生体医工学
Online ISSN : 1881-4379
Print ISSN : 1347-443X
ISSN-L : 1347-443X
49 巻, 6 号
選択された号の論文の30件中1~30を表示しています
研究
  • 根岸 大輔, 加藤 えみか, 太田 裕治, 山本 紳一郎, 河島 則天
    2011 年 49 巻 6 号 p. 789-797
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    The aim of this study was to characterize muscle property in patients with spinal cord injury (SCI). Ten SCI patients and ten age-matched normal subjects (Normal) participated to obtain ultrasound images of the calf muscles during slow passive ankle dorsiflexion (5deg/sec). Changes of the muscle fiber length (MFL), pennation angle (PA), displacement of deep aponeurosis (dAp), muscle thickness (MT), and displacement of muscle tendon junction (dMTJ) were quantified. Ankle angle and passive ankle torque were simultaneously recorded. The results showed that static PA and MT in SCI significantly decreased as compared to those in Normal. During passive ankle motion, MFL, PA and dAp showed different changes in response to ankle angle between SCI and Normal. These results suggest that substantial alteration of the muscle mechanical property would happen following spinal cord injury.
  • 大平 雅子, 須栗 一路, 野村 収作
    2011 年 49 巻 6 号 p. 798-804
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    (OBJECTIVE) The change in the secretion of stress-related bio-chemical substances, which are cortisol, immunoglobulin A (sIgA), and alpha-amylase, while asleep was regarded. As for the sample collection, we developed and proposed a saliva collection technique as a non-invasive and non-disturbing manner of sample collection while asleep, whereas the blood collection should impose greater psycho-physiological stresses to subjects. (METHOD) Subjects, 10 male university students, were instructed to take a 6-hour of sleep from 0:00 of the midnight to 6:00 in the morning at the environmental controlled room, where electrocardiogram (ECG) and blood pressure (BP) were measured, and saliva collection was made continuously in the time series. (RESULT) Salivary sIgA and alpha-amylase concentration obtained by saliva samples depicted a similar profile in the time series, i. e. gradually increase while subjects were asleep, and dropped to the initial level right after awakening. Meanwhile cortisol remained the same level while asleep and got started to increase right after awakening and reached at a peak around 40 minutes later. (CONCLUSION) We developed and proposed our own saliva collection technique for the purpose of non-invasive sample collection while asleep. As a developing result, the distinctive difference in the secretion of stress-related substances was illustrated;which might be derived from the difference in the stress-reaction pathways in our body.
  • 中尾 善明, 高田橋 篤史, 鎗田 勝, 藤元 登四郎, 田村 俊世
    2011 年 49 巻 6 号 p. 805-814
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    Remarkable progress in cognitive neuroscience has revealed the involvement of the prefrontal cortex and the orbitofrontal cortex in human working memory, but the orbitofrontal cortex is still one of the least understood regions in the human brain. To elucidate the contribution of the orbitofrontal cortex to human working memory, we studied EEG P300 activity in n-back task. We elicited early P3 around 300 ms and late P3 around 360 ms of P300 components in n-back ERP. The amplitudes of the respective peaks changed depending on the working memory load (0-back, 1-back, 2-back, 3-back). We used source analysis to evaluate the orbitofrontal cortex in P3 components. A source model was constructed with the sources seeded from fMRI meta-analysis of n-back task and additional sources in the orbitofrontal cortex and the visual cortex estimated with P100 and late P3 components in the n-back ERP. This source model had more than 99% of GOF (goodness of fit) in n-back ERP. It gave us an insight of brain activity at the positions where sources existed. Early P3 was mainly produced by the dorsolateral prefrontal cortex, the ventrolateral prefrontal cortex, the inferior parietal lobule, the medial posterior parietal and the visual cortex. Late P3 was mainly produced by the medial premotor, the lateral premotor, the frontal pole and the orbitofrontal cortex. The contribution of the frontal pole and the orbitofrontal cortex had peaks around 390 ms which were later than late P3 component. In this study, the method to evaluate the orbitofrontal cortex activity in n-back ERP was provided. Our results elicited the involvement of the orbitofrontal cortex in late P3 component of n-back ERP.
  • Ignacio HERNANDEZ, Tatsuhiko ARAFUNE, Nitaro SHIBATA, Haruo HONJO, Kai ...
    2011 年 49 巻 6 号 p. 815-828
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    This paper is concerned with the measurement system that optically records simultaneously membrane potential (Vm) and intracellular calcium (Cai2+) signals from a surface of Langendorff-perfused rabbit hearts, stained with voltage sensitive and calcium sensitive dyes. There are several publications about optical mapping system that deal with dual measurement, however the registration method used and evaluation accuracy is not explained in detail;most of the time it is just mentioned shortly and briefly. In addition, in order to be able to study different arrhythmia phenomena with accuracy, there is a necessity for simultaneous measurement using optical mapping system with high spatial and temporal resolution. In this paper, a new methodology in regard to the actual existing registration methods, which allow simultaneous measurement of two dynamic parameters from the same part of the heart, is developed, consisting of camera calibration, corresponding point-based registration using laser and Mutual information as a registration method for alignment respective optical fluorescence images. Evaluation of the registration of experimental data set in the Langendorff perfused rabbit heart, reveals that the accuracy of the registration obtained was RMSE=1.39±0.70 pixel on Experimental data set 1 and RMSE=0.76±0.38 pixel on Experimental data set 2, on the alignment process of the images.
  • 波田野 明日可, 岡田 純一, 鷲尾 巧, 久田 俊明, 杉浦 清了
    2011 年 49 巻 6 号 p. 829-835
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    Recent studies revealed that Ca2+not only regulates the contraction of cardiomyocytes, but can also function as a signal to stimulate ATP production by the mitochondria. However, spatio-temporal resolutions of current experimental techniques limit our understanding on this issue. This study employs our 3D cardiomyocyte model based on the finite element method (Okada et al. AJP 2005) and has been extended to include the detailed subcellular structure including the sarcolemma with t-tubule system, sarcoplasmic reticulum, myofibrils and mitochondria. Elementary processes involved in the electrophysiology, contraction and ATP metabolism are spatially arranged, and the multiple reaction diffusion equations for Ca2+and energy metabolites, and contraction were solved simultaneously. We specifically examined the effect of the gap distance between mitochondria and Ca2+release site. Our model revealed that increasing the gap distance induced a severe energetic derangement due to phosphate accumulation, resulting in contractile failure under tachycardic electrical pacing at 3Hz. Juxtaposition of the mitochondria to the Ca2+release site is crucial for rapid signal transmission to maintain cardiac energy balance. Realistic 3-D model of cardiac excitation-contraction and metabolism provides a powerful tool for the study of cardiac function by expanding the temporal and spatial resolution beyond the limit in experimental approaches.
  • 前川 義量, 阿部 武志, 秋山 庸子, 三島 史人, 白井 みどり, 西嶋 茂宏
    2011 年 49 巻 6 号 p. 836-842
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    In the field of nursing care for the elderly persons, understanding of their somatic sensation such as pain is very important for care workers to provide appropriate care. However, it is not always easy for elderly person with declined verbal function. Therefore, the objective evaluation method of pain intensity without verbal communication is required. In this study, pain evaluation system which can be used in daily life without verbal communication was developed. The system is noninvasive, because the information corresponding to pain intensity is extracted from facial expression. In order to digitalize the facial expression, the images of facial expression were extracted from the web cam on real time, and were analyzed sequentially. Pain stimulation test was carried out for healthy adults by dipping their hand into ice water (cold pressor test). A strong correlation was observed for young adults between pain face factor calculated from the facial expression digitalized by the system and sensory evaluation score of pain, VAS value. It indicates the validity of this system for estimation of pain intensity.
  • 山下 政司
    2011 年 49 巻 6 号 p. 843-849
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    There is autonomic specificity in emotion. Objective evaluation for emotion using physiological parameters has some possibilities of applications to the creation of comfortable environment, emotional movies or advertisements, to the human interface of the machine that obeys emotions, and to an understanding of emotions of the patients who cannot speak. As anger correlates with the stress, the psychosomatic disease and coronary heart disease, an understanding of the physiological features is important in medicine. But, the responses of blood circulation and autonomic nerve activities in anger, which is often felt in daily life, are not clear. Therefore, the measurement of blood circulation in anger was introduced, and the autonomic nerve activities and the minimum value of the cross-correlation coefficients between RSA and the respiratory wave (ρmin), which could associate with the autonomic nerve activity, were evaluated. Further, the correlation of the physiological parameters with subjective evaluation was investigated. Anger increased SBP/DBP and maintained their levels for a while. These reasons were estimated by the analysis of Pulse Wave Amplitude to the effects of sympathetic α-adrenergic vasoconstriction of the arteriole and slow metabolism of noradrenaline and adrenaline which must be elicited by anger. Anger did not change HR, but increased double product and maintained its level for a while. On the other hand, the correlation of ρmin with subjective evaluation was obtained. Therefore, ρmin is an effective index to objective evaluation for anger strength.
  • 中尾 善明, 高田橋 篤史, 鎗田 勝, 藤元 登四郎, 田村 俊世
    2011 年 49 巻 6 号 p. 850-857
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    In recent cognitive neuroscience, a lot of studies of the human working memory were examined, and EEG measurements during n-back task were often used. However, they were almost studied by ERP analysis. In the ERP study, time-locked components can be elicited, but non time-locked components such as the modulated brain oscillatory activity might be lost by an averaging procedure. To elucidate the contribution of the modulations of the brain oscillatory activity to the human working memory, we examined ERD/ERS analysis on the source waveforms during n-back task. Source waveforms were calculated from a source model which was constructed with the sources seeded from fMRI meta-analysis of n-back task and additional sources in the orbitofrontal cortex and the visual cortex estimated with P100 and P360 components in the n-back ERP. Our results suggested the network which included the prefrontal cortex and the parietal lobe had a contribution to human working memory process, and it was mediated by theta oscillatory activity.
  • 神谷 信一郎, 高田橋 篤史, 東 祐二, 関根 正樹, 藤元 登四郎, 田村 俊世
    2011 年 49 巻 6 号 p. 858-863
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    Motion-defined pattern perception is realized, when we watch an area composed of coherently moving dots surrounded by a “sand storm” zone of incoherently moving dots. In our preceding psychophysical experiments concerning this pattern perception with varied moving dot velocities, we found that at the velocity of 14.4deg/s, both perception of motion itself and of relevant pattern were carried out, whereas at the velocity of 43.2deg/s, perception of motion alone was performed. The measurements of magnetoencephalogram (MEG) to the same stimuli suggested that this pattern perception was processed in both ventral and dorsal portions of the occipital cortex with the latency at 250-290 ms. In order to achieve more precise identifications of activated areas and latency times by statistical treatments of MEG data, we employed the ERD/ERS (event related de-synchronization/synchronization) analyses in the present study and applied it to the grouped data of 8 participants, for the frequency band of 10-13Hz. The results of the analyses revealed that, under the condition of velocity 14.4deg/s, the significant ERD signals (p<1×10-6) were observed between 250-350 ms at the ventral portions in the primary visual cortex (BA17, BA18 and BA19, where BA:Brodmann area) and in the dorsal portion of the cortex (BA40). At the velocity of 43.2deg/s, the active areas with significantly enhanced ERD signals were found at BA37 and dorsal portion of BA19. No significant area was revealed for the ERS signals under condition of 14.4deg/s. These results suggest that the final processing of motion-defined pattern perception is performed at around 250-350 ms in early visual cortex including BA17, BA18 and BA19.
  • 滝本 遥, 野崎 一徳, 中村 匡徳, 藤垣 元治, 和田 成生
    2011 年 49 巻 6 号 p. 864-869
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    It is reported that patients who have undergone dental surgery of implanting prosthetic teeth often suffer from pronunciation disorders. In reference to the past studies which report a correspondence of the peak in a frequency spectrum between the fricative sound and the vibration of anterior teeth, it was hypothesized that the postoperative pronunciation disorders were attributable to a change in the vibration mode of anteriorly-implanted prosthetic teeth that have different elastic natures from natural teeth. The present study was designed to investigate effects of elastic properties of anteriorly-positioned prosthetic teeth on characteristics of its vibration and the emitted-sound. The flow channel was fabricated such that it morphologically simplified an oral cavity when sibilant/s/, one of the fricatives, is pronounced. An obstacle wall that is a model of anteriorly-positioned prosthetic teeth was made of four materials having different elasticity. The results demonstrated that the obstacle wall of different elasticity resulted in different modes of the vibration. However, the frequency spectrum of the emitted sound appeared to be almost the same irrespective of the elastic property of the teeth. Those results indicated less contributions of the teeth vibration to acoustic nature of the emitted sound, thereby suggesting that the postoperative pronunciation disorders is not due to a change in the vibration mode of prosthetic teeth at the anterior position.
  • 土井 俊祐, 木村 隆, 関根 正樹, 鈴木 隆弘, 高林 克日己, 田村 俊世
    2011 年 49 巻 6 号 p. 870-876
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    Clinical case reports are very important resources for a clinician to retrieve similar clinical cases when he encounters a difficult one to make a diagnosis or to decide a treatment. Of course in order to retrieve similar cases there has been much progress by using the computer with keywords from the era of looking into Index Medix in a library. However, the keyword retrieval is not always the best way. Even after keyword retrieval, we must sometimes select again from many chosen cases. It is ideal if the system tells us similar cases in order of degree of contents. We introduced morphological analysis and tf-idf method in this field to compare all the words in abstract and find similar ones in order of degree of similarity. We collected case reports from presentations of the local committee meeting of the Japanese Society of Internal Medicine (JSIM). These presentation meetings are well known in this country and more than 24,000 cases in the last decade have already been digitalized and stored. Now we started to provide Japanese physicians the option to retrieve for similar cases through the internet by using the text mining technique in JSIM homepage (http://www.naika.or.jp/) from June 17, 2011.
  • 小林 直樹, 石原 弘規, 田村 俊世
    2011 年 49 巻 6 号 p. 877-883
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    Pulse dye densitometry (PDD) is the method which obtains cardiac output (CO) easily, by injecting Indocyanine green (ICG) dye into a vein and measures plethysmogram using nasal wing clip sensor. Cardiac output is calculated by dividing the amount of injected ICG by the area under the first circulation curve of dye densitogram. PDD can also provide the mean transit time (MTT) which is average time until the indicator have arrived at the sensor position. As MTT has negative correlation with CO, we made regression models using MTT for calculating CO. We calculated CO from regression models and compared it to CO by the thermo dilution method (COtd). CO from regression models agrees well with COtd.
  • 加藤 俊和, 田口 侑人, 菅野 悠樹, 齊藤 俊, 吉永 崇, 桝田 晃司, 宮本 義孝, 千葉 敏雄
    2011 年 49 巻 6 号 p. 884-895
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    We have ever developed the method to realize active path selection of mircobubbles at the bifurcation of blood vessels. To enhance the density of microbubbles in the object vessel, our method introduces acoustic radiation force to the bifurcation of the blood vessel. To apply this method to an in vivo experiment, it is necessary to understand the three-dimensional shape of blood vessels and the distribution of bifurcations. In this study we developed a method to measure the distribution of bifurcations in blood vessel by combining optical position detection of ultrasound probe with the extraction of the blood flow in echograms. The shape of blood vessels is reconstructed in a graphical interface, where three-dimensional thinning algorithm was applied. As for unnatural end points in the reconstructed shape, we have developed an interpolation method to connect between nearest end points. In an in vitro experiment using an artificial blood vessel, we have confirmed that the two bifurcation points were detected with various experimental conditions. The proposed system succeeded to visualize blood vessels with vessel bifurcations in a human kidney.
  • 上野 彩子, 片山 統裕, 辛島 彰洋, 中尾 光之
    2011 年 49 巻 6 号 p. 896-903
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    It has been suggested that position- or diameter-selective recruitment of myelinated axons can be achieved by up-staircase-shape electrical nerve stimulation delivered from an extracellular electrode. However, so far, detail properties of the position- or diameter-selectivity of the stimulation have not been clarified. In this study, we investigated the spatio-temporal dynamics of myelinated axons in response to staircase-shape stimulation by numerical simulation of a compartmental model of rabbit myelinated axons. We found that the up-staircase-shape stimulation activates not only the targeted axons but also the ones close to the electrode by anodal break excitation;this property would degrade the distance selectivity of the stimulation. By considering the mechanism of extracellular electrical stimulation, we developed down-staircase-shape stimulation which can achieve selective activation of targeted axons without generating anodal break excitation near the electrode. Systematic simulation revealed that the down-staircase stimulation is better than the up-staircase one in terms of distance-selectivity of axon recruitment. However, diameter-selectivity of both stimulations was not sufficient.
  • 小寺 宏尚, 八城 正知, 大橋 篤, 片山 俊郎
    2011 年 49 巻 6 号 p. 904-910
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    The concentrations of hepatitis C virus (HCV) are reported to be lower in dialysis patients than those in HCV-positive non-dialysis patients. In order to explain this clinical view, we modeled the adsorption phenomenon of the HCV antigen in the dialysis membrane surface with the Langmuir's adsorption isotherm, and proposed the mathematical model in consideration of the adsorption effect of HCV by the dialysis membrane. Therefore we conducted the recirculation experiment with various dialysis membrane in vitro system, and conducted curve fitting based on that result in order to examine the validity of this model. We perfused albumin (Alb) solution containing HCV and physiological salt solution containing HCV in the blood circuit connected to a regenerated cellulose (CU) membrane, cellulose triacetate (CTA) membrane, polymethylmethacrylate (PMMA) membrane, or polysulfone (PS) membrane, and measured quantities of HCV antigen and Alb over time. Further to consider the effect of Alb on the dialysis membrane, we analyzed the quantity of adsorption of the HCV antigen under Alb mixture and under Alb free in each dialysis membrane, and calculated the coefficient of adsorption rate and the quantity of the maximum adsorption of the HCV antigen for every dialysis membrane. The quantity of HCV antigen adsorption by PS membrane was 26.8 fmol under Alb solution and 29.0 fmol under physiological salt solution, was the maximum rather than other dialysis membranes, and the coefficient of adsorption rate was the fastest with PS membrane. In conclusion, the usefulness of the model which we created was suggested and we determined the useful dialysis membrane as reduction of the amount of HCV antigens in HCV-positive dialysis patients.
  • 村山 敏夫, 遠藤 勇気, 木竜 徹, 牛山 幸彦
    2011 年 49 巻 6 号 p. 911-917
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    Skiing technique is required to cope with topographical changes in snow ground condition. Besides, muscle strength is required to endure muscle fatigue in a high-speed environment, especially during a critical phase such as consecutive ski turns. Thus, objective evaluation is important for improving skiing technique and obtaining high performance. In this study, we analyzed the performance of actual skiing with different technique levels, focusing on leg muscular activities during ski control and postural control, in relation to the movement skills. We prepared the feature parameters estimated from surface EMG signals and knee joint angles at each turn, then, analyzed the performance by a cross-correlation for evaluating the relationships between the feature parameters. The results showed that the standard deviations of parameters in high-performance skiers were small. Cluster analysis with the k-means method, further, revealed muscle activity patterns in a three-dimensional scatter distribution. This approach leads to an objective evaluation on a ski ground that allows effective training and protects sport injury.
  • 北野 智哉, 宮越 貴之, 小林 信治, 得能 敏正, 山崎 健二, 岩崎 清隆, 梅津 光生
    2011 年 49 巻 6 号 p. 918-924
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    A durability test of the implantable Left Ventricular Assist System EVAHEART was conducted to demonstrate that the EVAHEART Blood Pump can be run for 2 years without failing. This testing was useful to indicate potential for BTT and possibly DT applications. We developed a custom durability test mock circulation loop which generates a pulsatile flow simulating the native left ventricle. This mock circulation loop includes components which mimic the left ventricle (LV chamber) and compliance in the aorta (aortic column), and a loop which connects the blood pump to both the LV chamber (inlet) and the aortic column (outlet). The LV chamber has two one-way valves and a linear motor connected to a rolling seal, allowing it to generate pulsatile flow. The blood pump speed was tuned to achieve clinically relevant flow, based on the need to supplement a failing heart. The simulated heart rate (stroke rate of the linear actuator) cycled through 3 different settings each day to simulate changes in patient activity level. The sample size for the durability test was set to 18, and the test duration was 2 years. During the test, no critical blood pump failures were observed. There were no indications of significant decrease in pump performance or seal performance. Furthermore, no symptoms of failure, such as abnormal wear, were observed. In conclusion, the durability test successfully demonstrated that the EVAHEART Blood Pump achieved component reliability at a minimum of 90% reliability and 88% confidence interval over a mission life of two years.
  • 瀬野 晋一郎
    2011 年 49 巻 6 号 p. 925-931
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    The author has already reported the current perception threshold (CPT) of skin surface using the quantitative evaluation system for pain (Pain Vision®). CPT can provide the useful information for the diagnosis of the peripheral neuropathy and the related diseases. In this study, CPT on the oral (gum and tongue) and the lip region were measured using the same system. The oral and the lip region are influenced to the much nerve which is branched from trigeminal nerve. The grasp of these neurological functions is essential to an evaluation of these peripheral nerve functions, such as a taste disorder or hyperesthesia, and the depth of local anesthesia. The purpose of this study is to determine the standard value of CPT in healthy person as the control CPT range on the oral and lip regions. CPT were measured on the oral and the lip region of 120 healthy young subjects (male:60, average age 22.36, female:60, average age 22.0) by the electrical stimulation (pulse width:0.3ms, 50Hz). As the results, measured CPT of the oral cavity and lip regions is distributed over the relatively small range, but shown the significant differences in sex and the position in correspondence with nerve system. The CPT of the tongue showed the great difference between measurement positions traced to the dominant nerve. The center and the base of tongue showed 2-3 times higher CPT values than the tip of tongue CPT.
  • 阿部 誠, スガイ テルマ ケイコ, 吉澤 誠, 本間 経康, 杉田 典大, 清水 一夫, 後藤 萌, 稲垣 正司, 杉町 勝, 砂川 賢二
    2011 年 49 巻 6 号 p. 932-938
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    The implantable cardioverter-defibrillator (ICD) is an effective therapeutic device for rescuing patients with cardiac diseases from death caused by life-threatening arrhythmias. The authors previously have proposed a detection algorithm of life-threatening arrhythmia with a multiple regression model. In this research, we have developed the algorithm so as to accurately classify cardiac rhythms and to reduce in the computational time with a microcontroller used in the ICD. The experimental results showed that the proposed method kept a high accuracy to detect cardiac rhythms. In addition, the validation of implementation of the proposed algorithm in the microcontroller indicated that the result of detection of cardiac rhythms could be attained within computational time of 60 ms. For the practical application, it is necessary to evaluate the power consumption of the ICD working with the proposed method.
  • 辻村 真一, 杉浦 敦, 山岸 丈人, 筒井 達夫, 山海 嘉之
    2011 年 49 巻 6 号 p. 939-945
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    We have developed an intelligent sensorized artificial heart, Smart Artificial Heart, for safe and effective medical treatment to artificial heart patients. In order to easily achieve the sensing functions of the Smart Artificial Heart in existing artificial hearts without modification of the original hardware, the purpose of this study is to develop an integrated sensor unit (ISU) which is applicable to various artificial hearts by incorporation of the noninvasive sensor systems of the Smart Artificial Heart. By only attaching the ISU to the surface of the blood circulation tube between the patient's aorta and the artificial heart, we can noninvasively and continuously measure the following five data:blood temperature, blood flow, blood pressure, hematocrit (Hct), and arterial oxygen saturation (SaO2). We evaluated its measurement accuracy in mock circulatory experiments and an animal experiment, by comparison with commercial instruments. As a result, the measurement errors of the temperature, the flow, and the pressure were less than 0.4°C, less than 0.4 l/min, and less than 8 mm Hg, respectively. Then the measurement errors of the Hct and the SaO2 were less than 0.8 Hct% and less than 0.3 SaO2%, respectively. In conclusion, we confirmed that the ISU has performance to noninvasively and continuously monitor the conditions of artificial heart patients.
  • 飯島 淳彦, 小杉 剛, 木竜 徹, 松木 広介, 長谷川 功, 板東 武彦
    2011 年 49 巻 6 号 p. 946-951
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    We investigated an effective method for evaluating chronic stress in humans by using pupillary responses to visual motion stimuli. Nine subjects watched movies including 18 short video movies (duration:10s in each). The pupil diameter responding to the movies were measured with a video oculography and calculated the difference between the maximum and minimum pupil diameters responded to the stimuli was highly correlated with the salivary α-amylase (R=-0.76, p=0.018) activities. The sympathetic nervous system is activated by a stress and secretes the salivary amylase. We found that there were some autonomic different responses in the stress subject from pupillary and salivary observations. These phenomena were clearly observed under the visual movie stimulation which was able to reveal the steady pupillary responses.
  • 神谷 信一郎, 片見 裕司, 関根 正樹, 田村 俊世
    2011 年 49 巻 6 号 p. 952-956
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    As a screening test of the dementia, such neuropsychological tests as the mini mental state estimation (MMSE) test are usually employed. A problem in MMSE test is that it takes considerably long time, accompanying substantial loads to subjects. We examined whether a digit span task could be an alternative screening test of easier and less time-consuming means for dementia patients. In this task, participants were asked to remember a series of random digits (from 0 to 9), individually displayed on a screen for 2 sec and thereafter to input them on a touch panel. The number of figures was increased from 3 to 7 by one place and vice versa. We recorded the maximum number of figures correctly recalled (Nmax) and the reaction time (RT) until the first digit input. The experiments were carried out by participants clustered into three groups;(1)the healthy young group (n=15, 22±1.15 years old). (2)the healthy elderly group (n=10, 68.5±4.5) and (3)the senile dementia group (n=13, 76.6±6.9). Only participants in the dementia group took the MMSE test. Nmax of dementia group (4.46±0.94) was significantly lower than that of healthy elderly group (6.10±0.62) and of young group (8.71±0.96) (F(2, 34)=84.00, p<0.01). In all groups, RT was significantly elongated with the increased figures of displayed digits, although the slope of the regression line of the dementia group was 2.5 times as much as those of other groups. Regarding the dementia group, the MMSE scores of individual participants were found to be significantly correlated with Nmax (r=0.82, p<0.01) and with RT of 6 digits number (r=-0.64, p<0.05). These results suggested that the digit span task could be a feasible and reliable screening test for dementia.
研究速報
  • 鈴木 明宏, 石井 賢治, 永富 良一
    2011 年 49 巻 6 号 p. 957-961
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    The amount of daily physical activity is strongly associated with the prevalence of life-style associated diseases. Therefore, maintaining an appropriate level of physical activity is recommended for life-style associated diseases. Walking is a type of physical activity which most of people are capable in daily lives without any instruction. Recently a new style of walking using ski poles, namely Nordic Walking (NW) is becoming popular. NW is characterized by wide stride length due to thrust force produced by ski pole actions. Widening stride length may contribute to increased walking speed and consequently to increased exercise intensity in NW as well as in conventional walking. Estimation of walking speed and stride length using a wearable accelerometer may enable the users to evaluate their activities. Seventy-two healthy adult volunteers (age 18-78) were asked to walk a 40 m-stretch on a flat ground with or without NW ski-poles. Three dimensional accelerometer was firmly attached to the center of low-back with a strap. Walking speed, stride length and cadence was calculated from the recorded movie data. A best-fit liner equation to estimate walking speed from acceleration, cadence, and body height was generated. Cross validation of the estimated walking speed revealed minimal errors (RMS 5.14m/min, 5% of the mean). We propose a practical method to estimate walking speed, cadence and stride length from three axis acceleration sensor signal.
  • 浅野 裕俊, 熊谷 淳, 井出 英人
    2011 年 49 巻 6 号 p. 962-967
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    Recently, as Japan is rapidly aging, an increase of aged people who require nursing care is expected. Especially, in case of people requiring intensive nursing care due to severe difficulty in communication by means of speech or gesture, objective evaluation of their emotional states as well as physical or mental pain is required. Therefore, it is important to establish the method for objective evaluation of feelings. Functional neuro imaging, especially near-infrared spectroscopy (NIRS), has been used so far to evaluate objective evaluation of feelings. However, there are few studies that evaluated feelings by focusing on complexity of the brain where high-level information processing is performed. There are also few studies that evaluated feeling-related responses in the prefrontal region that is known to be related to feeling processing. Unpleasant emotion is an extraneous factor of feelings. Therefore, we aimed to preliminarily evaluate unpleasant emotion quantitatively by using the lyapunov exponent that is an index of chaotic states. The lyapunov exponents calculated from temporal change of oxygenated hemoglobin concentration in the prefrontal region were compared between during the resting state and during listening to an unpleasant sound. As a result, the lyapunov exponent during listening to an unpleasant sound was significantly lower compared with that during the resting state. There was moderate correlation between the lyapunov exponent and the unpleasant psychological value measured using a visual analog scale (VAS). Especially, correlation coefficient was -0.50 at the prefrontal channel. These results suggest that our method is a useful index for emotional evaluation.
  • 野川 雅道, 山越 健弘, 松村 健太, 田中 志信, 小川 充洋, 本井 幸介, 山越 憲一
    2011 年 49 巻 6 号 p. 968-976
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    A new method is presented for the indirect measurement of systolic (SBP) and diastolic blood pressure (DBP) in the radial artery. We use the volume-oscillometric method with a wrist cuff and then, utilizing the photo-plethysmograph (PPG) signal together with cuff pressure measurements, we derive pressure-volume curves (PVC). The principle of this method, named “PVC inflection-point method”, is to identify the indirect SBP and DBP using the inflection-points of envelope curves overlaying respectively the lower and upper points of the photo-plethysmographic pulsation signals superimposed on an arterial volume signal during the volume-oscillometric procedure. The accuracy of the method was evaluated by comparison with measurements from arterial catheterization in two healthy subjects. During the test procedure, a prototype PPG sensor for the PVC inflection-point method was attached to the left wrist, and arterial catheterization of the right radial artery for was performed to obtain simultaneous blood pressure recordings. The Bland-Altman plots for the comparative analysis showed good agreements between the two methods for both SBP (+2.3±7.7 (mean±S.D.) mmHg) and DBP (-1.8±6.4mmHg) measurement. We conclude that the proposed PVC inflection-point method appears promising to determine indirect SBP and DBP values with appropriate accuracy for convenient and practical use.
  • 花田 智, 関根 正樹, 田村 俊世, 新地 友和, 上田 美香, 藤元 登四郎
    2011 年 49 巻 6 号 p. 977-982
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    The interval training (IT) is recommended for patient with cardiovascular disease who cannot accomplish of endurance training (ET) because of leg fatigue. However, there were few reports about a change in the autonomic nerve activation during the IT. The aim of this study was to estimate changes in autonomic nerve activation during the IT and ET. The eight cardiovascular patients performed into the IT and ET. The IT was performed into 10 bouts of exercise with a pause phase of 2 min. The length of the exercise phase in IT was 1 min. ET was performed at a constant intensity for 10 min. The workload was set at the anaerobic threshold. The evaluation indices were systolic blood pressure (SBP), heart rate (HR), and the high frequency (HF) component of power spectra calculated from the R-R interval corresponded to parasympathetic nerve activation. As the results, All indices expect HF in the IT and ET increased concomitantly with the exercise start. Finally, SBP and HR in ET, and HF in IT increased. From these results, sympathetic nerve activation during IT might be a tendency to low in comparison of ET. Furthermore, IT might activate the parasympathetic nerve activation.
  • 笹山 瑛由, 小林 哲生
    2011 年 49 巻 6 号 p. 983-988
    発行日: 2011/12/10
    公開日: 2012/04/10
    ジャーナル フリー
    Most brain computer interfaces (BCIs) that classify right/left wrist bending movements or their imageries measure and learn the electroencephalogram (EEG) rhythmic modulation involved in sensorimotor activities. However, the issue is that the BCIs do not perform well when the brain activities that do not exist in the learn process occur outside the sensorimotor area. To resolve the issue, we propose the BCI that adopts the reconstructed signal power in the activated region in which the subject performs the movements as features for a linear classifier. The activated region for each subject is identified using functional magnetic resonance imaging (fMRI). We adopt a linearly constrained prewhitening spatial filter for reconstruction of signal power, which is suitable for reconstructing event-related desynchronization/synchronization signals and for existing highly correlated signals. The result is that the proposed BCI that adopts an EEG spatial filter with linear constraints of fMRI activated regions obtains higher accuracy than previous methods.
生体医工学シンポジウム2011
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