In Japan, 28.6% of the people who require nursing care are subject to prolonged bedrest. In order to prevent prolonged bedrest and improve their Activities of Daily Living (ADL), rehabilitation that promotes maintaining balance in a standing posture and walking training are effective. Here, we focus on the motions required for standing up, which are prerequisites for maintaining balance and walking. Forward and backward bending occur when standing up from a sitting or supine position, and these motions are related to a person's weakness. Patients suffering from cerebrovascular disease were selected as subjects for our experiments. The maximum angular velocity of the upper part of the body during the standing-up motion was measured and compared with the Functional Independence Measure (FIM) determined qualitatively by nurses. The sigmoid function and third-order polynomial functions were employed as mathematical models to estimate the FIM, and they showed correlations of 0.81 and 0.83, respectively. This high correlation shows that one measurement (e.g., estimate of FIM) can be used to evaluate the motions. Evaluating the measurement of motions required to stand up can provide information on how to improve ADL.

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Due to long-term physical inactivity when confined to a wheelchair, people with motor paralysis in their lower legs are always at risk of developing secondary diseases in the paralysis area; for example, muscle atrophy, loss of bone mineral density, and hypo-circulation. These diseases occur easily, but are difficult to cure. Daily stretching exercises are generally considered to be the most effective measure for prevention. However, often is the case that patients don't exercise due to a lack of willpower. We have developed an everyday rehabilitation device for individuals with motor disorders. It is comprised of a pair of linear actuators that mount under the seat of a wheelchair and are connected to each footrest, and works to prevent secondary disease by passively stretching the ankle joints. By installing the device on the wheelchair, patients do not have to transfer to another machine, which encourages them to use the device more frequently. The device has two different exercise modes: a rhythmical planter/dorsiflexion movement and a stretch mode. In the former mode, the neutral position was set at 105 deg. The range of the rotation angle was between +/-6 and +/-12 deg. The flapping frequency was set at 0.7 Hz based on a normal gait. In this study, we investigated the physiological effect of the former mode in the motion range of +/-12 deg. Twelve persons with spinal cord injuries participated in the experiment, and the EMG and blood flow in the paralyzed muscles were recorded during 10 min of passive ankle motion. As a result, we found that passive ankle motion can induce rhythmical muscular activity and enhance the blood flow in the calf muscles. These results suggest that this device might be effective for the prevention of secondary diseases, or the facilitation of neuromuscular function and peripheral circulation in paralyzed lower limbs.

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In order to realize a novel handheld monitor for the sympathetic nervous system, we fabricated an analytical system for salivary amylase activity (sAMY) using a dry-chemistry system called a “Cocoro Meter.” The device to quantify sAMY using an activity rate method was completely automated. This method was made possible by the fabrication of a disposable test-strip equipped with built-in salivacollecting and reagent papers, and an automatic saliva transfer mechanism. Within a range of sAMY between 0-200 kU/l, the calibration curve for the monitor showed a coefficient of R²=0.988 and CV (coefficient of variation) of 10.2%. The reproducibility between devices was within 10%. Moreover, it was demonstrated that: (i) the quantitativity of the sample collected by the test-strip was sufficient, (ii) the sublingual area was suitable as the sampling site of the saliva, and (iii) 30 s was sufficient for saliva sampling. Considering all of these effects including the saliva sampling site, a 12.1% CV was obtained for this monitor. A total of 1 min was sufficient to analyze the sAMY. Thus, this study demonstrated that the monitor might be used as a good index for psychological research.

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Layered manufacturing (rapid prototyping) is a processing technique which creates a three-dimensional object of a complicated shape based on cross-section data sliced from three-dimensional data such as that produced using CAD (computer-aided design). In this study, we proposed a powder-layered manufacturing process, which is one technique for rapid prototyping, to produce the desired bone shape for a transplantation from a biomaterial powder. Formation was carried out using conventional inkjet-type equipment. In the experiment, we used orthopedic filling-paste powder (BIOPEX), of which the main component was alpha-tribasic calcium phosphate, as the forming material. To solidify the powder, we used a sodium chondroitin sulfate+dibasic sodium succinate anhydride aqueous solution—the solvent for mixing powder in clinics—as the binder liquid. The binder liquid was applied to the surface of the powder material using a bubble jet-type inkjet device. As a first trial, we formed difficult thin plate-shaped sample (0.1 mm to 1.0 mm in thickness) and circular hole samples (0.5 mm to 5.0 mm in diameter) to examine the formability of this technique for artificial bone. As a result, the shape of the sample was affected by the swelling ratio; in particular, the thickness and diameter dimensions were smaller. However, the powder was clearly fixed, showing that the formation of artificial bone is possible using this technique. The measured formation accuracy of the sample was about 0.6 mm, and the smallest diameter was about 2.0 mm. As the next trial, we formed an animal bone, creating a rabbit femur from CT image data. As a result, though there was a constraint due to powder discharge, an animal bone with an internal void was produced. These result suggest that powder-layered manufacturing can be used as a new forming technique for artificial bones.

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MR guided surgery is quite effective in realizing accurate and safe minimally invasive surgery (MIS). The combination of intra-operative MRI, surgical navigation system, and surgical robot should be of practical use in the field of MIS in the future. When we use flexible endoscope type robotic manipulator, the position and the orientation of the tip point of the flexible forceps should be navigated and controlled by a robotic manipulator. However, the conventional position sensor can not be used because of the strong magnetic field and the limited workspace. We propose a novel tracking method named extended active tracking (EAT), which is based on the active tracking algorithm. EAT can measure the position and the orientation of the tracking coils synchronically. The principle of EAT is three points measurement by three series inductance. We can calculate the orientation of three coils using the measured 3-D positions of coils. In this paper, three experiments was conducted to evaluate the basic performance of the EAT. First experiment is the flip angle adjustment for the reduction of background noise, which is caused by the proton around each inductance. The experimental results shown that the inductance positions could be clearly observed without background noise at 6-deg flip angle with NMR signal peaks. Second experiment is the reproducibility evaluation. The fluctuation of measurement position and orientation were less than 0.3 mm (SD) and 1.0 deg (SD) at various positions and orientations. And standard deviation of the distance between the inductances at various positions and orientations is less than resolution (0.78 mm). Third experiment is an accuracy evaluation. The position measurement accuracy was 0.39 mm (RMS) using an optical tracking device. The orientation measurement accuracy was 3.5 deg (RMS) when the tracking coil was rotated 30 degree. Evaluation result suggests that EAT is possible to be used inside a patient body with the required accuracy.

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