Determination of Electrical Parameters for Skin during Galvanic Skin Reflex from Continuous Measurement

Skin impedance satisfies the Cole-Cole arc's law. The change of skin impedance during GSR (Galvanic Skin Reflex) can be expressed by the change of equivalent parallel resistance approximately. Using these characteristics, the complicated change of skin impedance during GSR can be determined continuously from the measurement value in one frequency point

Measurement of Emotional Response by Similarity in Patterns of Galvanic Skin Reflex

There is no doubt that many people feel the peace of mind or the pleasures of senses in appreciating music. But the estimation of the effect is very difficult and the objective estimation can be hardly done. This study proposed the objective estimating method of human emotion utilizing galvanic skin reflex (GSR) which reflects a human psychological activity. In this method, not by individual response, but by the series of response and pattern of appearance of GSR, the emotional response under appreciating music was investigated. In the case of appreciation of the same classic music to several subjects, the individual GSR responses are random and remarkable characteristic could not be find on the results. However, on the patterns of appearance of GSR, the patterns obtaining from the same generation are much similar each other and the patterns obtaining from different generation are less similar. It was cleared that the same music gave different effect on different generations

Parameters for Analysis on Distributed Circuit Properties of Etched Alunimum Oxide Film

The distributed circuit properties based on pores in the etched aluminum oxide film of the electrolytic capacitor have been analysed by the mathematical equation. This paper proposes the selection and the determining method of the parameters appearing in the analysis

A venous occlusion plethysmography using a load cell as the sensing element

An application of the load cell as a sensor in venous occlusion plethysmography is presented. In this method the limb volume changes that follow venous occlusion are converted into water volume changes using a water tank for volume change detection. The hydrostatic pressure, as well as the water surface level, is measured and used for the calculation of the volume change. By using this method the influence of water pressure on limb blood flow, as well as drift and leakage of the sensing element, is avoided. The load cell has the advantage of measuring the weight of the displaced water volume, which simplifies the design principles of the plethysmography. The plethysmography is found to be sensitive, highly linear, and easy to handle. It has been evaluated in several subjects, and the results of these studies are in agreement with earlier results </p

Influences of the Skin Impedance as the Interface in Bioelectric Potential Measurement

In the case of non-invasive measurement of bioelectric potential from body surface, the influence of the skin impedance has been investigated by using strict equivalent circuits of skin impedances. The relationship between the characteristic of skin impedance and the wave distortion was made clear. Furthermore, in the case of electrocardiograph, the shift potential of indifferent electrode to standard potential was obtained by means of simulation, and the distortions caused by connective resistances of a central terminal and skin impedance were quantitatively explained

Variations of parameters of bioelectrical impedance during upper limb movement

これまでに生体電気インピーダンスを用いて身体運動の解析を行ってきた。インピーダンスの変動原因は測定部位の等価断面積変化および貯血量変化と説明できるが，直接的に断面積変化や貯血量変化を測定することは困難であるため，その変動原因の定量的な検討は不十分であった。そこで，本研究では上肢運動に伴う生体電気インピーダンスの変動原因を生体の等価回路のパラメータの変動で説明する。インピーダンスのモデルはCole－Cole型であり，等価回路は，細胞外液抵抗Re，細胞内液抵抗Ri，分散の特性周波fm　fm，緩和時間の分布の程度を表すα，βの独立した5パラメータで表現した。 上肢の肘関節および手関節の屈曲運動野に伴う前腕部および上腕部の電気インピーダンスを測定した。まず，電気インピーダンスの等価直列抵抗Rの変動率をパラメータの変動率で線形近似し，その信頼性と各パラメータ変動のRへの影響を確認した。Rへの影響はReとRiが支配的であるが，測定部位や運動の違いにより，それぞれの影響が異なることを示した。これは測定部位の筋活動状態の違いを表すものである。さらに，肘関節最大屈曲におけるRの変化にはfmの変化が大きく依存しており，上肢運動のインピーダンス変化には細胞膜の分極特性の変化も影響していることを明らかにした。本研究の結果は，運動強度の違いや疲労状態における身体運動評価に有意義である。We have proposed new biodynamic analysis methods using bioelectrical impedance. Variations of human limb electrical impedance during biodynamics were caused by variations of equivalent cross sectional area of muscle and variations of blood volume. However these variations could not be directly measured. Therefore quantitative discussions about relation between the impedance and these variations have been insufficient. In this work, we explained variations of the impedance with variations of parameters of an equivalent circuit. The model of impedance was Cole-Cole type. The equivalent circuit consisted of five individual parameters as follows : extracellular fluid resistance, 'Re', intracellular　fluid　resistance, 'Ri', characteristic frequency of dispersion, 'fm' and parameters of dispersion of relaxation time, 'α' and 'β'. Impedances of forearm and upper arm were measured with four electrode method during flexion and extension of joints in upper limb. The ratio of variations of equivalent series resistance R was linear-approximated using the above mentioned parameters. The influences of parameters on variations of R was confirmed. R was strongly influenced by Re and Ri, However there were differences between influence of Re and that of Ri in difference measured part and difference joint movement. This showed the conditibn of the muscle. In case of the maximum　flexion of the elbow joint, R of upper arm was influenced by fm. This means that a polarization of cell membrane changes and influences impedance during movement. These results are significant in evaluation of biodynamics including difference of strength of movement and condition of exhaustion

Development of measuring method for softness of epidermis using rotational step response

We have proposed a new measuring method for the softness of epidermis using rotational step response. It can be proceeded that horizontal torsional step is given periodically to the human skin surface by rotational step motor. Then dynamically epidermal characteristic is abstracted selectively from the human skin minimizing influence of the subcutaneous tissue. The cylindrical rotor is attached to the shaft of step motor and its external area is surrounded by the cylindrical guard ring; therefore, only human skin surface of inside the guard ring is screwed periodically by its rotor. At this moment, viscoelasticity of the epidermis is evaluated from analyzing the inducting coil of the step motor. The waveform of voltage of inducing coil can be characterized by overshoot P1, damping ratio D and undamped natural frequency &#969;n. The softness Ks that indicates viscoelasticity of the epidermis can be calculated from these parameters. Many experimental results showed that the softness Ks corresponds to the human sense and it is rational as a parameter for the human skin characteristics. This system is very useful as the measurement can be done easily, in vivo, and non-invasively. It also can be constructed simply without special mechanical sensor because step motor acts as not only driving but also sensing </p

Principle of Biodynamic Analysis Using Human Limb Electrical Impedance

This paper describes a new measurement method and principle of detection of biodynamics using bioelectrical impedance method based on four-electrode technique with sinusoidal constant current. This method uses a human body itself as a part of the sensor. First, we show a bioelectrical impedance measuring device and the change of bioelectrical resistance is measured in human movement. Second, we proposes a principle of detection of biodynamics based on correspondence of magnitude, form and stability of movement to impedance waveform. Hence we can use this method for the judgement of sports skill using the impedance characteristics

Electrical Cell-substrate Impedance Sensing (ECIS)法を用いた培養細胞の微細挙動の定量的評価法 - 細胞-細胞間隙と細胞-電極間隙の評価 -

We have proposed a mathematical model for the micro-dynamics for cultured cells measured with ECIS system for the detection of nanometer-order dynamics of cells cultured on a small gold electrode and could separately evaluate cell-to-cell distance (A) and cell-to-substrate distance (h). For wide applications of this method, we constructed mathematical models which express cell-to-electrode impedances for some kinds of confluent conditions. Based on this mathematical model, we defined new parameters S(A) and S(h) in order to evaluate cell-to-cell distance and cell-to-substrate distance. As the application, we investigated the effect of X-irradiation to bovine aortic endothelial cell (BAEC). We analyzed the micro-dynamics of cells from the impedance of BAEC before and after X-irradiation. It was proved that the stimulation of 100 Gy X-irradiation to the BAEC resulted in the large scale of increase in the cell-to-cell distances (A), and the slight increase in the cell-to-substrate distances (h) accompany with continuous fluctuations.[背景] Electrical Cell-substrate Impedance Sensing (ECIS)は培養細胞の電気的計測により,その微細挙動を評価する工学的手法である｡我々はECISを用いてこの微細挙動を細胞-細胞間隙と細胞-電極間隙に分離して推定することが可能な数学的モデルを提案してきた｡本研究ではこの数学的モデルを使用して,Ⅹ線を照射した牛大動脈内皮細胞(bovine aortic endothelial cell : BAEC)の微細挙動の経時変化を評価した｡ [方法と結果] ECISシステム(Model 1600R Applied BioPhysics)を用いてBAECのコンフルエント到達前後で計測を行い,数学的モデルを構築した｡このモデルは細胞の微細挙動を検出するために重要な周波数レンジである1-10kHzにおいて測定結果とよく一致し,Cole-Cole円弧則に従う｡さらに細胞-細胞間距離Aの増減に対応する校正定数S(A)と細胞-電極間距離hの増減に対応する校正定数S(h)を導入し,ベクトルインピーダンスの変化に対応した値を算出することで細胞の微細挙動を評価することとした｡次に本法によりX線(150kV, 100Gy)を照射したBAECの微細挙動を評価した｡Ⅹ線照射細胞では時間経過と共に抵抗成分の変化が支配的なインピーダンスの減少が確認された｡この現象はS(A)の大きな増加とS(h)の微小な減少をもたらした｡このパラメータの変化は細胞間隙が拡大したことを示しており,Ⅹ線照射による細胞内損傷により細胞密度が低下したと考えられた｡ [結論] 本法は培養細胞の微細動態の変化を細胞-細胞間隙と細胞-電極間隙に分けてリアルタイムに定量評価することが可能であり,各臓器の細胞レベルでの薬物の治療効果や Ⅹ線に対する耐性の評価に適応できるものと考える

生体電気信号の計測システムへの電力線からの誘導障害に関するインターフェイスモデル

A modelling of interface construction relating to power-line interference phenomenon was described. Source of interference was displacement currents which flowed from AC power-line configuration (APC) to a model. The interference depends on some factors: distance between the APC and a model ; length of unshielded leads ; position of the APC in vertical or horizontal direction ; and skin-electrode impedances which were balance or unbalanced. The position of APC and skin-electrode impedances were important in contributing of the interference. The interference was still large even though skin-electrode impedances were balance. This was caused by the disagreement in two displacement currents. It was overcame by adjustment of APC in vertical direction. As a result, total interference would be very small or zero. The result shows that interference in ECG signal recording can be eliminated to about 10 μV. Although interference of power-lines is a complicated phenomenon, the problem is easier to understand by using this modelling.生体電気信号の測定における電力線からの誘導障害についての研究が多く報告されているが，この現象についての説明が十分なされていなかった。本研究では，この現象を簡単なインターフェイスモデルを用いて説明した。誘導障害の原因として，電極の導線が作るループ内に発生する誘導起電力，システムの変位電流，生体アンプ内で発生する雑音等があげられる。本研究においては，電力線と導線との静電結合によってその間を流れる変位電流と被験者と電極間のインピーダンスに注目した。この変位電流による誘導は，いくつかの要素に依存している。それらは，・被験者と電力線との距離，・被験者に対する電力線の方向，・導線のシールドされていない部分の長さ，・被験者と電極間のインピーダンスである。そこで，被験者と電力線との距離や導線のシールドされていない部分の長さなどを変化させて，心電図の測定を行った。被験者と電極間のインピーダンスを調整できるように，可変抵抗を用いたRC並列回路をそれぞれの導線に直列に接続した。また，導線のループに発生する誘導起電力をできるだけ小さくするために，導線を互いに撚ってループ面積を小さくした。誘導雑音は，以下の場合に大きくなった。・電力線の距離が近い。・導線のシールドされてない部分が長い。・被験者と電極間のインピーダンスが大きく，不均衡である。また，被験者と電極間のインピーダンスを等しくした場合でも，誘導雑音が観測された。電力線の位置により各導線と電力線との静電結合状態が異なり，各導線に流れる変位電流が等しくないことが誘導雑音の原因であることを示した。本研究では被験者と電極間のインピーダンスおよび変位電流による誘導雑音の影響について検討した。この現象の理解は誘導障害の除去に大変有益なものである