Toru Ifukube

An in-shoe device to measure plantar pressure during daily human activity

In this work, we report the development of a novel device, integrated into a shoe, to monitor plantar pressure under real-life conditions by reducing the spatial and temporal resolution. The device consists of a shoe insole with seven pressure-sensitive conductive rubber sensors and a wireless data transmission unit incorporated into a smaller measurement unit. One advantage of this approach is that the mass and volume of the measurement unit are less than 1/10th and 1/50th, respectively, of that reported for other devices. A comparison experiment was conducted for validation of the device using the F-scan system, and the initial test of the device was conducted by recording unobstructed gaits of one young adult subject and two elderly subjects. Each subject performed a straight, level walking trial at a comfortable speed for 7 m without any assistive device while wearing the in-shoe device. Changes in the plantar pressure during gait were recorded. Compared with the young subject, the pressure under the heel of the elderly subject was found to be smaller and less steep. This in-shoe device can be used to monitor plantar pressure during daily living and is expected to be useful in various clinical applications.

The Role of Toe-gap Force for the Evaluation of Falling Risk on the Elderly

This paper was proposed a toe-gap force measurement to estimate the lower limb muscular power. In the proposed method, the clipping toe-gap force is measured between the great toe and the digitus secundus. The toe-gap force in this situation, is muscles of the lower limb, which are supposed to have roles in the effort against falling. This study was used three experiments to determine whether or not the use of the toe-gap force measurement was useful from a practical viewpoint. First, the aging change in toe-gap force was examined by using the developed measuring device for 361 people included the elderly with physical weakness. Second, to examine the relation between the toe-gap force and falling, we were examined falling experience in a year for 82 healthy volunteers. Third, to examine the relation between muscular power and the toe-gap force, the results of the toe-gap force were compared to the result of the 10 m walking time for 153 healthy volunteers. We found following results: 1. the toe-gap force reflected the lower limb muscular power decrease rapidly from 65 years old. 2. The non-faller group demonstrated the factor of 1.3 greater toe-gap force compared with the faller group. The subjects who have less toe-gap force have experienced many falls. 3. the measured toe-gap force is closely related negative correlation to walking ability. This implies that the lower limb muscular power is reflected on the toe-gap force measurement. It is thus concluded that, the proposed method can be a practically useful method for evaluating quantitatively the lower limb muscular power of the elderly against fall.

Effects of Foot Arch Structure on Postural Stability

Background: In many human postural studies, the foot is considered to be a rigid body. The human foot is composed of the arch structure, which is characteristic in every person and deforms with aging. Foot arch structure is assumed to effect postural control; however, underlying mechanisms remain unclear. The aim of this study was to elucidate the relationship between the structure of the foot arch and postural control in the elderly. Methods: [Protocol 1] Thirty-seven healthy subjects participated in a test to determine the relationship between midfoot plantar pressure and arch height. Midfoot plantar pressure distribution (ratio of MP) was measured using the Shoe Type Stabilometer. The arch height was measured using a three-dimensional foot scanner. [Protocol 2] Ratio of MP and postural stability was measured in 143 elderly subjects using the Shoe Type Stabilometer. Postural stability was evaluated by center of pressure (CoP). Results: In Protocol 1, the correlation coefficient between the ratio of MP and ratio of arch height was r=−0.59 for the left foot and r=−0.54 for the right foot. Therefore, arch height could be predicted by ratio of MP. In Protocol 2, a significant correlation was recognized between the ratio of MP and lower limb strength, CoP total length, area anterior-posterior length, and medial-lateral (ML) length. Conclusions: The Shoe Type Stabilometer could evaluate CoP and foot arch structure. Using this device, it was found that people with a high ratio of MP, who tends to be flat-foot, displayed an increase in CoP sway. Therefore, foot arch structure contributed to postural control. Correlation between the ratio of MP and ML length, and between the ratio of MP and lower limb strength, indicated that the function of the plantar intrinsic foot muscles, which contributes to foot arch structure.

Development of System for Managing Individual Surgical Instruments by RFID

Among medical errors, surgery provides environments that are particularly vulnerable to malpractice and in which a single case of such malpractice could create a threat to the life of a patient. In this study, with the aim of implementing individual data management of surgical instruments using RFID tag, we developed a RFID tag that can be attached to surgical instruments. On clinical site, in order to implement individual management for surgical instruments, we focused on repeating sterilization characteristics, Durability and contamination tests during washing processes at medical site, impact resistance against falls.