H. Dejnabadi

Bio: H. Dejnabadi is an academic researcher from École Polytechnique. The author has contributed to research in topics: Gyroscope & Gait analysis. The author has an hindex of 2, co-authored 2 publications receiving 347 citations.

A new approach to accurate measurement of uniaxial joint angles based on a combination of accelerometers and gyroscopes

Abstract: A new method of measuring joint angle using a combination of accelerometers and gyroscopes is presented. The method proposes a minimal sensor configuration with one sensor module mounted on each segment. The model is based on estimating the acceleration of the joint center of rotation by placing a pair of virtual sensors on the adjacent segments at the center of rotation. In the proposed technique, joint angles are found without the need for integration, so absolute angles can be obtained which are free from any source of drift. The model considers anatomical aspects and is personalized for each subject prior to each measurement. The method was validated by measuring knee flexion-extension angles of eight subjects, walking at three different speeds, and comparing the results with a reference motion measurement system. The results are very close to those of the reference system presenting very small errors (rms=1.3, mean=0.2, SD=1.1 deg) and excellent correlation coefficients (0.997). The algorithm is able to provide joint angles in real-time, and ready for use in gait analysis. Technically, the system is portable, easily mountable, and can be used for long term monitoring without hindrance to natural activities.

Gait analysis and WOMAC are complementary in assessing functional outcome in total hip replacement

Abstract: Objective: To investigate the correlation between objective and subjective evaluation of patients with total hip replacement.Design: Prospective preliminary trial comparing the Western Ontario and McMaster University questionnaire (WOMAC) and gait analysis preoperatively and three months postoperatively.Setting: A German academic orthopaedic centre specializing in total hip replacement surgery.Subjects: Seventeen patients (median age 70 years) with hip osteoarthritis.Intervention: All patients had had a primary unilateral total hip replacement.Main measures: WOMAC questionnaire to assess self-perceived health status and gait analysis to determine objective gait parameters.Results: Performance of walking as well as subjective judgement of health status improved following surgery (gait speed P = 0.0222; stride length P = 0.038; stance phase ratio P = 0.0466; WOMAC P < 0.0001). However, the correlation between gait parameters and WOMAC was poor (r = -0.27 or less). Correlation between changes of walking para...

The use of wearable inertial motion sensors in human lower limb biomechanics studies: a systematic review.

Abstract: Wearable motion sensors consisting of accelerometers, gyroscopes and magnetic sensors are readily available nowadays. The small size and low production costs of motion sensors make them a very good tool for human motions analysis. However, data processing and accuracy of the collected data are important issues for research purposes. In this paper, we aim to review the literature related to usage of inertial sensors in human lower limb biomechanics studies. A systematic search was done in the following search engines: ISI Web of Knowledge, Medline, SportDiscus and IEEE Xplore. Thirty nine full papers and conference abstracts with related topics were included in this review. The type of sensor involved, data collection methods, study design, validation methods and its applications were reviewed.