Dementia progresses to healthy people, PCSD, MCI and Dementia. The initial research was the development of curative for Dementia. Various imaging techniques and neuropsychological tests for diagnosis, non-drug therapy, care technologies such as robots, etc. were the research subjects. Recently, when research on curative have been stalled, the entire research has been paradigm-shifted toward pre-Dementia stage. Therefore, the research subject of BME on Dementia should be also moving toward the prevention of dementia, because I believe that synergistic effects with other technical fields are important in pursuing results. Finally, as an example, I would like to introduce the Neuropsychological Test named CWPT, which enables classification of minor brain functions before Dementia. This test has already gained evidences and has been put to practical use as a screening for local residents in Japan. We have created English version of the test. If you are interested, please contact me.

At nursing care sites, life programs are implemented for improving the QOL of facility users. It is important to carefully examine the QOL items for each user, create and implement the effective life program based on this. However, facilities are busy on a daily basis, and it is not possible to devote sufficient time to developing a life program that considers the role of user. Therefore, in this study, we first selected the QOL items from the areas of "activity" and "participation" of ICF and scrutinizing based on a questionnaire survey of 355 facilities. Then, we developed a computer system that automatically generates a life program using determined QOL and creates a database of the results. This system can be used from the browser that is usually used to improve the convenience at each facility. In this paper, we discuss the details of the developed system and its use.

We have reviewed recent evidences of music-based therapeutic intervention for prevention of dementia and mild cognitive impairment which were reported in journals. We will present the results focusing on effects of active music therapy and playing musical instruments. We have been developing a novel accessible electronic musical instrument Cymis. We will outline our pilot study of applying Cymis with touch panel or switch to moderate-sever dementia patients in a nursing home as well as healthy seniors.

Home hemodialysis (HHD) is an ideal dialysis modality, by which the patient can make its dialysis program according to its own life style with a sufficient dialysis dose. HHD is rather safer than in in-center HD because the ultrafiltration volume per unit time in HHD are lower than those of in-center HD. In spite of these benefits, only 0.2% of all dialysis patients in Japan are treated by HHD. The major reasons for that are the anxiety for probable treatment-related troubles in home and the lack of an accompany person. If artificial intelligence could evaluate the severity of the trouble based on the bio-medical information, it could make a warning to the patient and the medical staffs in the hospital, or in a case to the security service. If we could complement the safeness of HHD with bio-medical engineering technologies, we could expand its benefits to more dialysis patients.

Bruxism is a symptom in which one grinds, gnashes, or clenches one's teeth unconsciously. It may cause the teeth to be chipped, which can result in temporomandibular joint disorder. Pseudo clenching is masseter muscles' excessive tension without tooth contact, which is difficult to distinguish from bruxism. This study was performed to detect bruxism and pseudo clenching automatically by machine learning. Single-stream or multi-stream Hidden Markov Models (HMM) for each of the three classes (bruxism, pseudo clenching, and others) were trained with Mel Frequency Cepstral Coefficients (MFCC) calculated from EMG and acoustic signals from 12 healthy adults. The averaged F measure, calculated with cross-validation, was used to evaluate the model. The F measure with EMG only was 77.2±8.1%, that with acoustics only was 60.1±16.0% and that with both features was 81.7±8.5%.These results indicated that a rather good performance of bruxism detection was realized, but further improvements are needed.

Background: Moxibustion is an alternative medicine performed by burning moxa at a specific part of the body. However, there has been no quantitative analysis of whether moxibustion induces physiological responses in previous studies. In this study, we investigated the thermal effects of moxibustion on cardiovascular responses. Methods: Twenty healthy volunteers participated in this study. Moxibustion treatment was applied to the lower leg (Zusanli acupoint). Heart rate(HR), blood pressure(BP) and skin temperature(ST) were measured continuously for 2 min at rest and 6 min at moxibustion. Results: HR significantly decreased (64.3±7.5 to 62.3±1.3bpm, p=0.005) when ST reached a maximum (45.0±10.1°C) by moxibustion. There was no significant change in BP, and the bradycardic effect was also observed when ST was continuously maintained with a 38°C heat stimulator at specific sites in the body. Conclusion: Regional heat stimulation by moxibustion provides fundamental evidence for effective bradycardia response.

Biometric authentication such as face recognition and fingerprint recognition have been pervasive. However, there are many attacks against the biometric authentication. One of them is a "presentation attack" using artificial biometrics to break the authentication. Meanwhile, several approaches using photoplethysmogram (PPG) which can be recorded optically for authentication have been proposed. PPG-based authentication may be available in the near future, because PPG have fewer restrictions in measurement sites and postures than other biometrics, and smartwatches with PPG recording function have been pervasive. Therefore, the prediction of attacks against PPG-based authentication and countermeasures are required. We proposed a presentation attack using the advantage of PPG in performing measurements on various sites. The attack records PPG stealthily and utilizes it for identity spoofing. We investigated the feasibility of the attack and showed that the attack may occur. We investigate countermeasures using the unique information of the measurement sites against the attack.

Automatic and long-term monitoring of respiratory is in great demand for lung diseases. It gets required greater in these years due to COVID-19 pandemic to reduce medical staff fatigue for checking patient conditions frequently for long time. Kobayashi et al., in our team, developed a device measuring respiratory condition by quantizing the displacement between the 6th and 8th ribs. We introduce long short-term memory (LSTM) neural network to classify patient respiratory signals into the two states of normal and low-functional respirations. The signals were checked by a medical doctor manually for classified into the two states. In the process, they were transformed to frequency-domain spectra with complex-valued wavelet transform, and then quantized the respiratory wavelet spectra due to the large number of spectra patterns. After that, the LSTM learned and classified the processed respiratory signals. The experimental results showed the feasibility to detect the two states.

Previous studies have shown that time-dependent cardiorespiratory responses before and after the onset of dynamic exercise at various intensities depend on the relationship between exercise training and its exercise intensity. However, it is not clear when and to what extent such differences in training intensity for the development of short- and long-term physiological adaptations affect cardiorespiratory function during exercise. The subjects were 16 college student athletes who were divided into 95% and 80% intensity training groups. After HIT, maximal oxygen uptake increased significantly in both groups. After HIT, maximal heart rate during step exercise increased significantly only in the 95% training group after HIT after 6 weeks, and an increase in heart rate immediately after the start of exercise was observed after HIT. We concluded that HIT intensity-dependent adaptive changes in cardiorespiratory function during exercise appear mainly in the cardiovascular system after 6 weeks.

Flap ischemia and consecutive flap loss is an innate complication in reconstructive free flap surgery. With the development of machine learning, time series analysis based flap failure prediction has become possible. With the laser doppler flowmetry pocket device (PocketLDF) by JMS it has become possible to measure skin perfusion every second. In this trial skin perfusion in addition to blood pressure, pulse and respiratory rate were measured in 3 patients and flap failure prediction based on the Auto-Regressive Moving Average (ARMA) model and the Long Short Term Memory (LSTM) network was conducted.Accurate perfusion prediction with the ARMA model for stationary processes and with the LSTM network for non-stationary processes was possible. In comparison with real time observation by the attending doctor, the ARMA model was able to predict flap ischemia ahead of time.

Magnetoencephalography (MEG) is an essential tool for non-invasive focus localization of epilepsy patients. However, little is known about the clinical value of MEG sharp transients (STs) when epileptic spikes are not found. At our hospital, 53 patients underwent comprehensive presurgical evaluations including head MRI, video EEG monitoring and MEG within the last 5 years. 15 out of 53 patients had only MEG STs. ECDs of STs were clustered in 6 patients. In 3 of them, clusters overlapped with structural lesions. Some dipoles overlapped with structural lesion in 1 patient without ECD cluster. 4 patients with clustered ECD and 5 patients without ECD cluster underwent surgical resection of structural lesions and all became seizure free. MEG sharp transients are less specific and difficult to localize compared with spikes, but good prognosis can be achieved by integrating with specific findings from other modalities.

53 mood disorder patients (mean 39 years) with 8 or more points on the Hamilton Depression Rating Scale and 58 healthy subjects (mean 36 years) were measured RR intervals and accelerations with wearable heart rate sensors (myBeat WHS-1, Union Tool Co., Ltd.) from 15:00 to 3 consecutive days. The average of heart rate variability and activity magnitude during waking and sleeping time period estimated from the accelerations were calculated, and those of patients were compared with controls by Mann Whitney U test. Compared with the controls, the patients had shorter RR intervals during both time periods. In the sleep time, the patients had less HF as index of the parasympathetic nervous system than controls. And the patients activity was less than the controls during the waking time periods. It was suggested that heart rate variability and activity magnitude during sleep and waking time periods could be objective indicators of depression.

Due to the labor shortage at Long-Term Care Health Facilities, the number of fall accidents is increasing at night. Therefore, to make up for labor shortages and assist with operations, it is necessary to construct a monitoring system that can detect the getting up action of the people requiring nursing care. So, in this study, we proposed a monitoring system that can detect the getting up using the infrared camera. As a verification result, we found that by using the near-infrared reflective sheet, it became easy to detect and track the actions and the features of the actions could be obtained. In addition, we proposed an algorithm that is a novel and specific to the body movement that proceeds to bed fall.

Objective: We aimed to estimate the velocity vector of the wrist based on the human intracranial electroencephalography (iEEG) and to control a robot arm three-dimensionally.

Methods: An epilepsy patient with implanted intracranial electrodes participated in this study. IEEGs were recorded while the patient imitated simulated movement of a robot arm. Independent component analysis (ICA) and partial least squares regression (PLS) were used to extract components specifically distributed over the sensorimotor areas. These components were used to estimate the wrist velocity vector using support vector regression (SVR). The robot arm was three-dimensionally controlled based on the estimated velocity using ROS where inverse kinematics were implemented.

Results: We developed the system for real-time three-dimensional control of a robot arm by estimating the wrist velocity based on iEEG using ICA, PLS and SVR.

Conclusion: Three-dimensional velocity control based on iEEG, ICA, PLS and SVR is feasible for real-time control of a robot arm.

We developed a new three-way isometric system that was capable of detecting the motion of each leaflet simultaneously of an ePTFE pulmonary valve by using three high-speed cameras. In this study, we designed a measurement system with the hemispherical placement of multi-cameras for three-dimensional valve reconstruction to examine mechanical stress in each leaflet under the pulsatile flow condition. We validated Images objects with a random pattern of 0.8-mm-diameter dots to reconstruct the three-dimensional surfaces from each couple of stereo images. As a result, we confirmed the three-dimensional reconstruction accuracy of dynamic changes in each leaflet surface conformation by using this method.

The mechanism of chronic cancer pain has yet fully elucidated even though nearly 80% of cancer patients suffer from chronic pain. We investigated the difference in brain activities between painful and painless cancer patients from 103 FDG-PET brain images of the head-neck or esophageal cancer patients. Painful cancer patients showed enhanced activity in the bilateral amygdala, hippocampus, and pons, and inhibited activity in the precuneus and middle cingulate gyrus relative to the painless patients. The metabolic connectivity related to the above regions showed a significant relationship with brain regions associated with the default mode network (DMN) in the painful cancer patients, while no significant metabolic connectivity to the DMN regions was found in the painless patients. These results indicate that in cancer pain patients, chronic pain may increase limbic system activity and inhibit the DMN, leading to changes in the cognition of pain and visceral sensation.

[Background and purpose] We constructed and experimented with a magnetoencephalography (MEG) hyperscanning system. However, it is necessary to confirm the data recorded by different MEGs can be directly compared. Therefore, we stimulated the primary sensory cortices of the same subject with two MEGs, and estimated the source activities.[Method] 101 ch custom-type MEG (Elekta-Neuromag) and 306 ch MEG (Vectorview, Elekta-Neuromag) were used. Auditory, visual, and somatosensory stimulations were performed respectively. [Result and discussion] The primary sensory cortex of the stimulated senses were activated. There was a slight variation in activated positions between those estimated by the two MEGs (< 20 mm), but they were located in the same brain regions within the Desikan-Killiany atlas (Desikan et al., 2006). This result suggests that the estimation of the synchronization using two MEGs is acceptable.

The octave illusion is an auditory phenomenon that occurs when two tones with one-octave difference are simultaneously played to both ears repeatedly. This paper aimed to find the most efficient way to classify participants into illusion (ILL) and non-illusion (non-ILL) groups by comparing the amplitude of ASSR at the auditory cortex for the ILL and non-ILL groups using brain data recorded with magnetoencephalography (MEG) among machine learning and deep learning techniques. We used three methods: support vector machine, convolutional neural network, and ensembling neural network for executing data's features. Despite longer training time and less accurate classification results, which could be the result of hyperparameter choice, we believe that ensembling convolutional neural networks is the most efficient way for classification ILL and non-ILL data.

We conducted a dual Magnetoencephalography (MEG) experiment to investigate the cortical signature in establishing non-verbal communication. Fourteen dyads who know each other silently watched either a live or a prerecorded video of the partner's face, under MEG recording. They were instructed to answer whether the face they watched was live or prerecorded at the end of each 20 s period. The alpha wave activities in the right caudal middle frontal gyrus (rMFG) were more correlated between two brains when they watched live relative to prerecorded video. Within the prerecorded video condition, the correlation between these regions less occurred when the dyad both correctly determined the video as prerecorded relative to other response conditions. These results suggest that the alpha band correlation in the rMFG of two brains may contribute to the establishment of live face-to-face communication.

We have developed a technique on noninvasive measurement of brain function with magnetically biased field (MBF). In this technique, human brain signal is measured as the fluctuation of a transcranial static magnetic field emitted by a coil placed on the scalp. In our previous study, the validity of MBF has been confirmed by the measurement of somatosensory evoked signals. Fast somatosensory evoked signals have been observed at the localized region representing the primary somatosensory area. In the present study, we measured the visual evoked signals to confirm the validity of MBF. We observed visual evoked signals at the localized region on the scalp in the vicinity of the primary visual cortex at 250ms after the stimulus. The ability of MBF to measure the fast brain signals with high spatial resolution was verified by the measurement of the visual evoked signals.

Recently, optically pumped magnetometers (OPMs) have attracted much attention as magnetic sensors for magnetoencephalography (MEG). In general, MEG requires multi-channel simultaneous measurements to estimate the signal sources. In this study, a hybrid OPM using a 5 cm glass cell containing two kinds of alkali metal atoms, K and Rb, was used to simultaneously measure MEGs at ten locations inside the cell.In the event-related desynchronization (ERD) measurements, the subjects were opened and closed their eyes 100 times every 4 seconds, whereas in the auditory evoked field (AEF) measurements, the sound stimuli were presented to the left ear 200 times.We could observe ERD in most of channels, but could not detect AEF signals using the hybrid OPM. This is because the distance between the sensing locations and the scalp was about 3 cm, so that we will reduce the distance by redesigning heaters and change the insulation method as well.

The frequency characteristics of spontaneous rhythms and evoked steady-state responses resulting from the electrical activity of the cortical neurons and physiological rhythms such as respiration and heartbeat are related by an even frequency ratio. Furthermore, the frequency of the heartbeat is correlated with body mass index (BMI), suggesting that the rhythmic properties of the body, including the brain, may be harmonically and hierarchically organised by a common continuum based on the constraints of biological structure. In this study, we investigate the harmonic structure as a mechanism of biological rhythms using magnetoencephalographic (MEG) signals. MEG detects magnetic field components derived from neuronal activity as well as physiological muscle movements. Simultaneous detection of the biomagnetic signals (and noise) enables a unified verification at the individual level, which may have various applications such as optimization of the audiovisual environment according to the biological characteristics of the individuals.

The reduction of environmental magnetic noise is crucial for MEG measurement and has been realized by using reference sensors located in the MEG dewar. However, there was a concern that the reference sensors might detect the signal from the brain of the subject as well as the environmental noise. We propose to use the reference sensors located in another MEG dewar, which is less likely to detect the signal from the brain of the subjects. We examined the feasibility of this idea using the calibrated MEG phantom and obtained affirmative results.

Objective: To evaluate the usefulness of repeat magnetoencephalography (MEG) as the preoperative evaluation in patients with medial temporal lobe epilepsy (MTLE).

Methods: 82 patients (42 males; average age at surgery, 30.9 years old) with MTLE who underwent MEG as the preoperative evaluation were enrolled. The conclusion of MEG was defined as five grades (1. definitive MTLE, 2. suspected MTLE, 3. TLE, 4. laterality, 5. inconclusive).

Results: The numbers of MEG were one (n=42, 51.2%), two (n=31, 37.8%) and three (n=9, 11.0%). The first MEG resulted in definitive or suspected MTLE in 27 patients (32.9%) and inconclusive in 38 (46.3%). Second MEG (n=18, 45.0%) and third MEG (n=1, 11.1%) revealed definitive or suspected MTLE. The conclusions were upgraded by repeat MEG in 19 patients (47.5%). Finally, 40 patients (49.3%) were diagnosed as definitive or suspected MTLE and 50 patients (61.6%) as TLE.

Conclusion: Repeat MEG could improve diagnostic value.

AbstractWe present a case with left frontal lobe epilepsy with focal aware seizure with eyes and head version to the right. MRI suggested a focal cortical dysplasia (FCD) in the left pre-central sulcus. EEG showed no interictal spikes nor EEG change during habitual seizures. MEG detected interictal spikes without concurrent EEG spikes. Source of MEG spikes was estimated near the left frontal lesion. After resection of the left frontal lesion, the patient became seizure free. Histopathological diagnosis was FCD type II. In this case, MEG was helpful to construct a unitary hypothesis of the left frontal lobe epilepsy due to FCD.

Atypical somatosensory localization is often found in a case of focal cortical dysplasia (FCD). Here we report a 14-year-old female patient medically intractable epilepsy of right sensorimotor seizures and right hemiplegia. MRI revealed a peri-rolandic FCD in the left parietal lobe. Somatosensory evoked magnetic fields (SEFs) for posterior tibial nerve stimuli indicated normal somatotopy of the foot area. However, SEFs for the right median nerve indicated marked reduction of the early components. Equivalent current dipole of the first peak at around 25 ms was localized on the central sulcus. However, this hand area localization was adjacent to the foot area. After implantation of subdural electrodes, somatosensory evoked potentials for the right median nerve stimulus confirmed the abnormal somatotopy predicted by pre-operative SEFs.

Background: To analyze High frequency oscillations (HFO) of magnetoencephalography, we have developed gradient magnetic-oscillation topography (GMOT), which projects every sensor vertically onto the brain surface and displays the power for each frequency on the brain surface. Methods: The subjects were 11 patients with intractable epilepsy who underwent focal resection. There were 7 males and 4 females (mean 23.0 years). Postoperative pathological findings were Glioma in 7, Cavernous hemangioma in 2, Hippocampal sclerosis in 1, and Focal cortical dysplasia type II in 1. GMOTs were created to visualize the power of 200-330 Hz. Fast ripples (FR) are defined as power of 800 (fT/m)^2/Hz or higher. The 3-35 Hz waveform was also analyzed by ECD.Results: ECDs clustered near the lesion in 8/11. GMOT visualized FR near the lesion in 9/11.Conclusion: The results of HFO analysis by GMOT showed almost the same as the ECD method.

It has been reported that frequency analysis results (MF: mean frequency, etc.) of spontaneous magnetoencephalographic(MEG) activity are useful as one of the indexes for diagnosing brain functions such as dementia. They need to be stable so that the same results can be obtained in different situations. However, the results are easily distorted by interference signals. Therefore, in this study, we applied the DSSP(Dual Signal Subspace Projection) method to the spontaneous brain activity data recorded under various conditions with MEG, and investigated its effect. The MF value was improved by performing DSSP on the data containing the interference signal. It was confirmed that even if DSSP was applied to clean data, there was almost no change in the MF value compared to the case without DSSP, and the frequency spectrum of the alpha-wave band did not change. It was suggested that the disadvantages of applying DSSP are extremely small.

In this study, we verified the reproducibility of vascular network structure of liver and to quantitatively evaluate the deformation in entire or local organ according to the body posture and respiratory state. We used an echography (Philips EPIQ Elite) equipped with a 3D probe to acquire multiple ultrasonic volumes, which include portal vein and hepatic vein from middle stem to right lobe, in various positions and respiratory states for six subjects. Spatial registration between multiple vascular networks was performed to derive the mean distance between common bifurcations using various body postures and respiratory states. As the result, the mean distance between common bifurcations tended to be smaller in the same conditions than in a different condition. We also confirmed the significant variation by age of the subject. This study suggested the possibility of evaluating organ properties by structural analysis of three-dimensional vascular networks.

In this study, we aim to estimate the tip position of a thin catheter in the ultrasound volume, where microbubbles were dispersed from the tip of the catheter in the blood vessel to analyze the variation of the spacial distribution by using an optical flow method. In free water, microbubbles were ejected from the tip of the catheter to be imaged in 4D mode of echography. The optical flow was calculated by setting a threshold value of brightness to limit the calculation area to determine the mean direction vector and the center of the distribution. The tip position was estimated using the relationship between the spatial arrangement and deviation estimated from the ejection rate of microbubbles. Since the estimation error was sufficiently lower than the size of focal area produced by the two-dimensional array transducer, the proposed method has the possibility to bend an in vivo thin catheter.

In a previous paper (Akazawa, Adv Biomed Eng 2019), the author proposed a new Hill-type two-mode model of muscle comprising a sliding filament mode and stretch-evoked force enhancement mode (ST-mode). It is shown that firing rates of some motor units of human finger extensor muscle are slightly lower in static position control than in isometric contraction (Kanosue, Jpn J Physiol 1983). Recent study showed that human finger extensor muscles operate on the descending limb of force-length relation (Llewellyn, Nature 2008). Computer simulation was performed to reveal mechanisms underlying these behaviors (Akazawa. Adv Biomed Eng 2020); the stable finger position can be maintained owing to the spring-like property of motor units operating in ST-mode.

In aging societies, daily monitoring of health status of the elderly people becomes important for maintaining quality of life and preventing accidents. Many researches of monitoring health status for elderly people in limited areas have been done. For continuous health monitoring of elderly people freely moving in outdoor environments, it is necessary to use low power consumption and wide area wireless communication network system at low costs. Therefore, we propose to use LPWA which is a general term of standards for the low power consumption and wide area wireless network systems being developed in recent years. In this study, we select plurality kinds of information which is considered effective for monitoring health status of elderly people and examine the available capacity for sharing these pieces of information using LPWA wireless network.

In recent years, the number of patients with dementia has been on the rise. It's possible to recover from cognitive impairment by early treatment in the time of mild cognitive impairment, called MCI, which is the preliminary stage of dementia. It's important to detect signs of MCI at home. We investigated the method for detecting MCI using multiple daily behavioral information and focused on the acoustic, linguistic and semantic features. The linguistic features are "quantitative changes in conversational content" caused by the decline of cognitive functions. The acoustic features are "changes in speech style" caused by changes in linguistic features. The semantic features are used to extract "changes in semantic content" for deficits in short-term memory. We defined those features which are assumed to be detectable for MCI, and tried to detect in conversation. In this report, we describe some results of experiments and examine the validity for MCI screening.

Early detection of chronic kidney disease (CKD) promotes early intervention to prevent renal failure. Although recommended by a CKD guideline 2018, screening using dipstick urinalysis remains suboptimal. One obstacle is that patients may not be screened for urine abnormalities at a primary care clinic. This report proposes a low-cost, simple, and accurate system of dipstick urinalysis judgment with image analysis. We prepared four different concentration samples by diluting urine pool products with distilled water. We placed a urine dipstick on a color chart and then photographed it using a smartphone. To acquire color information from images, we developed an image-analyzing system and judged the dipstick of urine albumin. Results from the original and conventional systems were then compared. In conclusion, this system has the potential to be used for dipstick urinalysis judgment.

We have proposed a method of time-frequency analysis of shunt murmurs to assess vascular access (VA) function in terms of the normalized correlation coefficient R, representing temporal variation in the frequency domain, and the normalized duration time NDT, representing temporal variation in the time domain. In this study, We proceeded to investigate the relationship between the vascular resistance index, RI, and this method of VA function assessment, and then went on to a basic investigation to establish a VA function assessment method with an inspection accuracy equaling that of RI from variations in shunt murmurs. With the experimental system, the results obtained by measuring the RI while directing the ultrasonic probe over the TOUGHSiLON Gel tube corresponding to the brachial artery upstream of the anastomotic region also indicated that the relationship of the RI to shunt murmur can be effectively investigated experimentally.

Consideration of the effects of differences in chamber geometry has generally been absent from reports on standardization of hemodialysis circuits, even though blood coagulation tends to occur in the venous air-trap chamber of a hemodialysis circuit because of both exposure of blood to internal air and delay or stagnation of blood flow. Therefore, in this study, a theoretical investigation of the effects of venous air-trap chamber design parameters on coagulation occurrence was performed by applying computational fluid dynamics (CFD) analysis to venous air-trap chambers in four different combinations of blood inlets and filters. Results matched the findings from the PIV visualization of less flow stagnation in the horizontal inflow chamber with a filter, and thus confirmed that effective theoretical estimation of the design parameters of venous air-trap chambers can be obtained by CFD analysis.

A cylindrical region in "straight type" indwelling needles currently used for hemodialysis at clinical sites induces noncontinuous widening of the blood-flow channel in the region of the needle-hub connection. "High-flow type" indwelling needles with a funnel-shaped region have therefore been marketed in recent years. But few reports provide any experimental answers to issues such as the increase in blood removal flow rate provided by funnel-shaped as opposed to straight type and the difference in their suction pressure. In the present study, we investigated the difference between the actual flow rate and suction pressure of each type of indwelling needle at different set flow rates. Comparing these results, we confirmed that a high-flow type maintains a higher flow rate. And a high-flow type maintains a higher actual flow rate than a straight type with the same suction pressure.

We are focusing on quantitative elucidation of the effects of three factors (blood inflow mode, chamber length, and filtration filter geometry), as a basis for proposal and design of an ideal venous air trap chamber geometry for prevention of blood coagulation. In the past, casein micelle formation to simulate blood coagulation in the venous air trap chamber has been induced by adding vinegar to heated bovine milk, with observation for casein micelles captured in a filtration filter accompanying a moderate increase in the blood circuit pressure. Blood coagulation could not be closely simulated in that way, however, because the cone-type filters of venous air trap chambers compared with other mesh-type filters are characterized by larger mesh openings through which the formed casein micelles are forced downstream. In the present study, we therefore investigated the use of sodium caseinate in the simulation.

Monitoring blood removal failure, where blood flow rate decreases from a set value, is generally performed by visual pillow observation, but reports on standardization of blood circuits for dialysis have noted that blood tends to stagnate in the pillow, resulting in clots, and the emergence of some other means of monitoring would eliminate the need for pillow. Some 30% of blood circuits are currently sold with no pillow, and a new method of monitoring blood removal failure is needed. The possibility of monitoring blood removal failure by continuous measurement of blood circuit vibration due to backflow induced by blood removal failure was therefore investigated.

Measurement of the change in blood circuit vibration displacement amplitude at each blood removal pressure showed a proportional relationship between the pressure and the amplitude, thus indicating that blood removal failure can be detected by monitoring the displacement amplitude of blood circuit vibration.

One major cause of blood-removal failure is the occurrence of sticking to the blood vessel by the blood removal port of the tip of a double-lumen catheter (DLC), and various DLC modifications have been proposed for its prevention. We have performed experimental assessments of the effects of various DLC design parameters to prevent an indwelling DLC sticking to simulated biological blood vessels formed from porcine inferior vena cava, as indicated by changes in blood removal pressure. However, variability among individuals in vena cava internal diameter (ID) and vascular wall thickness impedes reproducibility. In the present study, we therefore constructed an assessment system with TOUGHSiLON Gel artificial blood vessels for high reproducibility of the occurrence of sticking to blood vessel and used it to compare the performance of four different commercial DLCs.

Cardioassist therapy may cause centrifugal pump abnormalities. This study, purpose is to detect abnormalities that occur during cardioassist therapy. As basic study, we measured the vibration of centrifugal pump head used in external cardioassist circulation circuit based on the method used for industrial equipment diagnosis. Pump heads of two pumps were used in construction of circulation circuits. Sensor was secured to pump head, rotational frequency was set in increments of 500 rpm, and water was circulated through circuit. Vibrational quantities were analyzed, and differences between two pump heads were examined. Mean values of the displacement quantities were calculated for pump heads and different rotational frequencies. Results showed an increase in vibration with increasing rotational frequency and a difference between mean value of pump head displacement. In further studies, we will investigate possibility of quantitative recognition of abnormalities by measuring vibration in a centrifugal pump head with a simulated abnormality.

The neural basis of social cognition and interaction in human was frequently explored using a neuroimaging technique such as functional magnetic resonance imaging. Recent brand-new neuroimaging technique focusing on the sharing information is the hyperscanning neuroimaging: recording two (or more) brains simultaneously during social interaction. In the present paper, we will introduce author's previous hyperscanning fMRI studies.

The management of the electromagnetic environment is very important for the safe operation of a wireless medical telemetry systems (WMTSs). For example, not only own frequency channel management but also invasion waves coming from other facilities or electromagnetic noise radiated from electrical devices such as LED lamps. The spectrum analyzer (SA) has been widely used in the investigation and evaluation of electromagnetic environments, including hospitals. In general, SA is an expensive, but frequency of usage is comparatively lower. Additionally, it is difficult to operate SA by medical staffs because of their skills. I propose two types of simple approach of electromagnetic environment measurement methods in hospitals; one is the simplified SA function that is often installed in WMTS receivers and the other is the SA formed by software-defined radio. In this study, I present summary of these approach and report evaluation results of measurement accuracy.

Training under a medical professional is crucial to learn myoelectric prosthesis operation successfully and efficiently. To compensate the limited training time, it is essential to minimize the time consumed for sensor adjustment. The object of this research is to develop an adjustment process for myoelectric signal to stably operate the prosthetic device with minimal frequency observation by medical professional, especially during the take-home training. Quality Engineering RT method is applied as a pattern-recognition-based sensitivity adjustment. The relation of RT method's sample data number and discrimination rate is investigated while observing dissimilarity's validation are efficient as expectation function of the discrimination rate. and by experiment. Myoelectric sensor signal form 5 subject's forearm was processed with 10, 30, 50 sample data. As result, discrimination rate did not have explicit increase/decrease trend to the sample data number and could not be explained by dissimilarity's validation, and differed by subjects.

We investigated a low-load stress measurement algorithm using tablets and verified its effectiveness. The subjects took the Kleperin test as a stressor, and before and after that, they were ordered to move their finger to unlock the pattern lock on the tablet screen. At the same time, their heart rates were measured. From the measurement results, a strong negative correlation was found between the speed of finger movement and the heart rate after taking the Kleperin test. This indicates that the speed of finger movement may reflect the activity of the sympathetic nerve. Next, we investigate the relative error (stability) of the finger. As a result, after taking the Kleperin test, the stability decreased in the stroke of moving right to left. This indicates that there may be a negative correlation between stability and stress. In the future, we plan to study more effective measurement and evaluation methods.

Human-computer interfaces have been researched and developed as a communication tool for people with severe physical disabilities. In particular, as an alternative to the conventional mouse and keyboard, input devices that estimate intentions from biomedical signals are investigated. In this study, we paid attention to facial surface electromyogram (EMG) and electrooculogram (EOG), and attempted to develop a pointing device. The direction of the pointer is estimated from the EMG signals associated with the mouth movement, and the decision operation is performed from the vertical EOG signal when the user blinks voluntarily. We proposed an electrode arrangement to measure EMGs and vertical EOG simultaneously with a wireless biomedical measurement device. We experimented to evaluate the accuracy of the pointer operation with our electrode arrangement. As a result, the subjects could control the pointer in eight directions appropriately. In addition, we investigated the threshold of the EOG to detect the blink correctly.

In recent years, Sarcopenia caused by loss of muscle mass has become a problem.We need to measure Muscle mass to diagnose sarcopenia.Sarcopenia can be measured by Bioelectrical Impedance Analysis (BIA) and Dual-energy X-ray Absorptiometry (DXA).However, these methods have the problem such as high cost and very large.To solve this problem, we are investigating the use of ultrasound imaging and multichannel surface electromyography (EMG).Multichannel surface EMG can be acquired with a row of electrodes.This EMG provides a propagating wave that shows detailed information about the muscles.Therefore, we thought that a new evaluation standard could be created from multichannel surface EMG and ultrasound images.We compared propagating waves with ultrasound images.We confirmed that thick subcutaneous fat acquired fewer propagating waves and thick biceps had a faster propagation speed.The purpose of this study is to establish a new evaluation index for muscle.

Mismatch negativities (MMNs) for changes of melody-contours and pitch were measured in both musicians and non-musicians. Sequences of 5 tones with melody-contours of rising-falling/falling-rising/rising/falling shapes were used as standard stimuli, and five types of deviant were generated by changing pitch of the third note of each standard stimulus. As results, larger MMNs appeared for the melody-contour change in the musicians, whereas larger MMNs were observed for pitch change in the non-musicians. In term of effects of the melody-contour shape, variations of MMN amplitude depending on the deviant stimulus were larger in the rising-falling in the non-musicians, and both in the rising-falling and the falling-rising in musicians, respectively. In addition, the MMN latency was shorter for the musician than the non-musician. These results suggested that musical experience enhances the ability to perceive sound sequences as a group and consequently improves the discrimination of melody-contours, and increases the speed of melodic processing.

Most of the whole-head magnetoencephalograph systems detect the magnetic field radial to the head surface. The magnetic field distribution induced by the brain activity in the edge region of the helmet-shaped sensor array, for example, the activity of the visual cortex, can only be partially obtained, which deteriorates the accuracy of the magnetic field source estimation. We conducted a numerical experiment and found that the accuracy of the estimation of the magnetic source at the edge of the helmet can be improved by applying vector-type magnetometers that can detect not only the radial component but also the tangential components of the magnetic field at the edge of the sensor array.

The authors have developed a noise reduction signal processing method, named a mobile-reference sensor method, for biomagnetic measurement systems. In this study, we proposed employing a vibration meter (VM) and a fluxgate magnetometer (FGM) as reference sensors to detect the noise generated by the cryocooler installed near a magnetoencephalography (MEG).We placed an MEG cryostat and a helium-recycling system composed of a pulse tube cryocooler inside a magnetically shielded room and connected them by a transfer tube. We measured the vibration and the magnetic noise during operating the cryocooler using the MEG sensors, the VM and the FGM with various positions. The coherence values between the MEG sensors and the mobile reference sensors were maximized when the VM and FGM were put on the top and the side of the cryocooler, respectively. The obtained results suggested that the possibility to reduce the cryocooler-related magnetic noise from the recorded MEG data.