Automatic Body Segment and Side Recognition of an Inertial Measurement Unit Sensor during Gait.

Inertial measurement unit (IMU) sensors are widely used for motion analysis in sports and rehabilitation. The attachment of IMU sensors to predefined body segments and sides (left/right) is complex, time-consuming, and error-prone. Methods for solving the IMU-2-segment (I2S) pairing work properly only for a limited range of gait speeds or require a similar sensor configuration. Our goal was to propose an algorithm that works over a wide range of gait speeds with different sensor configurations while being robust to footwear type and generalizable to pathologic gait patterns. Eight IMU sensors were attached to both feet, shanks, thighs, sacrum, and trunk, and 12 healthy subjects (training dataset) and 22 patients (test dataset) with medial compartment knee osteoarthritis walked at different speeds with/without insole. First, the mean stride time was estimated and IMU signals were scaled. Using a decision tree, the body segment was recognized, followed by the side of the lower limb sensor. The accuracy and precision of the whole algorithm were 99.7% and 99.0%, respectively, for gait speeds ranging from 0.5 to 2.2 m/s. In conclusion, the proposed algorithm was robust to gait speed and footwear type and can be widely used for different sensor configurations.

The effects of balance board on the balance parameters in five children with spastic cerebral palsy.

PURPOSE: This study evaluated the effects of an instrumented balance board on the balance parameters in children with spastic cerebral palsy by carrying out a pilot single-group pre-post clinical trial. METHODS: Five children aged 5 to 15 years with spastic diplegia and a Gross Motor Function Classification System level of I or II were included. All participants attended 20 sessions with an instrumented balance board, 45 minutes per session, 3 times a week for 7 weeks. The main outcome measures included the center of pressure excursion, velocity, and overshoot during quiet standing with open and closed eyes. The assessments were performed in the mediolateral and anteroposterior directions at pre- and one week post-intervention. RESULTS: Non-parametric tests showed that the excursion did not change significantly except in the mediolateral direction with eyes closed (p < 0.05). The velocity of the center of pressure improved in both directions and eye conditions (p < 0.05). Also, the maximum velocity decreased with eyes open (mediolateral, anteroposterior, and total) (p < 0.05), while the change was not significant with the eyes closed. The overshoot measurements did not change significantly. CONCLUSION: It is recommended to consider balance board training for improving balance parameters in children with cerebral palsy.

Knee adduction moment decomposition: Toward better clinical decision-making.

Knee adduction moment (KAM) is correlated with the progression of medial knee osteoarthritis (OA). Although a generic gait modification can reduce the KAM in some patients, it may have a reverse effect on other patients. We proposed the "decomposed ground reaction vector" (dGRV) model to 1) distinguish between the components of the KAM and their contribution to the first and second peaks and KAM impulse and 2) examine how medial knee OA, gait speed, and a brace influence these components. Using inverse dynamics as the reference, we calculated the KAM of 12 healthy participants and 12 patients with varus deformity and medial knee OA walking with/without a brace and at three speeds. The dGRV model divided the KAM into four components defined by the ground reaction force (GRF) and associated lever arms described with biomechanical factors related to gait modifications. The dGRV model predicted the KAM profile with a coefficient of multiple correlations of 0.98 ± 0.01. The main cause of increased KAM in the medial knee OA group, the second component (generated by the vertical GRF and mediolateral distance between the knee and ankle joint centers), was decreased by the brace in the healthy group. The first peak increased, and KAM impulse decreased with increasing velocity in both groups, while no significant change was observed in the second peak. The four-component dGRV model successfully estimated the KAM in all tested conditions. It explains why similar gait modifications produce different KAM reductions in subjects. Thus, more personalized gait rehabilitation, targeting elevated components, can be considered.

Comparing Two Orthoses for Managing Medial Knee Osteoarthritis: Lateral Wedge with Subtalar Strap While Barefoot Versus Lateral Wedged Insole Fitted Within Sandal.

BACKGROUND: Using foot orthoses for managing medial knee osteoarthritis (MKOA) is common, although its effectiveness is in debate. Most orthoses are placed inside the shoe as a lateral wedged insole. Thus, most studies in this area have focused on the effect of insoles used with shoes. This study compared the effects of a lateral wedge with subtalar strap (combined insole) used while barefoot and lateral wedged insole fitted within sandal on pain, function and external knee adduction moment (EKAM) in patients with MKOA to consider which orthotic treatment is better. METHODS: In this quasi-experimental pretest-posttest study, 29 participants with medial knee osteoarthritis were divided into two groups: (1) combined insole (n = 15) and (2) sandal (n = 14) groups. We recorded their gait while walking with and without orthoses using a motion analysis system. We evaluated their pain and performance with visual analog scale, Western Ontario and McMaster Universities Arthritis Index (WOMAC) questionnaire, 30 s chair stand, and Timed Up and Go functional tests. The pain and performance evaluations were repeated after one month. RESULTS: The pain immediately decreased after walking with both orthoses (p < 0.001). There was no significant difference in EKAM results between the two orthoses. Pain and performance improved in both groups after a one month using the orthoses (p < 0.01). CONCLUSION: Both types of orthoses have similar effect and lead to better performance and less pain after 1 month.

The association between motor modules and movement primitives of gait: A muscle and kinematic synergy study.

In spite of the extensive literature on the analysis of the muscle synergies during gait, the functionality of these synergies has not been studied in detail. This study explored the relationship between the motor modules and the kinematic maneuvers involved in human walking. Motion and surface electromyography data (of 28 trunk and lower extremity muscles) were acquired from ten healthy subjects during ten trials of self-selected speed gait each. The joint angle trajectories were half-wave rectified and divided into two independent positive directional degrees-of-freedom. The muscle and kinematic synergies were both extracted using the non-negative matrix factorization (NNMF) technique and clustered via k-means method. Results indicated that for both the muscle and kinematic synergies, a same number of modules (five) could reconstruct the 200 limb-trial data reasonably well. Moreover, each individual muscle synergy was found to be associated with a single kinematic synergy, based on the similar activation periods of the paired muscle and kinematic modules and the high correlation of their activation patterns (r = 0.88 ± 0.05), with a consistent phase advance for muscle synergies (mean = 7.59 ± 2.34 %). It was concluded that there is a one-to-one association between the motor modules and kinematic synergies, suggesting that each individual kinematic synergy, representing a movement primitive of human walking, might be implemented by recruitment of a paired motor module.

The effects of ankle-foot orthoses with plantar flexion stop and plantar flexion resistance using rocker-sole shoes on stroke gait: A randomized-controlled trial.

OBJECTIVES: This study aims to evaluate the effect of two ankle-foot orthoses (AFOs), AFO with plantar flexion stop (AFO-PlfS), and AFO with plantar flexion resistance (AFO-PlfR), while wearing standard shoes and rocker-sole shoes. PATIENTS AND METHODS: Between November 2017 and July 2018, in this randomized-controlled study, a total of 20 stroke patients (8 males, 12 females; mean age: 48.1 years; range, 33 to 65 years) in chronic phase were randomized to AFO groups (AFO-PlfS group, n=10 and AFO-PlfR group, n=10). Each group received the allocated AFO along with two kinds of shoes (standard shoe and rocker shoe) for a two-week adaptation. Two effects were separately evaluated: The orthotic effect and rocker shoe effect were defined as the evaluation of using an AFO wearing standard shoe compared to only standard shoe, and evaluation of using an AFO wearing rocker shoe compared to an AFO wearing standard shoe, respectively. The gait of each group was measured by three-dimensional motion analysis. RESULTS: A significant orthotic effect was found in both AFO groups in spatiotemporal parameters and maximum ankle dorsiflexion in the single-support phase. Additionally, the AFO-PlfR group showed a significant improvement in the parameters related to the first rocker of gait, but not for AFO-PlfS group concerning the orthotic effect. The rocker shoe effect was found in significant reduction of peak ankle plantar flexor moment and power ankle generation during preswing for both AFO groups. CONCLUSION: According to the orthotic effect, an AFO-PlfR can create better function in the improvement of parameters related to the first rocker. Although a rocker shoe can facilitate rollover for weight progression in the third rocker of gait, it cannot make a strong push-off function in stroke survivors.

Automatic classification of gait patterns in children with cerebral palsy using fuzzy clustering method.

BACKGROUND: Subjective classification of gait pattern in children with cerebral palsy depends on the assessor's experience, while mathematical methods produce virtual groups with no clinical interpretation. METHODS: In a retrospective study, gait data from 66 children (132 limbs) with a mean age of 9.6 (SD 3.7) years with cerebral palsy and no history of surgery or botulinum toxin injection were reviewed. The gait pattern of each limb was classified in four groups according to Rodda using three methods: 1) a team of experts subjectively assigning a gait pattern, 2) using the plantarflexor-knee extension couple index introduced by Sangeux et al., and 3) employing a fuzzy algorithm to translate the experiences of experts into objective rules and execute a clustering tool. To define fuzzy repeated-measures, 75% of the members in each group were used, and the remaining were used for validation. Eight parameters were objectively extracted from kinematic data for each group and compared using repeated measure ANOVA and post-hoc analysis was performed. Finally, the results of the clustering of the latter two methods were compared to the subjective method. FINDINGS: The plantarflexor-knee extension couple index achieved 86% accuracy while the fuzzy system yielded a 98% accuracy. The most substantial errors occurred between jump and apparent in both methods. INTERPRETATION: The presented method is a fast, reliable, and objective fuzzy clustering system to classify gait patterns in cerebral palsy, which produces clinically-relevant results. It can provide a universal common language for researchers.

Kinematic and electromyography analysis of paraplegic gait with the assistance of mechanical orthosis and walker.

Objective: To investigate the kinematics, functional sub-tasks, and excitation levels of the trunk and upper extremity muscles of paraplegic subjects during walker-assisted locomotion. Design: Retrospective cross-sectional study. Setting: Gait analysis laboratory. Participants: Eight individuals with spinal cord injury at T12, lower extremity motor score less than 4, and capable of walking independently with the assistance of ankle-foot orthosis and walker. Main Outcome Measures: Kinematics of pelvis, trunk, shoulder and elbow; trajectory of center of mass; and electromyography (EMG) activity of trunk and upper extremity muscles during gait. Results: Four subtasks were characterized for each locomotion step, based on the kinetics and kinematics data: (1) balance adjustment, (2) walker propulsion, (3) leg raising, and (4) leg swing. The latter two involved large lateral maneuvres by the trunk and pelvis and appeared to be the most skill- and muscle activity-demanding subtasks. The main muscles contributing into these subtasks were the ipsilateral paraspinal and abdominal muscles, as well as the contralateral scapulothoracic and shoulder girdle muscles, with EMG intensities significantly higher than their minimum mean intensities (P < 0.05) and those of the contralateral side (P < 0.05). Conclusions: Our results provide more insight into the functional sub-tasks and muscular demands of walker-assisted paraplegic gait that can help to design appropriate muscle strengthening programs, as well as developing more effective gait orthoses.

Designing instrumented walker to measure upper-extremity's efforts: A case study.

The high prevalence of shoulder pain in using walkers in patients who have spinal cord injury (SCI). Also, the limited options available to economically measure grip forces in walkers, which drove the need to create one. This article describes a method to obtain upper-extremities' forces and moments in a person with SCI by designing an appropriate instrumented walker. First, since the commercial multidirectional loadcells are too expensive, custom loadcells are fabricated. Ultimately, a complete gait analysis by means of VICON motion analysis and using inverse dynamic method has been held to measure upper-extremities' efforts. The results for a person with SCI using a two-wheel walker in low and high heights and a basic walker show that there are higher shoulder and elbow flexion-extension moments and also higher shoulder forces in superior-inferior direction and higher elbow and wrist forces in anterior-posterior directions. The results are not much different in using two different types of walker. By using the proposed method, upper-extremities' forces and moments were obtained and the results were compared to each other in using two different walkers.

Coordinated activities of trunk and upper extremity muscles during walker-assisted paraplegic gait: A synergy study.

Individuals with spinal cord injury (SCI) at lower thoracic levels might walk independently with the aid of mechanical orthoses and walker by using their unimpaired trunk and upper extremity muscles (TUEM). The required motor skills and the associated subtasks of the paraplegic locomotion, however, have not been well understood yet. The purpose of this study was to investigate the coordination of the TUEM activities throughout the paraplegic gait cycle using synergy analysis. For eight paraplegic individuals (30.6 ±â€¯11.6 years; SCI level: T12), the kinematics data and the surface electromyography (EMG) signals of TUEM were recorded during 15 gait cycles. Non-negative matrix factorization method was used to extract muscle synergies from the EMG results, which were time normalized in association with four stages of each gait step. For each subject, the number, structures and activation profiles of the muscle synergies across different gait cycles were highly similar, resulting in three subject-specific templates of synergy structure and activation profile with mean intra-subject similarity scores of 0.94 ±â€¯0.02 (p < 0.037) and 0.90 ±â€¯0.06 (p < 0.001), respectively. Hierarchical clustering of the subject-specific templates revealed five representative templates for all subjects, among which, three that were in common for at least six subjects were considered as the characteristic synergies of paraplegic locomotion. The first and second characteristic synergies (inter-subject similarity scores >0.91, p < 0.037) composed mainly of the pectoralis major, latissimus dorsi, longissimus, iliocostalis quadratus lumborum, and the triceps, posterior deltoid and lower trapezius muscles, respectively, and were activated during the ipsilateral and the contralateral leg raising and swing stages. The third characteristic synergy, (inter-subject similarity scores >0.95, p < 0.02), contained mainly the abdominal and lumbopelvic muscles and was activated during the balance adjustment and walker propulsion stages of the gait cycle. These results provide more insight into the motor skills and the associated subtasks of the paraplegic locomotion.

Role and Significance of Trunk and Upper Extremity Muscles in Walker-Assisted Paraplegic Gait: A Case Study.

Background and Purpose: Understanding the role and significance of trunk and upper extremity muscles in paraplegic gait can help in designing more effective assistive devices for these patients and also provides valuable information for improving muscle strengthening programs. Methods: In a patient with a spinal cord injury (SCI) who could walk independently (rating scale of ambulatory capacity, 9) with the aid of bilateral ankle-foot orthosis and a walker, the kinematics, kinetics and electromyographic (EMG) activities of 16 muscles from the trunk and upper and lower extremities were recorded during gait. The onset, cessation, and duration of the EMG signal were associated with the 4 phases of each step, distinguished based on the kinematics results. Results: It was found that the reciprocating activation pattern of the quadratus lumborum, latissimus dorsi, pectoralis major, and lower trapezius is responsible for trunk extension during the balance adjustment phase, leg unload and foot clearance creation during the leg raising phase, and propulsion force generation during the leg swing phase. Conclusion: The continuous activation of the rectus abdominis and erector spinae within the gait cycle helps stabilize the thorax and acts in reverse, that is, fixes the proximal joint and moves the distal limb. The shoulder girdle muscles contribute to the leg's unloading and then smooth landing during leg raising and leg swing phases, respectively.

Design, construction, and evaluation of "sensor lock": an electromechanical stance control knee joint.

BACKGROUND AND AIM: Most currently-available stance control knee ankle foot orthoses (SCKAFOs) still need full knee extension to lock the knee joint, and they are still noisy, bulky, and heavy. Therefore, the aim of this study was to design, construct, and evaluate an original electromechanical SCKAFO knee joint that could feasibly solve these problems, and thus address the problems of current stance control knee joints with regards to their structure, function, cosmesis, and cost. METHOD: Ten able-bodied (AB) participants and two (knee ankle foot orthosis) KAFO users were recruited to participate in the study. A custom SCKAFO with the same set of components was constructed for each participant. Lower limb kinematics were captured using a 6-camera, video-based motion analysis system. RESULTS: For AB participants, significant differences were found between normal walking and walking with the SCKAFO for temporal-spatial parameters and between orthoses with two modes of knee joints in the healthy subjects. Walking with stance control mode produced greater walking speed and step length, greater knee flexion during swing, and less pelvic obliquity than walking with a locked knee, for both AB and KAFO users. CONCLUSIONS: The feasibility of this new knee joint with AB people was demonstrated. Implications for rehabilitation Stance control knee ankle foot orthoses (SCKAFOs) are designed to stop knee flexion in stance phase and provide free knee movement during swing phase of walking. Due to their high cost, size, excessive weight, and poor performance, few SCKAFO were optimal clinically and commercially. The feasibility of the new knee joint with able-bodied people and poliomyelitis subjects was demonstrated.

Fuzzy control of a hand rehabilitation robot to optimize the exercise speed in passive working mode.

The robotic rehabilitation devices can undertake the difficult physical therapy tasks and provide improved treatment procedures for post stroke patients. During passive working mode, the speed of the exercise needs to be controlled continuously by the robot to avoid excessive injurious torques. We designed a fuzzy controller for a hand rehabilitation robot to adjust the exercise speed by considering the wrist angle and joint resistive torque, measured continuously, and the patient's general condition, determined by the therapist. With a set of rules based on an expert therapist experience, the fuzzy system could adapt effectively to the neuromuscular conditions of the patient's paretic hand. Preliminary clinical tests revealed that the fuzzy controller produced a smooth motion with no sudden change of the speed that could cause pain and activate the muscle reflexive mechanism. This improves the recovery procedure and promotes the robot's performance for wide clinical usage.

Wrist-RoboHab: a robot for treatment and evaluation of brain injury patients.

This article, introduces a new haptic robot, wrist-RoboHab, for upper limb rehabilitation of post stroke, orthopedic and Parkinson patients., The robot is designed for hand movement therapy and could be used for both treatment and evaluation purposes in three operational states; forearm supination/pronation, wrist flexion/extension and ulnar/radial deviation. At first the mechanical design and control system are described. Then the results of a case study are demonstrated. Clinical results, showed an improvement in Fugle-Meyer, AROM, power and the biomechanical assessment of the spasticity in a chronic patient. Furthermore, it was approved that the robot can have a good interaction with both, patient and therapist.