Compared with sham tDCS (white circle, p < 0.05), dual-hemisphere tDCS (black circle) significantly improved the grating orientation threshold for the affected index finger during and 10 min after the stimulation over both S1 and S2. However, we found no significant effects of tDCS on the non-affected index finger, regardless of stimulation site.

Mentions: In the paretic hand, the two-way repeated measures ANOVA revealed significant main effects of INTERVENTION [F(1, 7) = 15.89, p < 0.01], TIME [F(2, 14) = 13.17, p < 0.01], and their interaction [F(2, 14) = 14.90, p < 0.01; Figure 2A]. A post-hoc analysis revealed that the GOT threshold during tDCS over S1 was significantly lower than that in the sham condition (p < 0.01). Additionally, 10 min after tDCS over S1, the GOT threshold was still significantly lower than that after the sham stimulation (p < 0.01).


Transcranial Direct Current Stimulation Over the Primary and Secondary Somatosensory Cortices Transiently Improves Tactile Spatial Discrimination in Stroke Patients.

Fujimoto S, Kon N, Otaka Y, Yamaguchi T, Nakayama T, Kondo K, Ragert P, Tanaka S - Front Neurosci (2016)

Results of grating orientation task in dual-hemisphere S1 and S2 tDCS. The mean threshold is plotted as a time course relative to the intervention, with bars indicating standard deviation (SD). (A) Indicates the effect of the stimulation on the affected index finger when adopting tDCS over S1. (B) Indicates the effect of the stimulation on the non-affected index finger when adopting tDCS over S1. (C) Indicates the effect of the stimulation over the affected index finger when adopting tDCS over S2. (D) Indicates the effect of the stimulation on the non-affected index finger when adopting tDCS over S2. Compared with sham tDCS (white circle, p < 0.05), dual-hemisphere tDCS (black circle) significantly improved the grating orientation threshold for the affected index finger during and 10 min after the stimulation over both S1 and S2. However, we found no significant effects of tDCS on the non-affected index finger, regardless of stimulation site.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4814559&req=5

Figure 2: Results of grating orientation task in dual-hemisphere S1 and S2 tDCS. The mean threshold is plotted as a time course relative to the intervention, with bars indicating standard deviation (SD). (A) Indicates the effect of the stimulation on the affected index finger when adopting tDCS over S1. (B) Indicates the effect of the stimulation on the non-affected index finger when adopting tDCS over S1. (C) Indicates the effect of the stimulation over the affected index finger when adopting tDCS over S2. (D) Indicates the effect of the stimulation on the non-affected index finger when adopting tDCS over S2. Compared with sham tDCS (white circle, p < 0.05), dual-hemisphere tDCS (black circle) significantly improved the grating orientation threshold for the affected index finger during and 10 min after the stimulation over both S1 and S2. However, we found no significant effects of tDCS on the non-affected index finger, regardless of stimulation site.
Mentions: In the paretic hand, the two-way repeated measures ANOVA revealed significant main effects of INTERVENTION [F(1, 7) = 15.89, p < 0.01], TIME [F(2, 14) = 13.17, p < 0.01], and their interaction [F(2, 14) = 14.90, p < 0.01; Figure 2A]. A post-hoc analysis revealed that the GOT threshold during tDCS over S1 was significantly lower than that in the sham condition (p < 0.01). Additionally, 10 min after tDCS over S1, the GOT threshold was still significantly lower than that after the sham stimulation (p < 0.01).

Bottom Line: We found that GOT thresholds for the affected index finger during and 10 min after the S1 and S2 conditions were significantly lower compared with each sham condition.GOT thresholds were not significantly different between the S1 and S2 conditions at any time point.We concluded that dual-hemisphere tDCS over S1 and S2 can transiently enhance tactile discriminative task performance in chronic stroke patients with sensory dysfunction.

View Article: PubMed Central - PubMed

Affiliation: Tokyo Bay Rehabilitation HospitalChiba, Japan; Laboratory of Psychology, Hamamatsu University School of MedicineShizuoka, Japan; Department of Public Health, Kyoto University Graduate School of MedicineKyoto, Japan; Medley, Inc.Tokyo, Japan.

ABSTRACT
In healthy subjects, dual hemisphere transcranial direct current stimulation (tDCS) over the primary (S1) and secondary somatosensory cortices (S2) has been found to transiently enhance tactile performance. However, the effect of dual hemisphere tDCS on tactile performance in stroke patients with sensory deficits remains unknown. The purpose of this study was to investigate whether dual hemisphere tDCS over S1 and S2 could enhance tactile discrimination in stroke patients. We employed a double-blind, crossover, sham-controlled experimental design. Eight chronic stroke patients with sensory deficits participated in this study. We used a grating orientation task (GOT) to measure the tactile discriminative threshold of the affected and non-affected index fingers before, during, and 10 min after four tDCS conditions. For both the S1 and S2 conditions, we placed an anodal electrode over the lesioned hemisphere and a cathodal electrode over the opposite hemisphere. We applied tDCS at an intensity of 2 mA for 15 min in both S1 and S2 conditions. We included two sham conditions in which the positions of the electrodes and the current intensity were identical to that in the S1 and S2 conditions except that current was delivered for the initial 15 s only. We found that GOT thresholds for the affected index finger during and 10 min after the S1 and S2 conditions were significantly lower compared with each sham condition. GOT thresholds were not significantly different between the S1 and S2 conditions at any time point. We concluded that dual-hemisphere tDCS over S1 and S2 can transiently enhance tactile discriminative task performance in chronic stroke patients with sensory dysfunction.

No MeSH data available.


Related in: MedlinePlus