The background of our study is to apply advanced real-time gait analysis to walking interventions in daily-life setting. A vast of wearable devices provide gait information but not more than pedometer functions such as step counting, displacement and velocity. This paper suggests a real-time gait analysis method based on a head-worn inertial measurement unit (H-IMU). A novel analysis method implements real-time detection of gait events (heel strike, toe off, mid stance phase) and immediately provides detailed spatiotemporal parameters. The reliability of this method was proven by a measurement with over 11000 steps from seven participants on a 400 m outdoor track. The advanced gait analysis was conducted without any limitation of a fixed reference frame (e.g., indoor stage, infrared cameras). The mean absolute error in step-counting was 0.24%. Compared to a pedometer, additional gait parameters were obtained such as foot-ground contact time (CT) and contact time ratio (CTR). The gait monitoring system can be used as real-time and long-term feedback, which is applicable in the management of the health status and on injury prevention.

The pattern of gait after hip arthroplasty strongly affects regeneration and quality of life. Acoustic feedback could be a supportive method for patients to improve their walking ability and to regain a symmetric and steady gait. In this study, a new gait sonification method with two different modes—real-time feedback (RTF) and instructive model sequences (IMS)—is presented. The impact of the method on gait symmetry and steadiness of 20 hip arthroplasty patients was investigated. Patients were either assigned to a sonification group (SG) (n = 10) or a control group (CG) (n = 10). All of them performed 10 gait training sessions (TS) lasting 20 min, in which kinematic data were measured using an inertial sensor system. Results demonstrate converging step lengths of the affected and unaffected leg over time in SG compared with a nearly parallel development of both legs in CG. Within the SG, a higher variability of stride length and stride time was found during the RTF training mode in comparison to the IMS mode. Therefore, the presented dual mode method provides the potential to support gait rehabilitation as well as home-based gait training of orthopedic patients with various restrictions.

Gait symmetry analysis plays an important role in the diagnosis and rehabilitation of pathological gait. Recently, wearable devices have also been developed for simple gait analysis solutions. However, measurement in clinical settings can differ from gait in daily life, and simple wearable devices are restricted to a few parameters, providing one-sided trajectories of one arm or leg. Therefore, head-worn devices with sensors (e.g., earbuds) should be considered to analyze gait symmetry because the head sways towards the left and right side depending on steps. This paper proposed new visualization methods using head-worn sensors, able to facilitate gait symmetry analysis outside as well as inside. Data were collected with an inertial measurement unit (IMU) based motion capture system when twelve participants walked on the 400-m running track. From head trajectories on the transverse and frontal plane, three types of diagrams were displayed, and five concepts of parameters were measured for gait symmetry analysis. The mean absolute percentage error (MAPE) of step counting was lower than 0.65%, representing the reliability of measured parameters. The methods enable also left-right step recognition (MAPE ≤ 2.13%). This study can support maintenance and relearning of a balanced healthy gait in various areas with simple and easy-to-use devices.

The authors report the 60-GHz noise performance of low-noise ion-implanted In/sub x/Ga/sub 1-x/As MESFETs with 0.25 mu m T-shaped gates and amplifiers using these devices. The device noise figure was 2.8 dB with an associated gain of 5.6 dB at 60 GHz. A hybrid two-state amplifier using these ion-implanted In/sub x/Ga/sub 1-x/As MESFETs achieved a noise figure of 4.6 dB with an associated gain of 10.1 dB at 60 GHz. When this amplifier was biased at 100% I/sub dss/, it achieved 11.5-dB gain at 60 GHz. These results, achieved using low-cost ion-implantation techniques, are the best reported noise figures for ion-implanted MESFETs.<>