Ambulatory Measurement of Ground Reaction Forces

The measurement of ground reaction forces is important in the biomechanical analysis of gait and other motor activities. It is the purpose of this study to show the feasibility of ambulatory measurement of ground reaction forces using two six degrees of freedom sensors mounted under the shoe. One sensor was mounted under the heel, the other under the forefoot, thus allowing normal gait with flexion of the foot during push-off. The measurement of the ground reaction force was evaluated in a healthy subject, who walked repeatedly over a force plate. The ground reaction force reconstructed from the instrumented shoe sensor signals corresponded well with the force plate measurements, the RMS difference between the moduli of both ground reaction force measurements was 18.4 /spl plusmn/ 3.1 N (2.3 /spl plusmn/ 0.4% of maximal vertical ground reaction force) over 12 evaluated trials. The RMS distance of the center of pressure estimates of both measurement systems after optimal alignment was 3.1 /spl plusmn/ 0.4 mm

A gate-array/multi-electrode device: circuit performance and interfacing

The Twente 128-fold 3-dimensional multi-micro electrode device for endoneural stimulation is controlled by a 4×4 mm CMOS gate array chip. The chip contains the electronic circuitry, i.e. eight 16-channel multiplexers, eight double current sources and six differential amplifiers. Control of the gate array circuitry by a PC is done by a PCI interface. We present (aspects of) the design and realization of the PCI interface, as well as the simulated and measured performance figures of the current sources and amplifier

Gait analysis using ultrasound and inertial sensors

Introduction and past research:\ud Inertial sensors are great for orientation estimation, but they cannot measure relative positions of human body segments directly. In previous work we used ultrasound to estimate distances between body segments [1]. In [2] we presented an easy to use system for gait analysis in clinical practice but also in-home situations. Ultrasound range estimates were fused with data from foot-mounted inertial sensors, using an extended Kalman filter, for 3D (relative) position and orientation estimation of the feet.\ud \ud Validation:\ud From estimated 3D positions we calculated step lengths and stride widths and compared this to an optical reference system for validation. Mean (±standard deviation) of absolute differences was 1.7 cm (±1.8 cm) for step lengths and 1.2 cm (±1.2 cm) for stride widths when comparing 54 walking trials of three healthy subjects.\ud \ud Clinical application:\ud Next, the system presented in [2] was used in the INTERACTION project, for measuring eight stroke subjects during a 10 m walk test [3]. Step lengths, stride widths and stance and swing times were compared with the Berg balance scale score. The first results showed a correlation between step lengths and Berg balance scale scores. To draw real conclusions, more patients and also different activities will be investigated next.\ud \ud Future work:\ud In future work we will extend the system with inertial sensors on the upperand lower legs and the pelvis, to be able to calculate a closed loop and improve the estimation of joint angles compared with systems containing only inertial sensors

Developing healthy food preferences in preschool children through taste exposure, sensory learning and nutrition education

Purpose of Review: The present review was undertaken in order to summarize and evaluate recent research investigating taste exposure, sensory learning, and nutrition education interventions for promoting vegetable intake in preschool children. Recent Findings: Overall, taste exposure interventions yielded the best outcomes for increasing vegetable intake in early childhood. Evidence from sensory learning strategies such as visual exposure and experiential learning also show some success. While nutrition education remains the most common approach used in preschool settings, additional elements are needed to strengthen the educational program for increasing vegetable intake. There is a substantial gap in the evidence base to promote vegetable intake in food fussy children. Summary: The present review reveals the relative importance of different intervention strategies for promoting vegetable intake. To strengthen intervention effects for improving vegetable intake in preschool children, future research could consider integrating taste exposure and sensory learning strategies with nutrition education within the preschool curriculum

Ambulatory measurement of ground reaction forces

The measurement of ground reaction forces is important in the biomechanical analysis of gait and other motor activities. Many applications require full ambulatory measurement of these forces, but this is not supported by current measurement systems. We propose the use of two six-degrees-of-freedom force and moment sensors under each shoe, which enables the ambulatory measurement of ground reaction forces and centers of pressure (CoP). The feasibility of this method is illustrated by experimental results in a healthy subject, using a force plate as a reference. The ground reaction forces and CoP recordings show good correspondence when they are evaluated for forces above 40 N and when it is simply assumed that the sensors are flat on the ground when they are loaded. The root mean square (rms) difference of the magnitude of the ground reaction force over 12 gait trials was 15/spl plusmn/2 N, corresponding to 1.9/spl plusmn/0.3% of the maximum ground reaction force magnitude. The rms difference of the horizontal component of the ground reaction force was 3/spl plusmn/2 N, corresponding to 0.4/spl plusmn/0.2% of the maximum ground reaction force magnitude and to 2/spl plusmn/1% of the maximum of the horizontal component of the ground reaction force. The rms distance between both CoP recordings is 2.9/spl plusmn/0.4 mm, corresponding to 1.1/spl plusmn/0.2% of the length of the shoe, when the trajectories are optimally aligned