Walking Assistive Device Research Articles

Unilateral non-electric assistive walking device helps neurological patients to improve gait patterns

Unilateral non-electric assistive walking device helps neurological patients to improve gait patterns

Walking Strategies and Performance Evaluation for Human-Exoskeleton Systems under Admittance Control.

Lower-limb exoskeletons as walking assistive devices have been intensively investigated in recent decades. In these studies, intention detection and performance evaluation are important topics. In our previous studies, we proposed a disturbance observer (DOB)-based torque estimation algorithm and an admittance control law to shape the admittance of the human-exoskeleton system (HES) and comply with the user’s walking intention. These algorithms have been experimentally verified under the condition of no ground reaction force (GRF) in our previous studies. In this paper, we devised and integrated with the exoskeleton control system a sensing and communication module on each foot to measure and compensate for GRF. Rigorous theoretical analysis was performed and the sufficient conditions for the robust stability of the closed-loop system were derived. Then, we conducted level ground assistive walking repeatedly with different test subjects and exhaustive combinations of admittance parameters. In addition, we proposed two tractable and physically insightful performance indices called normalized energy consumption index (NECI) and walking distance in a fixed period of time to quantitatively evaluate the performance for different admittance parameters. We also compared the energy consumption for users walking with and without the exoskeleton. The results show that the proposed admittance control law reduces the energy consumption of the user during level ground walking.

Sensorized Tip for Monitoring People with Multiple Sclerosis that Require Assistive Devices for Walking.

Multiple Sclerosis (MS) is a neurological degenerative disease with high impact on our society. In order to mitigate its effects, proper rehabilitation therapy is mandatory, in which individualisation is a key factor. Technological solutions can provide the information required for this purpose, by monitoring patients and extracting relevant indicators. In this work, a novel Sensorized Tip is proposed for monitoring People with Multiple Sclerosis (PwMS) that require Assistive Devices for Walking (ADW) such as canes or crutches. The developed Sensorized Tip can be adapted to the personal ADW of each patient to reduce its impact, and provides sensor data while naturally walking in the everyday activities. This data that can be processed to obtain relevant indicators that helps assessing the status of the patient. Different from other approaches, a full validation of the proposed processing algorithms is carried out in this work, and a preliminary study-case is carried out with PwMS considering a set of indicators obtained from the Sensorized Tip’s processed data. Results of the preliminary study-case demonstrate the potential of the device to monitor and characterise patient status.

Short-term effect of a close-fitting type of walking assistive device on spinal cord reciprocal inhibition

One of the major problems with walking encountered by patients with spastic hemiplegia is diminished toe clearance due to spasticity of their leg muscles. To improve their walking, a specialized robot assist for ankle movements (RE-Gait) has been utilized. The present study examined the neurophysiological effects whether spinal cord reciprocal Ia inhibition (RI) in the leg was altered by using RE-Gait. Sixteen patients with a clinical diagnosis of stroke were divided into the two groups, RE-Gait walking group (Group R) and normal (controlled) walking group (Group C). In each group, they walked on a flat floor for 15 min with or without RE-Gait. The depression of soleus (Sol) H-reflexes conditioned by common peroneal nerve stimuli with the conditioning-test (C-T) intervals of 1, 2, 3, and 4 ms were assessed before and immediately after each walking session. After the intervention, the LSM (SE) of Sol H-reflex amplitude with 1, 2 and 3 ms C-T interval conditions were significantly decreased in group R (1 ms: 88.15 (4.60), 2 ms: 86.37 (4.60), 3 ms: 89.68 (4.62)) compared to group C (1 ms: 105.57 (4.56), 2 ms: 100.89 (4.58), 3 ms: 107.72 (4.58)) [1 ms: p = 0.012, 2 ms: p = 0.035, 3 ms: p = 0.011]. Walking assistive robot that targets ankle movements might be a new rehabilitation tool for regulating spinal cord excitability.

산업용 상지 웨어러블 로봇에 대한 정성적 사용성 평가 가이드라인 연구

Objective: This study is to identify the components and qualitative criteria for assessing the usability of wearable robots in industrial use. Background: Wearable robot technology is a state-of-the-art application of humanrobot interaction (HRI) but research on its usability from the users point of view is insufficient. It is necessary for the wearable robot industry to establish safety standards and usability assessment system for deploying the technology on a commercial scale. Method: Sets of user requirements were identified from previous researches regarding with analogous products including walking aids, assistive and wearable devices. Qualitative assessment criteria were developed on the basis of user requirements classified by usability components and the structure of wearable robots. Results: The usability of wearable robots needs to be evaluated by 6 components: wearability, effectiveness, learnability, efficiency, utility, and safety. Qualitative assessment criteria consisted of 38 questionnaires corresponding to the identified user requirements that belong to each component. Conclusion: The 6 components with 38 assessment criteria would be utilized as the basis for further development of the usability assessment standard. Application The assessment criteria provide ideas and checklists for designing wearable robots with good usability.

Abstract P269: Physical Activity Relative Intensity is Inversely Associated With Mortality in Older Women

Background: Aerobic capacity and efficiency of movement reduce with aging, and do so at an accelerated rate. Consequently, the relative intensity (effort) of a defined physical activity (PA) task is higher at older compared with younger ages. The magnitude of association for PA relative intensity with health outcomes in older adults is unknown, and is a research priority identified in the 2018 PA Guidelines for Americans. Methods and Results: We followed 5,756 women, ages 63-99 years, for all-cause mortality (369 deaths) during a median of 4.3 years. Self-rated relative intensity during usual daily PA was determined using the Borg 0-10 point scale at baseline. PA relative intensity categories were “nothing to very weak” (Borg 0-2; n=1052; referent group), “weak” (Borg 3; n=2854), “moderate to maximal” (Borg ≥4; n=1850), over which numbers of deaths and crude mortality rates (per 1000 person-years) were 118 (25.7), 170 (13.0), 81 (9.5), respectively. In Cox regression analysis controlling for age, race-ethnicity, education, smoking, alcohol, use of assistive walking device, sleep duration, self-rated health status, number of comorbidities and BMI, hazard ratios (95% CI) across the above exposure categories were 1.00 (ref), 0.69 (0.54, 0.89), and 0.72 (0.53, 0.98), trend P=.03. The significant inverse association was evident in older women ≥80 years (HR: 1.00, 0.60, 0.68, trend P=.01) but not in women <80 years (HR: 1.00, 1.26, 0.99, trend P=.88; interaction P=.58). Conclusions: Self-rated PA relative intensity is inversely associated with mortality in older ambulatory women, and may provide a simple approach in epidemiologic studies to characterizing the relevance that age-related changes in aerobic fitness and energetics of movement have on health outcomes.

Determining the Most Appropriate Assistive Walking Device Using the Inertial Measurement Unit-Based Gait Analysis System in Disabled Patients.

ObjectiveTo evaluate the gait pattern of patients with gait disturbances without consideration of defilades due to assistive devices. This study focuses on gait analysis using the inertial measurement unit (IMU) system, which can also be used to determine the most appropriate assistive device for patients with gait disturbances.MethodsRecords of 18 disabled patients who visited the Department of Rehabilitation from May 2018 to June 2018 were selected. Patients’ gait patterns were analyzed using the IMU system with different assistive devices to determine the most appropriate device depending on the patient’s condition. Evaluation was performed using two or more devices, and the appropriate device was selected by comparing the 14 parameters of gait evaluation. The device showing measurements nearer or the nearest to the normative value was selected for rehabilitation.ResultsThe result of the gait evaluation in all 18 patients was analyzed using the IMU system. According to the records, the patients were evaluated using various assistive devices without consideration of defilades. Moreover, this gait analysis was effective in determining the most appropriate device for each patient. Increased gait cycle time and swing phase and decreased stance phase were observed in devices requiring significant assistance.ConclusionThe IMU-based gait analysis system is beneficial in evaluating gait in clinical fields. Specifically, it is useful in evaluating patients with gait disturbances who require assistive devices. Furthermore, it allows the establishment of an evidence-based decision for the most appropriate assistive walking devices for patients with gait disturbances.

Detecting self-paced walking intention based on fNIRS technology for the development of BCI.

Since more and more elderly people suffer from lower extremity movement problems, it is of great social significance to assist persons with motor dysfunction to walk independently again and reduce the burden on caregivers. The self-paced walking intention, which could increase the ability of self-control on the start and stop of motion, was studied by applying brain-computer interface (BCI) technology, a novel research field. The cerebral hemoglobin signal, which was obtained from 30 subjects by applying functional near-infrared spectroscopy (fNIRS) technology, was processed to detect self-paced walking intention in this paper. Teager-Kaiser energy was extracted at each sampling point for five sub-bands (0.0095~0.021Hz, 0.021~0.052Hz, 0.052~0.145Hz, 0.145~0.6Hz, and 0.6~2.0Hz). Gradient boosting decision tree (GBDT) was then utilized to establish the detecting model in real-time. The proposed method had a good performance to detect the walking intention and passed the pseudo-online test with a true positive rate of 100% (80/80), a false positive rate of 2.91% (4822/165171), and a detection latency of 0.39 ± 1.06s. GBDT method had an area under the curve value of 0.944 and was 0.125 (p < 0.001) higher than linear discriminant analysis (LDA). The results reflected that it is feasible to decode self-paced walking intention by applying fNIRS technology. This study lays a foundation for applying fNIRS-based BCI technology to control walking assistive devices practically. Graphical abstract Graphical representation of the detecting process for pseudo-online test. The lower figure is a partial enlargement of the upper figure. In the lower figure, the blue line represents the probability of walking predicted by GBDT without smoothing and the orange-red line represents the smoothed probability. The dark-red ellipse shows the effect of the smoothing-threshold method.

A Between-Subject fNIRS-BCI Study on Detecting Self-Regulated Intention During Walking.

Most BCI (brain-computer interface) studies have focused on detecting motion intention from a resting state. However, the dynamic regulation of two motion states, which usually happens in real life, is rarely studied. Besides, popular within-subject methods also require an extensive and time-consuming learning stage when testing on a new subject. This paper proposed a method to discriminate dynamic gait- adjustment intention with strong adaptability for different subjects. Cerebral hemoglobin signals obtained from 30 subjects were studied to decode gait-adjustment intention. Cerebral hemoglobin information was recorded by using fNIRS (functional near infrared spectroscopy) technology. Mathematical morphology filtering was applied to remove zero drift and EWM (Entropy Weight Method) was used to calculate the average hemoglobin values over Regions of Interest (ROIs). The gradient boosting decision tree (GBDT) was utilized to detect the onset of self-regulated intention. A 2-layer-GA-SVM (Genetic Algorithm-Support Vector Machine) model based on stacking algorithm was further proposed to identify the four types of self-regulated intention (speed increase, speed reduction, step increase, and step reduction). It was found that GBDT had a good performance to detect the onset intention with an average AUC (Area Under Curve) of 0.894. The 2-layer-GA-SVM model boosted the average ACC (accuracy) of four types of intention from 70.6% to 84.4% ( p = 0.005 ) from the single GA-SVM model. Furthermore, the proposed method passed pseudo-online test with the average results as following: AUC = 0.883, TPR (True Positive Rate) = 97.5%, FPR (False Positive Rate) = 0.11%, and LAY (Detection Latency) = -0.52 ± 2.57 seconds for the recognition of gait-adjustment intention; ACC = 80% for the recognition of adjusted gait. The results indicate that it is feasible to decode dynamic gait-adjustment intentions from a motion state for different subjects based on fNIRS technology. It has a potential to realize the practical application of fNIRS-based brain-computer interface technology in controlling walking-assistive devices.

A Machine Learning Approach to Perform Physical Activity Classification Using a Sensorized Crutch Tip

In recent years, interest in monitoring Physical Activity (PA) has increased due to its positive effect on health. New technological devices have been proposed for this purpose, mainly focused on sports, which include Machine Learning algorithms to identify the type of PA being performed. However, PA monitoring can also provide data useful for assessing the recovery process of people with impaired lower-limbs. In this work, a Machine-Learning based Physical Activity classifier design procedure is proposed, which makes use of the data provided by a Sensorized Tip that can be adapted to different Assistive Devices for Walking (ADW) such as canes or crutches. The procedure is based on three main stages: 1) defining a wide set of potential features to perform the classification; 2) optimizing the number of features by a Random-Forest approach, detecting the most relevant ones to classify five relevant activities (walking at a normal pace, walking fast, standing still, going up stairs and going down stairs); 3) training the ML-based classifiers considering the optimized feature set. A comparative analysis is carried out to evaluate the proposed procedure, using three ML-based classifier (Support Vector Machines, K-Nearest Neighbour and Artificial Neural Networks), demonstrating that the proposed approach can provide very high success rates if proper feature selection is carried out. This work presents four relevant contributions to the PA monitoring area: 1) the approach is focused on people that require ADW, which are not considered in other approaches; 2) an analysis of the features to characterize gait in people that require ADW is carried out; 3) a design procedure to optimize the number of features using a Random-Forest approach is used, avoiding a typical “brute force” procedure; and 4) a comparative analysis is carried out to demonstrate the validity of the approach.

Open Hip Abductor Tendon Repair into a Bone Trough: Improved Outcomes for Hip Abductor Tendon Avulsion.

Background:Hip abductor tendon tears are a well-recognized entity that results in progressive lateral hip pain, weakness, and limping. These can occur in patients with native hips or in patients following total hip arthroplasty. However, treatment of these 2 distinct groups does not differ. We describe a new repair technique utilizing a longitudinal bone trough in the greater trochanter. We compare our results (focusing on gluteus medius tendon avulsions) and traditional repair with suture anchors or transosseous bone tunnels. Additionally, we propose a classification system that attempts to describe the different types of tears to guide treatment, as the current classification system is not helpful in defining pathology or guiding treatment. Our proposed classification will help to better describe tear types anatomically and thereby guide appropriate surgical interventions based on these types.Description:Abductor tears were classified, according to our system, as Type I when there was no gluteus medius avulsion from bone (with subtype A indicating a partial tear of the gluteus minimus or gluteus medius; B, a complete tear of the gluteus minimus; and C, a longitudinal tear of the gluteus medius) or Type II when there was a gluteus medius avulsion (with subtype A indicating an avulsion of <50% of the insertion into the greater trochanter, and B, an avulsion of ≥50% of the insertion). Repair into a bone trough involves (1) freeing up and mobilizing the tendon from overlying fascia, (2) placing 2 evenly spaced Krackow stitches in the tendon, (3) creating a bone trough using a burr in the midline of the greater trochanter, (4) creating bone tunnels out the lateral wall of the trough to pass sutures, and (5) passing sutures through the bone tunnels to allow inset of the tendon into the trough, and later tying the sutures over the lateral osseous bridge.Alternatives:Alternative treatment options include nonoperative and operative management. Nonoperative treatment choices include physical therapy, nonsteroidal anti-inflammatory drugs, and activity modification with assistive walking devices. Surgical alternatives include endoscopic or open direct soft-tissue repair, suture anchor repair, bone tunnel repair, graft jacket reconstruction, or gluteus maximus muscle transfer.Rationale:Because of discouraging outcomes experienced by us and others, a new technique (a greater trochanter longitudinal bone trough) was developed to improve surgical results. This technique, utilizing an abductor tendon repair into a bone trough, improved our surgical outcomes for abductor tendon avulsions. We found that outcomes after surgical treatment of abductor tendon tears without avulsion are superior to those after repairs of abductor tendon avulsions, which is an important distinction compared with previous literature on abductor tendon repairs.

A Control Method for Walking Assistive Device Considering Emotion and Body Condition

A Control Method for Walking Assistive Device Considering Emotion and Body Condition

The Benefits of a Honda Walking Assist Device for Day Service Users

The Benefits of a Honda Walking Assist Device for Day Service Users

Gait Training Using a Wearable Robotic Device for Non-Traumatic Spinal Cord Injury: A Case Report

Introduction:We aimed to report the clinical evaluation results of gait training with the Honda Walking Assist Device® (HWAT) in a patient with spinal cord injury (SCI).Patients and Methods:A 63-year-old male with SCI (grade D on the American Spinal Injury Association Impairment Scale) underwent 20 HWAT sessions over 4 weeks. The self-selected walking speed (SWS), mean step length, cadence, 6-minute walking test (6MWT), Walking Index for SCI score, SCI Functional Ambulation Inventory gait score, American Spinal Injury Association Impairment Scale grade, neurological level, upper and lower extremity motor scores, modified Ashworth Scale, Penn Spasm Frequency Scale, and Spinal Cord Independence Measure version III were measured on admission, at the start of HWAT, at 2 and 4 weeks post-HWAT, and at discharge. Three-dimensional kinematic gait analysis and electromyographic assessments were performed before and after HWAT.Results:The patient safely completed 20 HWAT sessions. We found improvements above the clinically meaningful difference in SWS and 6MWT as well as increased hip extension, ankle plantar- and dorsi-flexion range of motion and increased hip extensor, abductor, adductor, and ankle plantar flexor muscle activity.Discussion:The SWS improved more markedly during the HWAT intervention, exceeding the minimal clinically important difference (0.10 to 0.15 m/s) in walking speed for people with SCI until discharge. Moreover, the 6MWT results at 2 weeks after the start of HWAT exceeded the cutoff value (472.5 m) for community ambulation and remained at a similar value at discharge.Conclusion:The walking distance (6MWT) and the walking speed (SWS) both demonstrated clinically important improvements following 20 treatment sessions which included HWAT.

Posture compensation of a walking assistive device using zero-moment point to stabilize motions on stairs

Posture compensation of a walking assistive device using zero-moment point to stabilize motions on stairs

Walking Assist Device Control without Delay Based on Plantar Forces Prediction by IMU Sensors

Walking Assist Device Control without Delay Based on Plantar Forces Prediction by IMU Sensors

Unpowered Walking Assistance Device by Using Ingeniously a Gravitational Field

Unpowered Walking Assistance Device by Using Ingeniously a Gravitational Field

Study about Output Characteristics of Walking Assistance Device Considering Functional Relationship between Hip and Knee Joint Angles

Study about Output Characteristics of Walking Assistance Device Considering Functional Relationship between Hip and Knee Joint Angles

The immediate effect of the Honda Walking Assist Device on foot and ankle function in hemiplegic stroke patients.

[Purpose] We evaluated the reliability of the measurement function of the Honda Walking Assist Device and investigated the effect of the device on walking improvements, and foot and ankle function, in hemiplegic stroke patients. [Participants and Methods] We recruited 16 hemiplegic stroke patients who performed 10-meter walk tests, twice without assistance and once with device assistance. Based on the rate of change of velocity, we divided the participants into two groups and compared the walking parameters, the toe grip strength, the cross tests, and the maximum step width. Two examiners assessed the 10-meter walk test results, and the authors calculated the intraclass correlation coefficients for walking speed, stride length, cadence, flexion, extension, and scissor angles. [Results] The intraclass correlation coefficients were greater than 0.70 for all the walking parameters we measured. The device increased hip joint movement but did not alter the maximum walking speed of the stroke patients. The patients in the group with a greater change in velocity displayed lower toe grip strength and decreased maximum step width and used orthoses more commonly. [Conclusion] The walking measurement function of the device was reliable. The immediate effect of the device in stroke patients may be influenced by the level of paralysis and the presence of an orthosis.

Admittance Control of Powered Exoskeletons Based on Joint Torque Estimation

In recent years, exoskeletons have been widely accepted as rehabilitative and walking assistive devices for either healthy persons or patients with mobility impairment. Depending on mobility of the wearers, the control strategies for exoskeletons may differ significantly. This paper aims at developing an admittance control framework for exoskeletons to assist healthy persons in safer, faster, or more energy-efficient walking. A crucial step to accomplish assistive walking for healthy persons is to detect their intention. Direct sensing of the wearer's biological signals, such as electromyography (EMG) and electroencephalography (EEG), requires additional sensors, which increases the cost and makes it inconvenient for the wearer to put on and take off the exoskeleton. Instead, we propose to detect the wearer's intention by estimating the total torques applied from the wearer to the human-exoskeleton system based on the motor current and joint angles. Then the velocity commands to the joint motors are generated according to the estimated torque and a predefined mechanical admittance function of each joint. Consequently, the exoskeleton complies with the wearer's intention. Rigorous theoretical analysis is performed on robust stability of the closed-loop system. Then experiments are carried out to verify the accuracy and robustness of the proposed torque estimation algorithm. In addition, experimental data show that the wearer's gait can be shaped in a desired way by choosing an appropriate admittance function in the proposed admittance control loop.