Robot-assisted therapy for upper limb paresis after stroke: Use of robotic algorithms in advanced practice.

BACKGROUND: Rehabilitation of stroke-related upper limb paresis is a major public health issue. OBJECTIVE: Robotic systems have been developed to facilitate neurorehabilitation by providing key elements required to stimulate brain plasticity and motor recovery, namely repetitive, intensive, adaptative training with feedback. Although the positive effect of robot-assisted therapy on motor impairments has been well demonstrated, the effect on functional capacity is less certain. METHOD: This narrative review outlines the principles of robot-assisted therapy for the rehabilitation of post-stroke upper limb paresis. RESULTS: A paradigm is proposed to promote not only recovery of impairment but also function. CONCLUSION: Further studies that would integrate some principles of the paradigm described in this paper are needed.

Relation between Cortical Activation and Effort during Robot-Mediated Walking in Healthy People: A Functional Near-Infrared Spectroscopy Neuroimaging Study (fNIRS).

Force and effort are important components of a motor task that can impact rehabilitation effectiveness. However, few studies have evaluated the impact of these factors on cortical activation during gait. The purpose of the study was to investigate the relation between cortical activation and effort required during exoskeleton-mediated gait at different levels of physical assistance in healthy individuals. Twenty-four healthy participants walked 10 m with an exoskeleton that provided four levels of assistance: 100%, 50%, 0%, and 25% resistance. Functional near-infrared spectroscopy (fNIRS) was used to measure cerebral flow dynamics with a 20-channel (plus two reference channels) device that covered most cortical motor regions bilaterally. We measured changes in oxyhemoglobin (HbO2) and deoxyhemoglobin (HbR). According to HbO2 levels, cortical activation only differed slightly between the assisted conditions and rest. In contrast, bilateral and widespread cortical activation occurred during the two unassisted conditions (somatosensory, somatosensory association, primary motor, premotor, and supplementary motor cortices). A similar pattern was seen for HbR levels, with a smaller number of significant channels than for HbO2. These results confirmed the hypothesis that there is a relation between cortical activation and level of effort during gait. This finding should help to optimize neurological rehabilitation strategies to drive neuroplasticity.

Impact of Dose of Combined Conventional and Robotic Therapy on Upper Limb Motor Impairments and Costs in Subacute Stroke Patients: A Retrospective Study.

INTRODUCTION: Robot-based training integrated into usual care might optimize therapy productivity and increase treatment dose. This retrospective study compared two doses of an upper limb rehabilitation program combining robot-assisted therapy and occupational therapy on motor recovery and costs after stroke. METHODS: Thirty-six subacute stroke patients [Fugl-Meyer Assessment (FMA) score 32 ± 12 points; mean ± SD] underwent a combined program of 29 ± 3 sessions of robot-assisted therapy and occupational therapy. Scheduled session time for the higher dose group (HG) was 90 min (two 45-min sessions; n = 14) and for the lower dose group (LG) was 60 min (two 30-min sessions; n = 22). Pre-/post-treatment change in FMA score (ΔFMA, %), actual active time (min), number of movements and number of movements per minute per robot-assisted therapy session were compared between groups. The costs of the combined programs were also analyzed. RESULTS: ΔFMA did not differ significantly between groups; the HG improved by 16 ± 13 % and the LG by 11 ± 8%. A between-group difference was found for actual active time (p = 1.06E-13) and number of movements (p = 4.42E-2) but not for number of movements per minute during robot-assisted therapy: the HG performed 1,023 ± 344 movements over 36 ± 3 min and the LG performed 796 ± 301 movements over 29 ± 1 min. Both groups performed 28 movements per minute. The combined program cost was €2017 and €1162 for HG and LG, respectively. CONCLUSIONS: Similar motor improvements were observed following two doses of movement-based training. The reduction in scheduled session time did not affect the intensity of the practice and met economic constraints.

Comparison of active-assisted and active-unassisted robot-mediated upper limb therapy in subacute stroke.

BACKGROUND: Upper-limb robot-mediated therapy is usually carried out in active-assisted mode because it enables performance of many movements. However, assistance may reduce the patient's own efforts which could limit motor recovery. OBJECTIVE: The aim of this study was to compare the effects of active-assisted and active-unassisted robotic interactions on motor recovery in subacute stroke patients with moderate hemiparesis. METHODS: Fourteen patients underwent a 6-week combined upper limb program of usual therapy and robotic therapy using either the active-unassisted (n = 8) or active-assisted (n = 6) modes. In the active-assisted group, assistance was only provided for the first 3 weeks (1st period) and was then switched off for the remaining 3 weeks (2nd period). The Fugl-Meyer Assessment (FMA) was carried out pre- and post-treatment. The mean number of movements performed and the mean working distance during the 1st and 2nd periods were compared between groups. RESULTS: FMA score improved post-treatment in both groups with no between-group differences: active-assisted group: +8±6 pts vs active-unassisted group: +10±6 pts (ns). Between the 1st and 2nd periods, there was a statistical trend towards an improvement in the number of movements performed (p = 0.06) in the active-unassisted group (526±253 to 783±434, p = 0.06) but not in the active-assisted group (882±211 to 880±297, ns). Another trend of improvement was found for the working distance in the active-unassisted group (8.7±4.5 to 9.9±4.7, p = 0.09) but not in the active-assisted group (14.0±0 to 13.5±1.1, ns). CONCLUSIONS: The superiority of the non-assistive over assistive robotic modes has not been demonstrated. However, the non-assistive mode did not appear to reduce motor recovery in this population, despite the performance of fewer movements on shorter working distance compared with the group who had assistance. It seems that the requirement of effort could be a determinant factor for recovery in neurorehabilitation however further well-design studies are needed to fully understand this phenomenon.

Robot-Assisted Therapy in Upper Extremity Hemiparesis: Overview of an Evidence-Based Approach.

Robot-mediated therapy is an innovative form of rehabilitation that enables highly repetitive, intensive, adaptive, and quantifiable physical training. It has been increasingly used to restore loss of motor function, mainly in stroke survivors suffering from an upper limb paresis. Multiple studies collated in a growing number of review articles showed the positive effects on motor impairment, less clearly on functional limitations. After describing the current status of robotic therapy after upper limb paresis due to stroke, this overview addresses basic principles related to robotic therapy applied to upper limb paresis. We demonstrate how this innovation is an evidence-based approach in that it meets both the improved clinical and more fundamental knowledge-base about regaining effective motor function after stroke and the need of more objective, flexible and controlled therapeutic paradigms.

Can robot-based measurements improve prediction of motor performance after robot-assisted upper-limb rehabilitation in patients with moderate-to-severe sub-acute stroke?

PURPOSE: Patients with moderate-to-severe stroke-related upper limb impairment can benefit from repetitive robot-assisted training. However, predicting motor performance in these patients from baseline measurements, including robot-based parameters would help clinicians to provide optimal treatments for each individual. METHODS: Forty-six patients with sub-acute stroke underwent a 16-session upper limb rehabilitation combining usual care and robotic therapy. Motor outcomes (Fugl-Meyer Assessment Upper Extremity (FMA) score) were retrospectively analysed and potential predictors of motor outcome (including baseline FMA scores, kinematics and number of repetitions performed in the first session etc.) were determined. RESULTS: The 16-sessions upper limb combined training program led to significantly improved clinical outcomes (gains of 13.8±11.2 for total FMA score and 7.3±6.7 for FMA Shoulder/Elbow score). For the prediction model, time since stroke poorly explained the FMA total score (R2 < 35%). The model however found that time since stroke and initial value of FMA Shoulder/Elbow score were predictors of the FMA Shoulder/Elbow score: (R2 = 59.6%). CONCLUSION: This study found that clinical prediction of motor outcomes after moderate-to-severe upper-limb paresis is limited. However, initial proximal motor impairment severity predicted proximal motor performance. The value of baselines kinematics and of the number of repeated movements at initiation in the prediction would need further studies.

Combining Upper Limb Robotic Rehabilitation with Other Therapeutic Approaches after Stroke: Current Status, Rationale, and Challenges.

A better understanding of the neural substrates that underlie motor recovery after stroke has led to the development of innovative rehabilitation strategies and tools that incorporate key elements of motor skill relearning, that is, intensive motor training involving goal-oriented repeated movements. Robotic devices for the upper limb are increasingly used in rehabilitation. Studies have demonstrated the effectiveness of these devices in reducing motor impairments, but less so for the improvement of upper limb function. Other studies have begun to investigate the benefits of combined approaches that target muscle function (functional electrical stimulation and botulinum toxin injections), modulate neural activity (noninvasive brain stimulation), and enhance motivation (virtual reality) in an attempt to potentialize the benefits of robot-mediated training. The aim of this paper is to overview the current status of such combined treatments and to analyze the rationale behind them.

Does assist-as-needed upper limb robotic therapy promote participation in repetitive activity-based motor training in sub-acute stroke patients with severe paresis?

BACKGROUND: Repetitive, active movement-based training promotes brain plasticity and motor recovery after stroke. Robotic therapy provides highly repetitive therapy that reduces motor impairment. However, the effect of assist-as-needed algorithms on patient participation and movement quality is not known. OBJECTIVE: To analyze patient participation and motor performance during highly repetitive assist-as-needed upper limb robotic therapy in a retrospective study. METHODS: Sixteen patients with sub-acute stroke carried out a 16-session upper limb robotic training program combined with usual care. The Fugl-Meyer Assessment (FMA) score was evaluated pre and post training. Robotic assistance parameters and Performance measures were compared within and across sessions. RESULTS: Robotic assistance did not change within-session and decreased between sessions during the training program. Motor performance did not decrease within-session and improved between sessions. Velocity-related assistance parameters improved more quickly than accuracy-related parameters. CONCLUSIONS: An assist-as-needed-based upper limb robotic training provided intense and repetitive rehabilitation and promoted patient participation and motor performance, facilitating motor recovery.

Kinematic measures for upper limb motor assessment during robot-mediated training in patients with severe sub-acute stroke.

PURPOSE: Kinematic assessments are increasingly used as motor outcome measures during upper limb robot-assisted training, in addition to clinical scales. However, their relevance has not been evaluated much. METHODS: Thirty-eight patients with severe sub-acute stroke (age 56 ± 17 [19-87] years; time since stroke, 55 ± 22 days) carried out 16 sessions (average 3/week, 35 ± 15 days) of upper limb robot-assisted training combined with standard therapy. Pre/post motor performance was evaluated using the Fugl-Meyer Assessment scale, Motor Status Scale (MSS) and kinematic measures. Motor outcomes were compared and relationships between clinical and kinematic outcomes were analyzed. RESULTS: All clinical and kinematic outcomes improved after training (p <  0.01). FM score increased from 17.7 ± 10.0 to 28.6 ± 15.4. All baseline kinematic measures were strongly correlated with clinical scores. Correlations between clinical and kinematic changes were moderate (r = -0.65 for change in FM Proximal score and change in accuracy measure). However, smoothness and accuracy indicators were shown to be responsive measures. CONCLUSION: This study demonstrated that baseline kinematic measures and their pre/post training changes were significantly correlated with clinical motor outcome measures. However, even if kinematic measures are valid for the evaluation of motor impairment we cannot propose to substitute common clinical measures of motor function which also evaluate functional abilities of the upper limb.

Use of a robotic device for the rehabilitation of severe upper limb paresis in subacute stroke: exploration of patient/robot interactions and the motor recovery process.

This pioneering observational study explored the interaction between subacute stroke inpatients and a rehabilitation robot during upper limb training. 25 stroke survivors (age 55 ± 17 years; time since stroke, 52 ± 21 days) with severe upper limb paresis carried out 16 sessions of robot-assisted shoulder/elbow training (InMotion 2.0, IMT, Inc., MA, USA) combined with standard therapy. The values of 3 patient/robot interaction parameters (a guidance parameter: Stiffness, a velocity-related parameter: Slottime, and Robotic Power) were compared between sessions 1 (S1), 4 (S4), 8 (S8), 12 (S12), and 16 (S16). Pre/post Fugl-Meyer Assessment (FMA) scores were compared in 18 patients. Correlations between interaction parameters and clinical and kinematic outcome measures were evaluated. Slottime decreased at S8 (P = 0.003), while Guidance decreased at S12 (P = 0.008). Robotic Power tended to decrease until S16. FMA scores improved from S1 to S16 (+49%, P = 0.002). Changes in FMA score were correlated with the Stiffness parameter (R = 0.4, P = 0.003). Slottime was correlated with movement velocity. This novel approach demonstrated that a robotic device is a useful and reliable tool for the quantification of interaction parameters. Moreover, changes in these parameters were correlated with clinical and kinematic changes. These results suggested that robot-based recordings can provide new insights into the motor recovery process.