| Project/Area Number |
12558100
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Biomedical engineering/Biological material science
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| Research Institution | Tohoku University |
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Principal Investigator |
FUTAMI Ryoko Tohoku University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (20156938)
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| Co-Investigator(Kenkyū-buntansha) |
KANOH Shinichiro Tohoku University, Graduate School of Engineering, Research Associate, 大学院・工学研究科, 助手 (00282103)
WATANABE Takashi Tohoku University, Information Synergy Center, Associate Professor, 情報ヘナジーセンター, 助教授 (90250696)
HOSHIMIYA Nozomu Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (50005394)
HANDA Yasunobu Tohoku University, New Industry Creation Hatchery Center, Professor, 未来科学技術共同研究センター, 教授 (00111790)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥7,000,000 (Direct Cost: ¥7,000,000)
Fiscal Year 2002: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2001: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2000: ¥4,700,000 (Direct Cost: ¥4,700,000)
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| Keywords | skin / Impedance / Electrical Stimulation / sensation / Electrode / Absolute threshold / 皮膚電気刺激 / 複素インピーダンス軌跡 / 皮膚インピーダンス / 感覚フィードバック / 時間変動 / 定電流パルス列 |
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| Research Abstract |
The relationship between absolute threshold and the parameters of an electrical equivalent circuit for skin impedance was examined with neurologically intact subjects. The equivalent circuit consisted of resistance Rp and capacitance Cp connected in parallel, plus resistance Rs in series to both.
As a result, for Ag-AgCl electrodes with electroconductive paste, variationsover time of the frequency characteristics of Rp and Cp were found to be similar to the changes caused by repeatedly stripping the skin. Values of Cp and Rp at 10Hz were found to relate to the absolute threshold with high correlation coefficients. Next we estimated the parameters of the equivalent circuit by measuring stimulus pulse current abd viltage waves of square-wave pulses using solid-gel electrodes. The absolute threshold increased with repeated electrical stimulation to the skin and decreased after adequate rest with no electrical stimulation. Rp decreased with repeated electrical stimulation and increased after rest, while Cp did not change. A significant correlation between Rp and the absolute threshold was observed. These results show that electrical stimulation to the stratum corneum affects both absolute threshold and skin impedance; they also indicate that real-time evaluation is important for stabilizing cutaneuos sensation elicited by electrical stimulation.
Possible reasons for decreasing Rp were an increase of ionic conductivity due to osmosis of electroconductive paste into the stratum corneum due to charge transfer. The increase of the threshold amplitude was considered to be the result of broadened current pad due to increases if ionic or electric conductivities in the stratum corneum. It is necessary to clarify the mechanism of those relationsship between threshold and impedance parameters.
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