Robot-assisted support combined with electrical stimulation for the lower extremity in stroke patients: a systematic review.

Objective. The incidence of stroke rising, leading to an increased demand for rehabilitation services. Literature has consistently shown that early and intensive rehabilitation is beneficial for stroke patients. Robot-assisted devices have been extensively studied in this context, as they have the potential to increase the frequency of therapy sessions and thereby the intensity. Robot-assisted systems can be combined with electrical stimulation (ES) to further enhance muscle activation and patient compliance. The objective of this study was to review the effectiveness of ES combined with all types of robot-assisted technology for lower extremity rehabilitation in stroke patients.Approach. A thorough search of peer-reviewed articles was conducted. The quality of the included studies was assessed using a modified version of the Downs and Black checklist. Relevant information regarding the interventions, devices, study populations, and more was extracted from the selected articles.Main results. A total of 26 articles were included in the review, with 23 of them scoring at least fair on the methodological quality. The analyzed devices could be categorized into two main groups: cycling combined with ES and robots combined with ES. Overall, all the studies demonstrated improvements in body function and structure, as well as activity level, as per the International Classification of Functioning, Disability, and Health model. Half of the studies in this review showed superiority of training with the combination of robot and ES over robot training alone or over conventional treatment.Significance. The combination of robot-assisted technology with ES is gaining increasing interest in stroke rehabilitation. However, the studies identified in this review present challenges in terms of comparability due to variations in outcome measures and intervention protocols. Future research should focus on actively involving and engaging patients in executing movements and strive for standardization in outcome values and intervention protocols.

Effect of assist-as-needed robotic gait training on the gait pattern post stroke: a randomized controlled trial.

BACKGROUND: Regaining gait capacity is an important rehabilitation goal post stroke. Compared to clinically available robotic gait trainers, robots with an assist-as-needed approach and multiple degrees of freedom (AANmDOF) are expected to support motor learning, and might improve the post-stroke gait pattern. However, their benefits compared to conventional gait training have not yet been shown in a randomized controlled trial (RCT). The aim of this two-center, assessor-blinded, RCT was to compare the effect of AANmDOF robotic to conventional training on the gait pattern and functional gait tasks during post-stroke inpatient rehabilitation. METHODS: Thirty-four participants with unilateral, supratentorial stroke were enrolled (< 10 weeks post onset, Functional Ambulation Categories 3-5) and randomly assigned to six weeks of AANmDOF robotic (combination of training in LOPES-II and conventional gait training) or conventional gait training (30 min, 3-5 times a week), focused on pre-defined training goals. Randomization and allocation to training group were carried out by an independent researcher. External mechanical work (WEXT), spatiotemporal gait parameters, gait kinematics related to pre-defined training goals, and functional gait tasks were assessed before training (T0), after training (T1), and at 4-months follow-up (T2). RESULTS: Two participants, one in each group, were excluded from analysis because of discontinued participation after T0, leaving 32 participants (AANmDOF robotic n = 17; conventional n = 15) for intention-to-treat analysis. In both groups, WEXT had decreased at T1 and had become similar to baseline at T2, while gait speed had increased at both assessments. In both groups, most spatiotemporal gait parameters and functional gait tasks had improved at T1 and T2. Except for step width (T0-T1) and paretic step length (T0-T2), there were no significant group differences at T1 or T2 compared to T0. In participants with a pre-defined goal aimed at foot clearance, paretic knee flexion improved more in the AANmDOF robotic group compared to the conventional group (T0-T2). CONCLUSIONS: Generally, AANmDOF robotic training was not superior to conventional training for improving gait pattern in subacute stroke survivors. Both groups improved their mechanical gait efficiency. Yet, AANmDOF robotic training might be more effective to improve specific post-stroke gait abnormalities such as reduced knee flexion during swing. Trial registration Registry number Netherlands Trial Register ( www.trialregister.nl ): NTR5060. Registered 13 February 2015.

Detection of the Intention to Grasp During Reaching in Stroke Using Inertial Sensing.

To support stroke survivors in activities of daily living, wearable soft-robotic gloves are being developed. An essential feature for use in daily life is detection of movement intent to trigger actuation without substantial delays. To increase efficacy, the intention to grasp should be detected as soon as possible, while other movements are not detected instead. Therefore, the possibilities to classify reach and grasp movements of stroke survivors, and to detect the intention of grasp movements, were investigated using inertial sensing. Hand and wrist movements of 10 stroke survivors were analyzed during reach and grasp movements using inertial sensing and a Support Vector Machine classifier. The highest mean accuracies of 96.8% and 83.3% were achieved for single- and multi-user classification respectively. Accuracies up to 90% were achieved when using 80% of the movement length, or even only 50% of the movement length after choosing the optimal kernel per person. This would allow for an earlier detection of 300-750ms, but at the expense of accuracy. In conclusion, inertial sensing combined with the Support Vector Machine classifier is a promising method for actuation of grasp-supporting devices to aid stroke survivors in activities of daily living. Online implementation should be investigated in future research.

Detection of the intention to grasp during reach movements.

INTRODUCTION: Soft-robotic gloves have been developed to enhance grip to support stroke patients during daily life tasks. Studies showed that users perform tasks faster without the glove as compared to with the glove. It was investigated whether it is possible to detect grasp intention earlier than using force sensors to enhance the performance of the glove. METHODS: This was studied by distinguishing reach-to-grasp movements from reach movements without the intention to grasp, using minimal inertial sensing and machine learning. Both single-user and multi-user support vector machine classifiers were investigated. Data were gathered during an experiment with healthy subjects, in which they were asked to perform grasp and reach movements. RESULTS: Experimental results show a mean accuracy of 98.2% for single-user and of 91.4% for multi-user classification, both using only two sensors: one on the hand and one on the middle finger. Furthermore, it was found that using only 40% of the trial length, an accuracy of 85.3% was achieved, which would allow for an earlier prediction of grasp during the reach movement by 1200 ms. CONCLUSIONS: Based on these promising results, further research will be done to investigate the possibility to use classification of the movements in stroke patients.

The influence of a user-adaptive prosthetic knee across varying walking speeds: A randomized cross-over trial.

Previously conducted trials comparing the gait pattern of individuals with a transfemoral amputation using a user-adaptive and a non-microprocessor-controlled prosthetic knee (NMPK) found mixed and conflicting results. Few trials, however, have compared user-adaptive to non-adaptive prosthetic knees across different walking speeds. Because of the ability of variable damping, the effect of user-adaptive knees might be more pronounced at lower or higher walking speeds. Our aim was to compare the Rheo Knee II (a microprocessor-controlled prosthetic knee) with NMPKs across varying walking speeds. In addition, we studied compensatory mechanisms associated with non-optimal prosthetic knee kinematics, such as intact ankle vaulting and vertical acceleration of the pelvis. Nine persons with a transfemoral amputation or knee disarticulation were included and measured with their own NMPK and with the Rheo Knee II. Measurements were performed at three walking speeds: preferred walking speed, 70% preferred walking speed and 115% preferred walking speed. No differences on peak prosthetic knee flexion during swing were found between prosthetic knee conditions. In addition, prosthetic knee flexion increased significantly with walking speed for both prosthetic knee conditions. At 70% preferred walking speed we found that vaulting of the intact ankle was significantly decreased while walking with the Rheo Knee II compared to the NMPK condition (P=0.028). We did not find differences in peak vertical acceleration of the pelvis during initial and mid-swing of the prosthetic leg. In conclusion, comparison of walking with the Rheo Knee II to walking with a NMPK across different walking speeds showed limited differences in gait parameters.

SOFIE, a bicycle that supports older cyclists?

Older cyclists remain at high risk of sustaining an injury after a fall with their bicycle. A growing awareness for the need and possibilities to support safety of older cyclists has been leading to bicycle design ideas. However, the effectiveness and acceptance of such designs has not been studied yet. This study aims to analyse the effect of 3 support systems: an automatic adjustable saddle height, optimised frame and wheel geometry and drive-off assistance. The support systems are integrated on the SOFIE bicycle, a prototype bicycle designed to support older cyclists during (dis-)mounting and at lower cycling speeds. Nine older cyclists (65-80 years) were asked to cycle on a 'normal' and on the 'SOFIE' bicycle. They cycled on a parking lot to avoid interaction with traffic. The following tasks were analysed: cycling at comfortable and low speed avoiding an obstacle and (dis-)mounting the bicycle. Bicycle and cyclist motions were recorded with 10 Inertial Measurement Units and by 2 video cameras. FUSION software (LABVIEW) was used to assess kinematic parameters. First, a subjective analysis of the different cycling tasks was made, supported by video analysis. Second, differences in cyclist and bicycle kinematic parameters between the normal and SOFIE bicycle were studied for the various cycling tasks. The SOFIE bicycle was experienced as a 'supportive' and comfortable bicycle and objectively performed 'safer' on various cycling tasks. For example: The optimised frame geometry with low step-in enabled a faster (dis-)mounting time and less sternum roll angle and angular acceleration. The adjustable saddle height enabled the participants to keep both feet on the ground till they started cycling with the 'drive-off' support. The latter reduces steering activity: maximum steer angle and angular acceleration. During sudden obstacle avoidance, less upper body and thigh accelerations are recorded. In conclusion, the SOFIE bicycle was able to support older cyclists during various cycling tasks and may reduce fall risk.

Detection of the onset of gait initiation using kinematic sensors and EMG in transfemoral amputees.

In this study we determined if detection of the onset of gait initiation in transfemoral amputees can be useful for voluntary control of upper leg prostheses. From six transfemoral amputees inertial sensor data and EMG were measured at the prosthetic leg during gait initiation. First, initial movement was detected from the inertial sensor data. Subsequently it was determined whether EMG could predict initial movement before detection based on the inertial sensors with comparable consistency as the inertial sensors. From the inertial sensors the initial movement can be determined. If the prosthetic leg leads, the upper leg accelerometer data was able to detect initial movement best. If the intact leg leads the upper leg gyroscope data performed best. Inertial sensors at the upper leg in general showed detections at the same time or earlier than those at the lower leg. EMG can predict initial movement up to a 138 ms in advance, when the prosthetic leg leads. One subject showed consistent EMG onset up to 248 ms before initial movement in the intact leg leading condition. A new method to detect initial movement from inertial sensors was presented and can be useful for additional prosthetic control. EMG measured at the prosthetic leg can be used for prediction of gait initiation when the prosthetic leg is leading, but for the intact leg leading condition this will not be of additional value.

A feasibility study of the effect of multichannel electrical stimulation and gravity compensation on hand function in stroke patients: a pilot study.

Many stroke patients have to cope with impaired arm and hand function. As a feasibility study, gravity compensation (GC) and multichannel electrical stimulation (ES) were applied to the forearm of eight stroke patients to study potential effects on dexterity. ES was triggered by positional data of the subject's hand relative to the objects that had to be grasped. Dexterity was evaluated by means of the Box and Blocks Test (BBT). The BBT was performed with four combinations of support; with and without GC and with and without ES. In all patients, it was possible to induce sufficient hand opening for grasping a block of the BBT by means of ES. There was no significant increase in dexterity as measured with the BBT. GC and/or ES did not improve instantaneous dexterity in a small sample of stroke patients although sufficient hand opening was reached in all patients. More research in a larger sample of stroke patients with more specific and more sophisticated control algorithms is needed to explore beneficial effects of GC and ES on hand function in post stroke rehabilitation.

Application of arm support training in sub-acute stroke rehabilitation: first results on effectiveness and user experiences.

A multi-center randomized clinical trial was performed in 7 Dutch rehabilitation centers, in the context of an implementation project (ROBAR), to compare the effect of an arm support (AS) training device to equally intensive conventional reach training (CON) on recovery of arm-hand function in sub-acute stroke. The Fugl-Meyer assessment (FM) and user experiences of therapists and patients were examined in both groups. An improvement of 10 and 8 points on the FM was found for respectively the CON and AS group. Both therapists and patients reported positive experiences on several aspects of user acceptance. These findings indicate that a low-tech system for arm support results in similar gains in arm function as conventional reach training in equal intensity, and is suitable for application in clinical practice.

Intention detection of gait initiation using EMG and kinematic data.

Gait initiation in transfemoral amputees (TFA) is different from non-amputees. This is mainly caused by the lack of stability and push-off from the prosthetic leg. Adding control and artificial push-off to the prosthesis may therefore be beneficial to TFA. In this study the feasibility of real-time intention detection of gait initiation was determined by mimicking the TFA situation in non-amputees. EMG and inertial sensor data was measured in 10 non-amputees. Only data available in TFA was used to determine if gait initiation can be predicted in time to control a transfemoral prosthesis to generate push-off and stability. Toe-off and heel-strike of the leading limb are important parameters to be detected, to control a prosthesis and to time push-off. The results show that toe-off and heel-strike of the leading limb can be detected using EMG and kinematic data in non-amputees 130-260 ms in advance. This leaves enough time to control a prosthesis. Based on these results we hypothesize that similar results can be found in TFA, allowing for adequate control of a prosthesis during gait initiation.

Variable stiffness actuated prosthetic knee to restore knee buckling during stance: a modeling study.

Most modern intelligent knee prosthesis use dampers to modulate dynamic behavior and prevent excessive knee flexion, but they dissipate energy and do not assist in knee extension. Energy efficient variable stiffness control (VSA) can reduce the energy consumption yet effectively modulate the dynamic behavior and use stored energy during flexion to assist in subsequent extension. A principle design of energy efficient VSA in a prosthetic knee is proposed and analyzed for the specific case of rejection of a disturbed stance phase. The concept is based on the principle that the output stiffness of a spring can be changed without changing the energy stored in the elastic elements of the spring. The usability of this concept to control a prosthetic knee is evaluated using a model. Part of the stance phase of the human leg was modeled by a double pendulum. Specifically the rejection of a common disturbance of transfemoral prosthetic gait, an unlocked knee at heel strike, was evaluated. The ranges of spring stiffnesses were determined such that the angular characteristics of a normal stance phase were preserved, but disturbances could also be rejected. The simulations predicted that energy efficient VSA can be useful for the control of prosthetic knees.

Simulated bone remodeling around two types of osseointegrated implants for direct fixation of upper-leg prostheses.

Direct attachment of an upper leg prosthesis to the skeletal system by a percutaneous implant is an alternative solution to the traditional socket fixation. In this study, we investigated long-term periprosthetic bone changes around two types of fixation implants using two different initial conditions, namely immediate post-amputation implantation and the conventional implantation after considerable time of socket prosthesis use. We questioned the difference in bone modeling response the implants provoked and if it could lead to premature bone fracture. Generic CT-based finite element models of an intact femoral bone and amputated bone implanted with models of two existing direct-fixation implants, the OPRA system (Integrum AB) and the ISP Endo/Exo prosthesis (ESKA Implants AG) were created for this study. Adaptive bone-remodeling simulations used the heel-strike and toe-off loads from a normal walking cycle. The bone loss caused by prolonged use of socket prosthesis had more severe effects on the ultimate bone quality than adaptation induced by the direct-fixation implants. Both implants showed considerable bone remodeling; the titanium screw implant (OPRA system) provoked more bone loss than the porous coated CoCrMo stem (ISP implant). The chance of the peri-prosthetic bone fracture remained higher for the post-socket case as compared to the direct amputation cases. In conclusion, both direct-fixation implants lead to considerable bone loss and bone loss is more severe after a prolonged period of post-socket use. Hence, from a biomechanical perspective it is better to limit the post-socket time and to re-design direct fixation devices to reduce bone loss and the probability of peri-prosthetic bone fractures.

Vibro- and electrotactile user feedback on hand opening for myoelectric forearm prostheses.

Many of the currently available myoelectric forearm prostheses stay unused because of the lack of sensory feedback. Vibrotactile and electrotactile stimulation have high potential to provide this feedback. In this study, performance of a grasping task is investigated for different hand opening feedback conditions on 15 healthy subjects and validated on three patients. The opening of a virtual hand was controlled by a scroll wheel. Feedback about hand opening was given via an array of eight vibrotactile or electrotactile stimulators placed on the forearm, relating to eight hand opening positions. A longitudinal and transversal orientation of the array and four feedback conditions were investigated: no feedback, visual feedback, feedback through vibrotactile or electrotactile stimulation, and addition of an extra stimulator for touch feedback. No influence of array orientation was shown for all outcome parameters (duration of the task, the percentage of correct hand openings, the mean position error, and the percentage deviations up to one position). Vibrotactile stimulation enhances the performance compared to the nonfeedback conditions. The addition of touch feedback further increases the performance, but at the cost of an increased duration. The same effects were found for the patient group, but the task duration was around 25% larger.

An explorative study into changes in circle drawing after gravity compensation training in chronic stroke patients.

A way to reduce the influence of abnormal synergies on range of motion after stroke directly is to support the arm by a robotic gravity compensation device. However, it is not known whether a period of training with arm support improves independent, unsupported circle drawing, and what the role of abnormal synergies is. Seven chronic stroke patients received three 30 minute robotic gravity compensation training sessions per week for a period of six weeks. During baseline and evaluation measurements, Fugl-Meyer (FM) scores and circle drawing performance (area and roundness) were determined. After training, FM had improved in some subjects. Circle area increased significantly across subjects, whereas roundness did not. This indicates an improved unsupported active range of motion, but the influence of (reduced) abnormal synergies on this change remains unclear. Despite the small number of subjects, the present explorative study suggests that robotic gravity compensation training has the potential to increase the work area of the affected arm of chronic stroke patients. Further research into the impact of robotic gravity compensation training is warranted, to enhance insight into underlying mechanisms and optimal applications in clinical practice.

Objective measurement of synergistic movement patterns of the upper extremity following stroke: an explorative study.

The majority of stroke survivors have to cope with deficits in arm function, which is often monitored with subjective clinical scales during stroke rehabilitation. The aim of this study is to examine whether robotic outcome measures obtained during circle drawing are suitable to objectively measure upper extremity function of stroke survivors, especially regarding synergistic movement patterns. Stroke survivors (n = 16) and healthy subjects (n = 20) drew circles, as big and as round as possible, above a table top. Joint angles and positions of the shoulder and elbow were measured. Synergistic movement patterns were identified based on simultaneous changes of the shoulder elevation angle and elbow angle. Stroke survivors moved significantly more within synergistic movement patterns, compared to healthy subjects. Strong correlations between the proximal upper extremity part of the Fugl-Meyer (FM) scale and the use of synergistic movement patterns were found. The proposed outcome measures seem to be suitable measures to objectively quantify the occurrence of synergistic movement patterns of the upper extremity following stroke.

Vibrotactile stimulation of the upper leg: effects of location, stimulation method and habituation.

In this study vibrotactile stimulation of the upper leg and its usability for feedback was tested. Three experiments were performed on ten healthy subjects using pager motors. The first experiment was to test the perception of the vibration at different frequencies and at different locations of the upper leg. The second experiment tested the ability of subjects to estimate location and number of stimuli in an array. In addition it was evaluated whether simultaneous or sequential stimulation is better interpretable. Thirdly the habituation of the vibration was determined. The experiments showed that vibrotactile stimulation is well perceived and can be useful in providing feedback on the upper leg. Further experiments are needed to determine the effectiveness of vibrotactile stimulation for feedback in trans-femoral prostheses.

Stop using the Ashworth Scale for the assessment of spasticity.

AIM: Many studies have been performed on the methodological qualities of the (modified) Ashworth Scale but overall these studies seem inconclusive. The aim of this study was to investigate the construct validity and inter-rater reliability of the Ashworth Scale (AS) for the assessment of spasticity in the upper and lower extremities. METHOD: A cross-sectional study on spasticity in the elbow flexors (part 1) and knee extensors (part 2) was carried out. In both parts AS was assessed while muscle activity and resistance were recorded simultaneously in patients with upper motor neuron syndrome. Each patient was measured by three raters. RESULTS: 30 patients participated, 19 in each part of the study. For elbow flexor muscles, AS was not significantly associated with electromyographic parameters, except for rater 2 (rho = 0.66, p<0.01). A significant moderate association was found with resistance (0.54< or = rho < or =0.61, p<0.05). For knee extensors, AS scores were moderately associated with muscle activity (0.56< or = rho < or =0.66, p<0.05) and also with resistance (0.55< or = rho < or =0.87, p<0.05). The intraclass correlation coefficient for absolute agreement was 0.58 for elbow flexors and 0.63 for knee extensors. In linear mixed model analysis, the factor rater appeared to be highly associated with AS. CONCLUSION: The validity and reliability of the AS is insufficient to be used as a measure of spasticity.

Perception of lower limb spasticity in patients with spinal cord injury.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: To study the manifestation of spasticity in daily life of the patients with spinal cord injury, their perception of spasticity and spasticity-related discomfort. SETTING: Rehabilitation center in the Netherlands. METHODS: Twenty-six patients with motor complete spinal cord injury (SCI) and spasticity in the lower limbs completed a questionnaire. The following outcome measures were used: manifestation of spasticity, activities during which spasticity occurs, perceived degree of spasticity and resulting discomfort, measured with visual analog scale (VAS) and Borg scale, respectively. RESULTS: In general, spasticity manifested as extensor spasms (84.6%), flexor spasms and/or clonus (both 69.2%), and less often as continuous tension (57.7%). The registered activities were categorized into five main groups: 'changing position' was the largest group (22.0%) with a median VAS of 6.8 (range: 2.5-9.5) and median Borg scale of 3.0 (range: 1.0-7.0). Other groups of activities were 'making a transfer' (20.7%), 'activities of daily living' (17.1%), 'being active' (17.1%) and 'stable body position' (12.2%). The overall correlation between VAS and Borg was moderate (Spearman's rho=0.53, P=0.005). CONCLUSIONS: Patients with complete SCI experienced several manifestations of spasticity, extensor spasms being the most common. Many daily life activities elicited different manifestations of spasticity. The experienced discomfort was only moderately related to the perceived degree of spasticity during an activity. Possibly, the discomfort is influenced by other factors than the perceived spasticity alone.

Patient ratings of spasticity during daily activities are only marginally associated with long-term surface electromyography.

AIM: To investigate the association between subjective spasticity ratings and objective spasticity measurement using a new tool for spasticity assessment, that is long-term surface electromyography (sEMG) recordings during daily activities. For monitoring, processing and analysis of this long-term sEMG data, a muscle activity detection algorithm was developed. METHOD: sEMG of the rectus femoris, vastus lateralis, adductor group and semitendinosus of 14 complete spinal-cord-injured patients, in whom voluntary muscle contraction was absent, was recorded continuously during daily activities. Synchronously, subjects stored their activities in a diary and scored their experienced level of spasticity on the Visual Analogue Scale (VAS) for that particular activity. sEMG data were analysed using a high-quality burst-detection algorithm that was developed and validated within this study. Derived sEMG parameters were clustered using principal-component analysis (PCA) and used in a linear mixed model analysis to study their association with VAS. RESULTS: VAS scores appeared significantly associated with the PCA components representing the number and the duration of bursts, but not burst amplitude. Furthermore, VAS scores were associated with the activity performed. The percentage explained variance was, however, low, that is 27-35%. CONCLUSIONS: Patient ratings of the level of spasticity appear poorly associated with spasticity in terms of involuntary muscle activity assessed with long-term sEMG recordings. It is likely that other factors such as pain and cognitions are also incorporated in these patient ratings. Clinicians are therefore strongly advised to perform complementary objective assessments using long-term sEMG recordings.

Efficacy of intrathecal baclofen delivery in the management of severe spasticity in upper motor neuron syndrome.

In the treatment of patients with severe spasticity, intrathecal administration of baclofen (ITB) was introduced in order to exert its effect directly at the receptor sites in the spinal cord, and have better therapeutic efficacy with smaller drug doses compared to oral antispasmodic medications. Apart from our own research in Groningen, a review is performed to present and discuss the efficacy of ITB in patients with spasticity and hypertonia as symptoms of the upper motor neuron syndromes. The majority of the ITB studies describe proven efficacy in the reduction of spasticity and spasms in short-term and long-term follow-up. Functional improvements in daily care, hygiene, pain, etc are described but not often with reliable and validated instruments. A few studies reported significant improvement in walking performance in ambulant patients. The studies that have been done on the efficacy of ITB in relation to quality of life (QOL) showed some evidence of improvement. Future research is needed on fine tuning in the ITB therapy using functional assessment instruments.