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ABSTRACT: Background: The Hybrid Assistive Limb (HAL) is a rehabilitation device that utilizes the “interactive biofeedback” hypothesis to facilitate the motion of the device according to the user's motion intention and appropriate sensory input evoked by HAL-supported motion. HAL has been studied extensively for its potential to promote walking function in patients with spinal cord lesions, including spinal cord injury. Methods: We performed a narrative review of HAL rehabilitation for spinal cord lesions. Results: Several reports have shown the effectiveness of HAL rehabilitation in the recovery of walking ability in patients with gait disturbance caused by compressive myelopathy. Clinical studies have also demonstrated potential mechanisms of action leading to clinical findings, including normalization of cortical excitability, improvement of muscle synergy, attenuation of difficulties in voluntarily initiating joint movement, and gait coordination changes. Conclusions: However, further investigation with more sophisticated study designs is necessary to prove the true efficacy of HAL walking rehabilitation. HAL remains one of the most promising rehabilitation devices for promoting walking function in patients with spinal cord lesions.

Abstract Objective The Hybrid Assistive Limb (HAL) has recently been used to treat movement disorders. Although studies have shown its effectiveness for chronic myelopathy, the immediate effects of HAL gait training on lower limb function have not been clarified. We conducted HAL gait training and examined its immediate effects on a 69-year-old man with re-deterioration of myelopathy in the chronic phase after surgery for compression myelopathy. The HAL intervention was performed every 4 weeks for 10 total sessions. Immediately before and after each session, we analyzed the patient’s walking ability using the 10-m walk test. In the 4th HAL session, the gastrocnemius muscle activity was measured bilaterally using a synchronized motion capture-electromyogram system. Results The training effects became steady after the 2nd session. In sessions 2–10, the step length increased from 0.56 to 0.63 m (mean: 0.031 m) immediately after HAL training. The motion capture-electromyogram analyses showed that considerable amounts of gastrocnemius muscle activity were detected during the stance and swing phases before HAL training. During and immediately after HAL training, gastrocnemius activity during the swing phase was diminished. HAL gait training has an immediate effect for inducing a normal gait pattern with less spasticity in those with chronic myelopathy.

Decreased muscle strength often occurs after anterior cruciate ligament (ACL) reconstruction; this can include muscle atrophy, neuromuscular dysfunction, and reduced force generation efficiency. Hybrid assistive limb (HAL) technology, which integrates an interactive biofeedback system connecting the musculoskeletal system to the brain and spinal motor nerves, offers a potential intervention. Our study, conducted from March 2018 to August 2023 using knee HAL single-joint technology, was a prospective non-randomized controlled trial involving 27 patients who had undergone arthroscopic ACL reconstruction. They were split into two groups: HAL (18 patients) and control (nine patients). Beginning 18 weeks after their surgery, the HAL group participated in three weekly sessions of knee HAL-assisted exercises. Both the HAL and control groups underwent isokinetic muscle strength tests at postoperative weeks 17 and 21. Testing utilized an isokinetic dynamometer at 60°/s, 180°/s, and 300°/s. The Limb Symmetry Index (LSI) was employed to measure side-to-side differences. The HAL group showed significant LSI improvements in peak extension torque across all testing velocities and for peak flexion torque at 60°/s and 300°/s. The rate of change in LSI for peak flexion torque at 300°/s was significantly higher post-measurements (p = 0.036; effect size = 1.089). The change rate for LSI in peak extension torque at 300°/s and all peak flexion torques showed medium to large effect sizes in Cohen’s d. In conclusion, knee HAL single-joint training positively influenced muscle strength recovery and efficiency. The HAL training group exhibited superior muscle strength at various isokinetic testing velocities compared to the control group.

Stroke rehabilitation with mechanical assistance improves outcomes by facilitating repetition and relieving the care burden of therapy staff. Here, we tested the Medical Care Pit (MCP) walking assistance training device in the rehabilitation of eight acute stroke patients (median age 60.7 ± 16.3 years) who had recently suffered ischemic (three) or hemorrhagic (five) stroke (14.1 ± 6.5 days). Patients received standard rehabilitation approximately 5 days per week (weekdays only), plus MCP therapy twice a week, totaling four MCP sessions over 2 weeks. Fugl–Meyer Assessment-Lower Extremities (FMA-LE), Functional Ambulation Category (FAC), and other gait-associated parameters were measured. Over the 10.5 ± 1.6 days of therapy, MCP qualitatively assisted in gait analysis and real-time patient feedback while independent walking scores significantly improved (FAC 2.2 ± 0.8 to 3.1 ± 1.3, p = 0.020). FMA-LE scores also slightly improved but not to significance (p = 0.106). Objective burden on patients, as measured by modified Borg scale, was significantly improved (2.7 ± 1.6 to 2.0 ± 1.6, p = 0.014). In terms of questionnaires, anxiety scores for the physical therapist regarding gait training and falling with MCP significantly decreased (3.8 ± 2.3 to 1.0 ± 1.6; p = 0.027 and 3.1 ± 2.2 to 0.8 ± 1.3; p = 0.045) from the first to fourth sessions. Taken together, MCP, in addition to the usual rehabilitation program, was effective in gait rehabilitation for independent walking and relieved burdens on the patients. Such walking support systems may be an important part of acute stroke rehabilitation.

Background and Objectives: Although postoperative C5 palsy is a frequent complication of cervical spine surgery, no effective therapeutic rehabilitation approach has been established for postoperative C5 palsy. The purpose of this study was to find evidence confirming the effectiveness and feasibility of robotic Hybrid Assistive Limb (HAL) shoulder exercises for C5 palsy. Materials and Methods: In this before-after, uncontrolled case series clinical study, we performed a mean of 11.7 shoulder training sessions using a shoulder HAL immediately after the onset of C5 palsy in seven shoulders of six patients who developed postoperative C5 palsy and had difficulty raising their shoulder during the acute postoperative phase of cervical spine surgery. Shoulder HAL training was introduced as early as possible after evaluating the general condition of all inpatients who developed C5 palsy. Patients underwent shoulder abduction training using shoulder HAL on an inpatient and outpatient basis at 2-week or 1-month intervals. Adverse events associated with shoulder HAL training were investigated. The shoulder abduction angle and power without the shoulder HAL were evaluated before shoulder HAL usage, at every subsequent session, and upon completion of all sessions. Results: Severe adverse events due to shoulder HAL training were not reported. After completion of all shoulder HAL sessions, all patients showed improved shoulder elevation, while shoulder abduction angle and power improved over time. Conclusions: Shoulder elevation training with HAL in patients in the acute stage of postoperative C5 palsy has the potential to demonstrate improvement in shoulder joint function with a low risk of developing severe adverse events.

Muscle co-contraction can result in higher joint contact forces, compromising knee joint mobility for stability, thus leading to impaired lower extremity neuromuscular control, delayed return to sports, and increased incidence of secondary anterior cruciate ligament (ACL) injury post-ACL reconstruction. Hybrid assistive limb (HAL) training has the potential to correct impairment of antagonistic or synergistic muscle movement of the knee joint through bioelectric signal feedback from muscle signals with computer processing. We considered that HAL training would contribute to improve peak muscle torque through coordinating or decreasing higher levels of muscle co-contractions and reducing differences between hamstring and quadriceps muscle activity on electromyography (EMG). While playing handball, a 20-year-old female injured her ACL upon landing on one leg. Two months post-injury, she underwent arthroscopic, anatomic single-bundle ACL reconstruction with a semitendinosus tendon autograft. At a 4-month follow-up, she underwent knee HAL training, which was performed once a week for three sessions. EMG data were collected during the evaluations of pre- and post-HAL training. The average muscle amplitude was used to calculate the difference between vastus lateralis (VL) and semitendinosus (ST) muscles, and the muscle co-contraction index (CCI). The CCI reflects the simultaneous activation of antagonistic muscles, which is determined for knee extensor-flexor muscle pairs. Post-knee HAL training, the CCI of the lateral hamstring and quadriceps muscles during extension was lower than that during pre-HAL training in all sessions. However, no differences were found in the CCI for the medial hamstring and quadriceps muscles during extension and flexion pre- and post-knee HAL training. For post-knee HAL training, the difference between VL and ST EMG data during a closed-chain squat was lower than that during pre-HAL training in all sessions. Knee HAL training contributed to improved peak muscle torque through coordinating or decreasing higher levels of muscle co-contractions, and it reduced differences between hamstring and quadriceps muscle activity in the ACL reconstructed leg as depicted by EMG.

Shoulder elevation, defined here as arm raising, being essential for activities of daily living, dysfunctions represent a substantial burden in patients’ lives. Owing to the complexity of the shoulder joint, the tightly coordinated muscular activity is a fundamental component, and neuromuscular impairments have devastating effects. A single-joint shoulder type version of the Hybrid Assistive Limb (HAL) allowing motion assistance based on the intention of the user via myoelectric activation has recently been developed, and its safety was demonstrated for shoulder rehabilitation. Yet, little is known about the physiological effects of the device. This study aims to monitor the changes in muscle activity and motion during shoulder HAL rehabilitation in several patients suffering from shoulder elevation dysfunction from cervical radicular origin. 8 patients (6 males, 2 females, mean age 62.4 ± 9.3 years old) with weakness of the deltoid muscle resulting from a damage to the C5 nerve root underwent HAL-assisted rehabilitation. We combined surface electromyography and three-dimensional motion capture to record muscular activity and kinematics. All participants showed functional recovery, with improvements in their Manual Muscle Testing (MMT) scores and range of motion (ROM). During training, HAL decreased the activity of deltoid and trapezius, significantly more for the latter, as well as the coactivation of both muscles. We also report a reduction of the characteristic shrugging compensatory motion which is an obstacle to functional recovery. This reduction was notably demonstrated by a stronger reliance on the deltoid rather than the trapezius, indicating a muscle coordination tending toward a pattern similar to healthy individuals. Altogether, the results of the evaluation of motion and muscular changes hint toward a functional recovery in acute, and chronic shoulder impairments from cervical radicular origin following shoulder HAL rehabilitation training and provide information on the physiological effect of the device.

Peripheral nerve disorder of the lower extremities causes drop foot and disturbs the daily living activities of patients. The ankle joint hybrid assistive limb (HAL) provides voluntary ankle joint training using surface bioelectrical signals from the muscles of the lower extremities. We investigated the neurological effects of ankle joint HAL training in three patients. Sensory nerve action potentials (SNAPs) and compound muscle action potentials (CMAPs) were analyzed for the peroneal and tibial nerves prior to the first ankle joint HAL training session. Integrated surface electromyography EMG signals were recorded before and after the HAL training sessions to evaluate the effects of training for neuromuscular disorders. The patients were hospitalized to receive rehabilitation with HAL training for 2 weeks. The HAL training was performed daily with two 60 min sessions. All cases demonstrated severe neuromuscular impairment according to the result of the CMAP. All integrated EMG measurements of antagonistic muscle activities decreased after the ankle joint HAL training. The manual muscle testing (MMT) scores of each muscle were slightly increased after the HAL intervention for Case 2(tibialis anterior, from 2 to 2+; gastrocnemius muscles, from 2− to 2; extensor digitorum longus, and extensor hallucis longus, from 1 to 3). The MMT scores were also slightly increased except for gastrocnemius muscle for Case 3 (tibialis anterior, extensor digitorum longus, and extensor hallucis longus, from 2− to 2). These two patients demonstrated voluntary muscle contractions and nerve signals in the CMAP before the HAL training. Even though the amplitude of CMAPs was low, the HAL training may provide voluntary ankle joint movements by reducing the antagonistic muscle contraction via computer processing. The HAL training may enhance muscle movement and coordination through motor learning feedback.

Upper extremity dysfunction after stroke affects quality of life. Focusing on the shoulder joint, we investigated the safety and effectiveness of rehabilitation using a shoulder joint hybrid assistive limb (HAL). Eight patients with chronic stroke and upper extremity functional disability were enrolled and used a shoulder joint HAL, which assisted shoulder movement based on the user’s intention, through myoelectric activation of the shoulder flexor. Ten training sessions of 30–40 min each were performed to assist voluntary movement of upper limb elevation on the affected side through triggering the deltoid muscle. All patients completed the interventions without shoulder pain. Surface electromyography evaluation indicated post-intervention improvement in coordinated movement of the affected upper extremity. Significant improvements in voluntary and passive shoulder joint range of motion were obtained after the intervention, suggesting improvement in shoulder muscle strength. A significant decrease in the modified Ashworth scale and improvements in functional scores in the upper limb were also observed. Along with safe use for our study patients, the shoulder HAL provided appropriate motor learning benefits. Improvements in shoulder joint function and whole upper limb function were observed, suggesting that HAL could be an optimal treatment method.

Sensory ataxia due to posterior cord syndrome is a relevant, disabling condition in nontraumatic spinal cord dysfunction. Ataxic gait is a common symptom of sensory ataxia that restricts activities of daily living. A 70-year-old woman with severe sensory disturbance was diagnosed with intradural extramedullary spinal cord tumors found in the thoracic spine region (T8). Surgical management of the tumors was performed. The patient received gait training 20 days after surgery (postoperative acute phase) using a hybrid assistive limb (HAL). HAL is a wearable exoskeleton cyborg that provides real-time assistance to an individual for walking and limb movements through actuators mounted on the bilateral hip and knee joints. Walking ability was assessed using the 10 m walking test, which included evaluating walking speed, step length, and cadence in every session. To evaluate the immediate effects of HAL training, walking speed and step length were measured before and after the training in each session. During the 10 m walking test, gait kinematics and lower muscle activity were recorded using a motion capture system and wireless surface electromyography before the first session and after completion of all HAL sessions. After the HAL training sessions, improvement in the patient’s gait performance was observed in the gait joint angles and muscle activity of the lower limb. After 10 training sessions, we observed the following changes from baseline: walking speed (from 0.16 m/s to 0.3 m/s), step length (from 0.19 m to 0.37 m), and cadence (from 50.9 steps/min to 49.1 steps/min). The average standard deviations of the knee (from right, 7.31; left, 6.75; to right, 2.93; p < 0.01, left, 2.63; p < 0.01) and ankle joints (from right, 6.98; left, 5.40; to right, 2.39; p < 0.01, left, 2.18; p < 0.01) were significantly decreased. Additionally, walking speed and step length improved immediately after completing all the HAL training sessions. This suggests that HAL gait training might be a suitable physical rehabilitation program for patients with sensory ataxia causing dysfunctional movement of the lower limb.

C5 palsy is a serious complication that may occur after cervical spine surgery; however, standard procedures for shoulder rehabilitation for patients with postoperative C5 palsy have not yet been established. We used a wearable robot suit Hybrid Assistive Limb (HAL) in a patient with delayed recovery after postoperative C5 palsy and conducted shoulder abduction training with the HAL. A 62-year-old man presented with weakness in his left deltoid muscle 2 days after cervical spine surgery. He experienced great difficulty in elevating his left arm and was diagnosed with postoperative C5 palsy. Seven months after surgery, shoulder abduction training with a HAL was initiated. In total, 23 sessions of shoulder HAL rehabilitation were conducted until 26 months after surgery. His shoulder abduction angle and power improved at every HAL session, and he was able to fully elevate his arm without any compensatory movement after the 23rd session, suggesting that the HAL is a useful tool for shoulder rehabilitation in patients with postoperative C5 palsy. We employed shoulder HAL training for a patient with delayed recovery from postoperative C5 palsy and achieved complete restoration of shoulder function. We believe that the HAL-based training corrected the erroneous motion pattern of his paralyzed shoulder and promoted errorless motor learning for recovery. Our collective experience suggests that shoulder HAL training could be an effective therapeutic tool for patients with postoperative C5 palsy.

We hypothesized that gait treatment with a wearable cyborg Hybrid Assistive Limb (HAL) would improve the walking ability of patients with hemiparesis after stroke. This study aims to evaluate the efficacy and safety of gait treatment using HAL versus conventional gait training (CGT) in hemiplegic patients with acute stroke and establish a protocol for doctor-initiated clinical trials for acute stroke. We will enroll patients with acute stroke at the University of Tsukuba Hospital. This study is a single-center, randomized, parallel-group, controlled trial (HAL group, n = 20; control group, n = 20) that will include three phases: (1) pre-observation phase (patient enrollment, baseline assessment, and randomization); (2) treatment phase (nine sessions, twice or thrice per week over 3−4 weeks; the HAL and control groups will perform gait treatment using HAL or CGT, respectively, and finally (3) post-treatment evaluation phase. The Functional Ambulation Category score will be the primary outcome measure, and the following secondary outcome measures will be assessed: Mini-Mental State Examination, Brunnstrom recovery stage of lower limbs, Fugl–Meyer assessment of lower limbs, 6-min walking distance, comfortable gait speed, step length, cadence, Barthel Index, Functional Independence Measure, gait posture, motion analysis (muscle activity), amount of activity (evaluated using an activity meter), stroke-specific QOL, and modified Rankin Scale score. The baseline assessment, post-treatment evaluation, and follow-up assessment will evaluate the overall outcome measures; for other evaluations, physical function evaluation centered on walking will be performed exclusively, excluding ADL and QOL scores. This study is a randomized controlled trial that aims to clarify the efficacy and safety of gait treatment using HAL compared with CGT in hemiplegic patients with acute stroke. In addition, we aim to establish a protocol for doctor-initiated clinical trials for acute stroke based on the study results. If our results demonstrate the effectiveness of the proposed treatment regarding outcomes of patients with hemiplegic acute stroke, this study will promote the treatment of these patients using the HAL system as an effective tool in future stroke rehabilitation programs. The study protocol was registered with the Japan Registry of Clinical Trials on October 14, 2020 (jRCTs032200151).

Ossification of the posterior longitudinal ligament (OPLL) is a hyperostonic condition in which the posterior longitudinal ligament becomes thick and loses its flexibility, resulting in ectopic ossification and severe neurologic deficit (Matsunaga and Sakou, 2012). It commonly presents with myelopathy and radiculopathy and with myelopathy progression motor disorders and balance disorders can appear. Even after appropriate surgical decompression, some motor impairments often remain. The Hybrid Assistive Limb (HAL) is a wearable powered suit designed to assist and support the user's voluntary control of hip and knee joint motion by detecting bioelectric signals from the skin surface and force/pressure sensors in the shoes during movement. In the current study, the HAL intervention was applied to 15 patients diagnosed with OPLL who presented with myelopathy after decompression surgery (6 acute and 9 chronic stage). Following the HAL intervention, there were significant improvements in gait speed, cadence, stride length, in both acute and chronic groups. Joint angle analysis of the lower limbs showed that range of motion (ROM) of hip and knee joints in acute group, and also ROM of hip joint and toe-lift during swing in chronic group increased significantly. ROM of knee joint became closer to healthy gait in both groups. Electromyography analysis showed that hamstrings activity in the late swing phase increased significantly for acute patients. Immidiate effect from HAL session was also observed. EMG of vastus medialis were decreased except chronic 7th session and EMG of gastrocnemius were decreased except acute 7th session, which suggests the patients were learning to walk with lesser knee-hypertension during the sessions. After all, double knee action appeared in both acute and chronic groups after the HAL intervention, rather than knee hyper-extension which is a common gait impairment in OPLL. We consider that these improvements lead to a smoother and healthier gait motion.

Foot and ankle disabilities (foot drop) due to common peroneal nerve palsy and stroke negatively affect patients’ ambulation and activities of daily living. We developed a novel robotics ankle hybrid assistive limb (HAL) for patients with foot drop due to common peroneal nerve palsy or stroke. The ankle HAL is a wearable exoskeleton-type robot that is used to train plantar and dorsiflexion and for voluntary assistive training of the ankle joint of patients with palsy using an actuator, which is placed on the lateral side of the ankle joint and detects bioelectrical signals from the tibialis anterior (TA) and gastrocnemius muscles. Voluntary ankle dorsiflexion training using the new ankle HAL was implemented in a patient with foot drop due to peroneal nerve palsy after lumbar surgery. The time required for ankle HAL training (from wearing to the end of training) was approximately 30 min per session. The muscle activities of the TA on the right were lower than those on the left before and after ankle HAL training. The electromyographic wave of muscle activities of the TA on the right was slightly clearer than that before ankle HAL training in the resting position immediately after ankle dorsiflexion. Voluntary ankle dorsiflexion training using the novel robotics ankle HAL was safe and had no adverse effect in a patient with foot drop due to peroneal nerve palsy.

Disorders of the central nervous system sometimes cause severe sensory motor paralysis accompanied by gait impairment. Recently, there are several reports on the effectiveness of robot-assisted gait training for patients experiencing these issues. The purpose of this case report was to assess the neuromechanical effect of a wearable robot suit HAL (Hybrid Assistive Limb) during post-operative gait training in a patient with gait impairment due to compressive myelopathy caused by ossification of the posterior longitudinal ligament (OPLL). For this purpose, we compared lower limb muscular activities while the patient was walking with and without the robot through a course of treatment sessions by (i) gait phase-dependent muscle usage analysis, (ii) muscle synergy analysis, and (iii) muscle network analysis. The results show (i) enhanced activity of the extensor muscles for weight-bearing in the initial sessions by using HAL and reduced knee extensor and increased hip extensor activations for achieving larger steps and faster gait in the later sessions; (ii) involvement of a greater number of synergies during walking with HAL than without HAL; and (iii) modulated muscle network property during walking with HAL remaining until the next HAL session. The patient's gait was improved after completing HAL sessions, acquiring close to normal joint profile with greater range of joint movement, faster walking speed, and larger step length. We discuss that the muscular activity modulation during walking with HAL suggests altered control of the muscles by the central nervous system during post-operative walking. Activity-dependent sensorimotor augmentation by HAL is discussed in the context of recovery of gait control by the central nervous system. The relationship between the altered control and the achieved gait recovery requires further investigation.

We hypothesized that a single-leg version of the Hybrid Assistive Limb (HAL) system could improve the gait and physical function of patients with hemiparesis following a stroke. In this pilot study, we therefore compared the efficacy of HAL-based gait training with that of conventional gait training (CGT) in patients with acute stroke. Patients admitted to the participating university hospital were assigned to the HAL group, whereas those admitted to outside teaching hospitals under the same rehabilitation program who did not use the HAL were assigned to the control group. Over 3 weeks, all participants completed nine 20 min sessions of gait training, using either HAL (i.e., the single-leg version of HAL on the paretic side) or conventional methods (i.e., walking aids and gait orthoses). Outcome measures were evaluated before and after the nine training sessions. The Functional Ambulation Category (FAC) was the primary outcome measure, but the following secondary outcome measures were also assessed: National Institutes of Health Stroke Scale, Fugl–Meyer Assessment (Lower Extremity), comfortable walking speed, step length, cadence, 6-min walk distance, Barthel Index, and Functional Independence Measure. In total, 22 post-stroke participants completed the clinical trial: 12 in the HAL group and 10 in the CGT group. No serious adverse events occurred in either group. The HAL group showed significant improvement in FAC after nine sessions when compared with the CGT group (P = 0.014). However, secondary outcomes did not differ significantly between the groups. Our results demonstrate that HAL-based gait therapy may improve independent walking in patients with acute stroke hemiplegia who are dependent on ambulatory assistance. A larger-scale randomized controlled trial is needed to clarify the effectiveness of single-leg HAL therapy.Clinical Trial Registration: UMIN Clinical Trials Registry, identifier UMIN000022410.

Abstract Background Maintenance or restoration of a good range of motion of the knee is one of the most important outcomes following knee surgery. According to previous studies, opening wedge high tibial osteotomy enables better recovery of range of motion in knee flexion than that achievable after total knee arthroplasty or unicompartmental knee arthroplasty. However, few reports provide a detailed description of the postoperative recovery of knee extension range of motion after opening wedge high tibial osteotomy. We describe our experience with a knee extension training program using a single-joint hybrid assistive limb device (HAL-SJ; Cyberdyne Inc., Tsukuba, Japan) during the acute recovery phase after opening wedge high tibial osteotomy. The HAL-SJ is a wearable robotic device that facilitates voluntary control of knee joint motion. Case presentation A 67-year-old Japanese woman who underwent opening wedge high tibial osteotomy for spontaneous osteonecrosis of the left medial femoral condyle received HAL-SJ-based knee extension training postoperatively. Our experience with this patient revealed that knee extension training with the HAL-SJ during the acute phase following opening wedge high tibial osteotomy is feasible. Furthermore, the patient’s knee extension range of motion improved to values similar to those seen during the preoperative stage, and her flexion range of motion was improved at 3 months after the surgery. Conclusions HAL-SJ-based knee extension training could be used as a novel post-opening wedge high tibial osteotomy rehabilitation modality. Further exploration of individualized optimal settings of the HAL-SJ is required to improve its safety and efficacy.

Cerebral palsy (CP) patients with spastic diplegia struggle to perform activities of daily life (ADL) using their upper arms. The single-joint-type Hybrid Assistive limb (HAL) for upper limbs is a new portable robot that can provide elbow motion support in accordance with bioelectric activation of patient's biceps and triceps brachii muscles. The purpose of this study is to assess the feasibility and efficacy of the use of HAL for CP patients. Two patients were enrolled in this study. (Case 1: a 19-years-old male, at the Gross Motor Function Classification System (GMFCS) level IV, Case 2: a 17-years-old male at GMFCS level III). Both these patients experienced difficulty in voluntary elbow extension in ADLs. The HAL intervention (eight sessions; voluntary extension-flexion training of the elbow with HAL and clinical evaluation) was conducted for both sides in Case 1 and for the right side in Case 2. Clinical assessments were conducted as follows: Surface electromyography was used to evaluate the muscle activities of the biceps, triceps brachii, trapezius, and pectoralis major during elbow extension-flexion. The voluntary extension-flexion angles of the elbow, the coactivation index of the biceps and triceps brachii muscles, synergy analysis, and the Action Research Arm Test (ARAT) scores were assessed before and after the HAL sessions; the FIM score was evaluated before and after the entire intervention. In Case 1, the voluntary extension angle tended to increase after the HAL sessions. In both cases, the ARAT scores improved after the sessions. The FIM scores improved after HAL intervention. The voluntary extension-flexion of the elbow using the HAL may be a feasible option for rehabilitation of CP patients.

We report a case in which elbow flexion exercises using the upper limb single-joint Hybrid Assistive Limb (upper limb HAL-SJ) were implemented in a patient 13 months postoperatively following elbow flexion reconstruction with intercostal nerve transfer after a traumatic brachial plexus injury. Treatment using the upper limb HAL-SJ was administered once a week for 10 sessions from 13 to 16 months after surgery. Exercises using the upper limb HAL-SJ supported elbow motion by detecting bioelectric signals through surface electrodes on the biceps and triceps brachii. No adverse events were observed during treatment with the upper limb HAL-SJ. Improvements in elbow flexion strength were observed during treatment. Treatment with the upper limb HAL-SJ can be performed safely and effectively following elbow flexion reconstruction by intercostal nerve transfer after a traumatic brachial plexus injury.

Background and Objectives: Dropped head syndrome (DHS) is characterized by apparent neck extensor muscle weakness and difficulty in extending the neck to raise the head against gravity. DHS affects forward vision and eating behavior, and hence impairs quality of life. However, standardized treatment of DHS has not yet been established. The purpose of this preliminary study is to seek for a possibility of effective non-surgical, conservative treatment for DHS, by applying a robotic treatment. Materials and Methods: A wearable exoskeleton type robot suit hybrid assistive limb (HAL) was applied to three patients with DHS. A course of HAL treatment included 10 sessions of gait training using HAL. One session lasted about an hour. Case 1 completed the course twice, the first time in two weeks (one session per day) and second time in 10 months (one session per month). Case 2 and Case 3 completed the course once in 10 weeks (one session per week) and in 6 months (one session per 2.5 weeks), respectively. Immediate and lasting effects of HAL on the reduction of cervical sagittal vertical alignment (SVA) during gait was evaluated using a motion capture system. Results: Case 1 showed improvement of cervical alignment during gait after the HAL courses of both different frequencies. Case 2 did not show improvement of cervical alignment during gait. Case 3 showed improvement of cervical kyphosis but not of cervical sagittal alignment during gait. Conclusions: The results of the preliminary study suggest that gait training using HAL may be an effective option of conservative treatment for a part of DHS patients. They also suggest that a lack of immediate effects on the cervical alignment and a lack of ability to perform compensatory trunk motion may indicate a non-responding patient. Generalization of the results requires further research with more cases.

This study aimed to evaluate the effectiveness and safety of using the upper limb single-joint Hybrid Assistive Limb (upper limb HAL-SJ) during elbow flexion training following elbow flexor reconstruction for brachial plexus injury (BPI). We present the cases of two patients in whom the upper limb HAL-SJ was implemented 5 and 7 months postoperatively following elbow flexor reconstruction for BPI. They underwent elbow flexor reconstruction with intercostal nerve crossing-to-musculocutaneous nerve (ICN-MCN crossing) after BPI. Postoperative training using the upper limb HAL-SJ was started from the Medical Research Council (MRC) grade 1 elbow flexion power to MRC grade 3 once every week or every 2 weeks. Both patients could implement elbow training using the upper limb HAL-SJ even in MRC grade 1 of their elbow flexion power. Training with the upper limb HAL-SJ was performed safely and effectively in two patients with elbow flexor reconstruction with ICN crossing after BPI.

The Ossification of the Posterior Longitudinal Ligament (OPLL) is an idiopathic degenerative spinal disease which may cause motor deficit. For patients presenting myelopathy or severe stenosis, surgical decompression is the treatment of choice; however, despite adequate decompression residual motor impairment is found in some cases. After surgery, there is no therapeutic approach available for this population. The Hybrid Assistive Limb® (HAL) robot suit is a unique powered exoskeleton designed to predict, support, and enhance the lower extremities performance of patients using their own bioelectric signals. This approach has been used for spinal cord injury and stroke patients where the walking performance improved. However, there is no available data about gait kinematics evaluation after HAL therapy. Here we analyze the effect of HAL therapy in OPLL patients in acute and chronic stages after decompression surgery. We found that HAL therapy improved the walking performance for both groups. Interestingly, kinematics evaluation by the analysis of the elevation angles of the thigh, shank, and foot by using a principal component analysis showed that planar covariation, plane orientation, and movement range evaluation improved for acute patients suggesting an improvement in gait coordination. Being the first study performing kinematics analysis after HAL therapy, our results suggest that HAL improved the gait coordination of acute patients by supporting the relearning process and therefore reshaping their gait pattern.

The modified Steindler procedure—a reconstructive surgery used to restore elbow flexion following upper brachial plexus injuries—involves shifting the origins of the muscle groups responsible for wrist flexion and forearm pronation originating from the medial epicondyle to the proximal direction to be used as flexors of the elbow. In the postoperative rehabilitation, we focused on strengthening not only the transferred muscle but also the wrist extensor muscles as antagonist muscles. After reconstruction surgery for elbow flexion via the modified Steindler procedure for traumatic brachial plexus injury, we performed long-term rehabilitation to strengthen the antagonist muscles. As a result, in two cases, excellent elbow flexion strength and gripping strength were achieved, confirming the importance of the antagonist muscles.

Purpose. We evaluated improvements in gait after using the Hybrid Assistive Limb (HAL®) exoskeleton robot in a patient with late-onset neurological deterioration of lower extremity function after undergoing thoracic spine surgery for a myelopathy due to ossification of the ligamentum flavum. Case Presentation. A 70-year-old man participated in ten 20 min sessions of HAL intervention, twice weekly for five weeks. The effects of each HAL session were evaluated based on changes in performance on the 10 m walk test (10 MWT), lower limb kinematics quantified from motion capture, and the activation ratio of the gastrocnemius, measured before and after the intervention. Muscle activity was recorded using surface electromyography and synchronized to measured kinematics. The HAL intervention improved gait speed and step length, with an increase in the hip flexion angle during the swing phase and a decrease in the activation ratio of the gastrocnemius. The modified Ashworth scale improved from 1+ to 1 and International Standards for Neurological and Functional Classification of Spinal Cord Injury motor scores from 34 to 49. Conclusion. Intervention using the HAL exoskeleton robot may be an effective method to improve functional ambulation in patients with chronic spinal disorders.

Patients with complete paraplegia after spinal cord injury (SCI) are unable to stand or walk on their own. Standing exercise decreases the risk of decubitus ulcers, osteoporosis, and joint deformities in patients with SCI. Conventional gait training for complete paraplegia requires excessive upper limb usage for weight bearing and is difficult in cases of complete quadriplegia. The purpose of this study was to describe voluntary ambulation triggered by upper limb activity using the Hybrid Assistive Limb® (HAL) in patients with complete quadri/paraplegia after chronic SCI. Four patients (3 men, 1 woman) were enrolled in this study. The mean patient age ± standard deviation was 37.2 ± 17.8 (range, 20–67) years. Clinical evaluation before intervention revealed the following findings: case 1, neurological level C6, American Spinal Cord Injury Association impairment scale (AIS) grade B; case 2, T6, AIS A; case 3, T10 AIS A; and case 4, T11, AIS A. The HAL intervention consisted of 10 sessions. Each HAL session lasted 60–90 min. The HAL electrodes for hip and knee flexion-extension were placed on the anterior and posterior sides of the upper limbs contralaterally corresponding to each of the lower limbs. Surface electromyography (EMG) was used to evaluate muscle activity of the tensor fascia lata and quadriceps femoris (Quad) in synchronization with a Vicon motion capture system. The modified Ashworth scale (mAs) score was also evaluated before and after each session. All participants completed all 10 sessions. Cases 1, 2, and 3 demonstrated significant decreases in mAs score after the sessions compared to pre-session measurements. In all cases, EMG before the intervention showed no apparent activation in either Quad. However, gait phase dependent activity of the lower limb muscles was seen during voluntarily triggered ambulation driven by upper limb muscle activities. In cases 3 and 4, active contraction in both Quads was observed after intervention. These findings suggest that upper-limb-triggered HAL ambulation is a safe and feasible option for rehabilitation in patients with complete quadri/paraplegia caused by chronic SCI.

Purposes: To evaluate the feasibility of using the single-joint Hybrid Assistive Limb ® robot (HAL) to assist with shoulder flexion-extension in healthy adults, and to assess the capacity of the HAL to analyze the bioelectrical signals of muscle activity for shoulder flexion-extension. Methods: This cross-sectional feasibility study included six healthy adult men with no impairment in shoulder motion. The single-joint HAL was fixed to a custom-designed platform and upper arm attachment, and aligned 3 cm below the acromion process. Vital signs, shoulder fatigue, and shoulder pain were evaluated before and after the shoulder elevation exercise performed with and without the HAL. Activity of selected muscles of the shoulder was recorded using a wireless superficial electromyography device. Shoulder movement was captured using a three-dimensional motion analysis system. Results: The HAL supported smooth flexion-extension of the arm at the shoulder joint, with no negative effects on vital signs, shoulder fatigue, and shoulder pain. The HAL decreased muscle activity levels, with a 55% decrease in trapezius muscle activity. The upward rotation angle of the scapula was significantly lower with the HAL at 120° of shoulder flexion. Conclusion: The single-joint HAL provided safe and effective assistance to scapular plane shoulder flexion-extension among healthy adults.

The knee range of motion is an important outcome of total knee arthroplasty (TKA). According to previous studies, the knee range of motion temporarily decreases for approximately 1 month after TKA due to postoperative pain and quadriceps dysfunction following surgical invasion into the knee extensor mechanism. We describe our experience with a knee-extension training program based on a single-joint hybrid assistive limb (HAL-SJ, Cyberdyne Inc., Tsukuba, Japan) during the acute recovery phase after TKA. HAL-SJ is a wearable robot suit that facilitates the voluntary control of knee joint motion. A 76-year-old man underwent HAL-SJ-based knee-extension training, which enabled him to perform knee function training during the acute phase after TKA without causing increased pain. Thus, he regained the ability to fully extend his knee postoperatively. HAL-SJ-based knee-extension training can be used as a novel post-TKA rehabilitation modality.

Shoulder elevation, defined here as arm raising, being essential for activities of daily living, dysfunctions represent a substantial burden in patients' lives. Owing to the complexity of the shoulder joint, the tightly coordinated muscular activity is a fundamental component, and neuromuscular impairments have devastating effects. A single-joint shoulder type version of the Hybrid Assistive Limb (HAL) allowing motion assistance based on the intention of the user via myoelectric activation has recently been developed, and its safety was demonstrated for shoulder rehabilitation. Yet, little is known about the physiological effects of the device. This study aims to monitor the changes in muscle activity and motion during shoulder HAL rehabilitation in several patients suffering from shoulder elevation dysfunction from cervical radicular origin. 8 patients (6 males, 2 females, mean age 62.4 &#177 9.3 years old) with weakness of the deltoid muscle resulting from a damage to the C5 nerve root underwent HAL-assisted rehabilitation. We combined surface electromyography and three-dimensional motion capture to record muscular activity and kinematics. All participants showed functional recovery, with improvements in their Manual Muscle Testing (MMT) scores and range of motion (ROM). During training, HAL decreased the activity of deltoid and trapezius, significantly more for the latter, as well as the coactivation of both muscles. We also report a reduction of the characteristic shrugging compensatory motion which is an obstacle to functional recovery. This reduction was notably demonstrated by a stronger reliance on the deltoid rather than the trapezius, indicating a muscle coordination tending toward a pattern similar to healthy individuals. Altogether, the results of the evaluation of motion and muscular changes hint toward a functional recovery in acute, and chronic shoulder impairments from cervical radicular origin following shoulder HAL rehabilitation training and provide information on the physiological effect of the device. [ABSTRACT FROM AUTHOR]