Transactions of Japanese Society for Medical and Biological Engineering
Online ISSN : 1881-4379
Print ISSN : 1347-443X
ISSN-L : 1347-443X
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  • Keisuke KUBOTA, Yuki OKUBO, Yangsu LEE, Yukari KANEKO, Toshiaki TSUJI
    2021 Volume 59 Issue 1 Pages 1-6
    Published: March 10, 2021
    Released: April 03, 2021
    JOURNALS FREE ACCESS

    Upper limb motor function of patients with post-stroke hemiplegia is important for their independence in carrying out activities of daily living. Recently, research and development of upper limb rehabilitation robots to support reach training has been progressing. This robot training has been shown to be effective in improving motor function of the upper limb. However, because many of the robots are expensive and cumbersome, the venues in which such robots could be used were limited to hospitals and nursing care centers. We have developed a reaching device that is highly portable and easy to use at home. The main purpose of this study was to determine the effects of training with the reaching device in patients with chronic stroke hemiplegia. Nine subjects with hemiplegia participated in reach training two days per week for five weeks using the reaching device. We evaluated the results using Fugl-Meyer Assessment (FMA) and co-contraction between biceps brachii and triceps brachii muscles using the Co-Contraction Index (CCI). The results of FMA showed a significant increase in score after reaching training. On the other hand, no significant difference between pre-and post-training CCI scores was observed. The results showed that reach training was effective in improving comprehensive upper limb motor function. However, further investigation is needed to examine this in greater detail. In the future, it is necessary to identify subjects who respond to the training. The development of this reaching device has the potential to provide autonomous and effective home-based rehabilitation for patients with post-stroke hemiplegia.

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  • Akiko MIYAHIRA(SHINDO), Kazuko TADA, Takafumi SHIMIZU, Tadamasa TAKEMU ...
    2021 Volume 59 Issue 1 Pages 7-13
    Published: March 10, 2021
    Released: April 03, 2021
    JOURNALS FREE ACCESS

    Currently, healthcare workers have been very busy in their hospitals, and it is said that task shifting of healthcare workers will become more important in the near future. We also have discussed that the nursing workload is very heavy and their tasks should be shifted from nurses to other workers. Workload and workflow analyses are required to understand the actual nursing care situation. Therefore, time-motion study, a method of measuring nurses’actions and required time, has been conducted in nursing. However, time-motion study used so far requires the nurse to record his/her own nursing tasks or to record them with an investigator. Therefore, the time-motion study method is very burdensome in the clinical setting. On the other hand, hospital information systems (HISs) have been widely used in the clinical setting, and treatment orders by doctors and nursing orders are registered as medical treatment plans. At the same time, real-time execution input such as patient verification provides information of order execution including accurate execution time, which is accumulated as a medical record, and the data may represent most nursing tasks. In this study, for the purpose of improving nursing work, we tried to investigate the long-term nursing work volume using the order data in the hospital information system as a time-motion study. Specifically, we determined the nursing care time for each order data, and aggregated and analyzed the nursing care time by time of the day. As a result, it was possible to create some graphs showing the workload of specific nursing tasks by ward and to understand the task improvement effect of a ward.

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  • Ryuki NOHARA, Haruki TODA, Mitsunori TADA, Koji FUJITA
    2021 Volume 59 Issue 1 Pages 14-23
    Published: March 10, 2021
    Released: April 03, 2021
    JOURNALS FREE ACCESS

    Walking ability plays a major role in being healthy. Assessment of the walking ability of cane users in daily life will assist in rehabilitation implementation and health maintenance. We are developing a system for evaluating the walking ability of a cane user based on the motion of the cane. The purpose of this study was to analyze the correlation between the walking ability and the cane motion indicators that can be measured using an inertial measurement unit (IMU), and to identify the indicators that can be used to evaluate the walking ability. Twelve postoperative patients who had undergone total knee arthroplasty, uni-compartmental knee arthroplasty, total hip arthroplasty or bipolar hip arthroplasty were video recorded while walking along a 6m long straight line with a cane, and the resulting IMU data were recorded. We detected the timing of the initial contact and the terminal contact of the cane based on the jerk norm and the absolute angular jerk, calculated using the IMU data. We used gait velocity and step length as the walking ability indicators, and analyzed the correlation between these two indicators and the indicators detected using the IMU. These indicators were the angles in the sagittal and coronal planes of the cane at the initial contact and terminal contact, the acceleration and the jerk norms at the initial contact and terminal contact, the time of the cane touching the ground, and the maximum angular velocity while swinging the cane. Gait velocity was related to the acceleration and the jerk norm of the cane at the terminal contact and the time of the cane touching the ground. Step length was related to the cane angle in the sagittal plane at the initial contact and terminal contact, the acceleration norm and the jerk norm at the terminal contact, and the maximum angular velocity while swinging the cane. These findings proved that the IMU attached to the cane could measure the indicators related to walking ability.

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  • Hirotaka YAMASHITA, Ayumi MATSUURA, Masahiro ISHIKAWA, Naoki KOBAYASHI
    2021 Volume 59 Issue 1 Pages 24-30
    Published: March 10, 2021
    Released: April 03, 2021
    JOURNALS FREE ACCESS

    In recent years, 4K/8K video, and virtual reality (VR) have become widespread in the society, creating a viewing environment that is more realistic and immersive than conventional video. However, this has given rise to the problems of visual induced motion sickness (VIMS) with symptoms including nausea, dizziness, and headache. after viewing such video. In this study, we focused on VIMS with flat display under different ambient illuminance conditions, which is one of the important elements of visual discomfort. In the experiments, two types of video were viewed on a flat display, one with little motion and the other with dynamic motion, under different conditions of ambient illuminance in a dark room (3.5 lux) and a bright room (340 lux). Visual sickness was examined using subjective evaluation (Simulator Sickness Questionnaire and time series subjective evaluation) and physiological motion evaluation (movement of center of gravity and LF/HF). The subjective indicators confirmed that dark room conditions were more likely to result in motion sickness than bright room conditions. Moreover, the physiological indicators showed that the distance of movement of center of gravity was greater in the bright room than in the dark room.

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  • Mizuho TAGASHIRA, Takafumi NAKAGAWA
    2021 Volume 59 Issue 1 Pages 31-39
    Published: March 10, 2021
    Released: April 03, 2021
    JOURNALS FREE ACCESS

    In this paper, we present a method for facilitating the diagnosis of vascular stenosis in hemodialysis treatments. Sensory evaluation based on vascular sounds is usually used to identify vascular stenosis. However, skilled clinical judgement is required for this work. We applied the Mahalanobis-Taguchi Method to the assessment of vascular abnormalities. Mel-frequency cepstral coefficients, histogram kurtosis, and autocorrelation coefficients are used as features. The difference between normal and abnormal sounds is measured by Mahalanobis distance (MD). The performance of this method is estimated for 60 vascular sounds, with correct results obtained at a rate of 87%for abnormal sounds. The proposed method provides better discrimination than sensory evaluation. In addition, the relative change in MD values along the auscultation positions is similar to the result achieved by sensory evaluation.

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  • Tomohiro IWABUCHI, Takeyoshi DOHI, Kenta KUWANA
    2021 Volume 59 Issue 1 Pages 40-46
    Published: March 10, 2021
    Released: April 03, 2021
    JOURNALS FREE ACCESS

    Fetal-stage diseases, which may cause disabilities after birth, significantly decrease the quality of life of the fetuses. Improvements in imaging techniques enable early recognition of fetal-stage diseases. Reports indicate that some operable treatments during fetal development might improve physical function after birth. However, it is difficult to obtain follow-up biological information after fetal surgery because the fetus continues to develop in utero. Although implantable devices have been studied for measuring biological information, problems with biocompatibility, data communication, and power supply have been observed. To address these problems, we propose a method to measure biological information via pressure measurements using ultrasonic diagnostic equipment. The proposed method involves image analysis of a pressure-sensing membrane, whose deformation depends on the ambient pressure. In the proposed method, the deformation is imaged using ultrasonic diagnostic equipment and the displacement is calculated by image analysis. Finally, the calculated displacement is converted to biological information by focusing on its relationship with pressure. In this study, we prototyped a large-scale pressure-sensing module and evaluated the displacement of the pressure-sensing membrane within the module to confirm the working principle. The pressure-sensing module comprises a thin-film pressure-sensing membrane that is sandwiched between the body of the prototype module and the protective parts, thus forming a diaphragm-like structure with the body of the prototype module and membrane. The pressure-sensing module was fabricated using silicone rubber, and its dimensions were 30×30×30mm. Pressure was applied in the range of -22 to +22 kPa, and the displacement of the pressure-sensing membrane was calculated from ultrasonic images of the module. From the results, the displacement was confirmed to change linearly with the applied pressure, although the slope was non-linear in the pressure range of 0-10 kPa. These results indicate the feasibility of pressure estimation using the proposed method.

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  • Kumi HIROSE, Satoshi WAKABAYASHI, Takuya ONO, Makoto HIRAHARA, Kazuo Y ...
    2021 Volume 59 Issue 1 Pages 47-53
    Published: March 10, 2021
    Released: April 03, 2021
    JOURNALS FREE ACCESS

    This paper proposes a method to estimate brachial-ankle pulse wave velocity (baPWV) based on parameters extracted from acceleration plethysmogram (APG), the second derivative of photoplethysmography (PPG). The baPWV is to measure the arterial stiffness and clinically utilized to probe the presence of atherosclerosis. The measurement is made by the time delay between brachial and ankle pule waves at the clinical bench in a hospital. To explore the possibility to monitor the baPWV in daily basis at home, we examined the relation between baPWV and APG waveform. The simultaneous recordings of baPWV and PPG are made for 74 healthy subjects aged 30-69 (47.3±8.8) in supine posture. We have extracted five parameters from the APG, b/a, c/a, d/a, e/a and Tae, in which a-e are the extreme values of APG and Tae is the time interval between a and e.The new parameter estimation method using the third derivative of PPG waveform is introduced for the accurate parameter derivation, namely b, c and d which sometimes fuse each other to make the separation difficult in APG. Result showed the parameter Tae is the most important index for the estimation. The correlation coefficient between baPWV and Tae showed 0.569 (p<10-3). With additional parameter d/a, the prediction of baPWV by the multiple regression showed corrected coefficient of determination of 0.430. Setting the risk criteria of arteriosclerosis be baPWV>1.45 (M/S) the proposed prediction scheme achieved the risk detection rate of 0.917 with the false detection rate of 0.161. Although the estimation accuracy needs further improvement for the clinical use, the method will be utilized for the daily health monitoring for the early detection of the change in arterial stiffness.

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