Impaired Arm Research Articles

Myoelectric Computer Interface Training for Reducing Co-Activation and Enhancing Arm Movement in Chronic Stroke Survivors: A Randomized Trial

Background. Abnormal muscle co-activation contributes to impairment after stroke. We developed a myoelectric computer interface (MyoCI) training paradigm to reduce abnormal co-activation. MyoCI provides intuitive feedback about muscle activation patterns, enabling decoupling of these muscles. Objective. To investigate tolerability and effects of MyoCI training of 3 muscle pairs on arm motor recovery after stroke, including effects of training dose and isometric versus movement-based training. Methods. We randomized chronic stroke survivors with moderate-to-severe arm impairment to 3 groups. Two groups tested different doses of isometric MyoCI (60 vs 90 minutes), and one group tested MyoCI without arm restraint (90 minutes), over 6 weeks. Primary outcome was arm impairment (Fugl-Meyer Assessment). Secondary outcomes included function, spasticity, and elbow range-of-motion at weeks 6 and 10. Results. Over all 32 subjects, MyoCI training of 3 muscle pairs significantly reduced impairment (Fugl-Meyer Assessment) by 3.3 ± 0.6 and 3.1 ± 0.7 (P < 10−4) at weeks 6 and 10, respectively. Each group improved significantly from baseline; no significant differences were seen between groups. Participants’ lab-based and home-based function also improved at weeks 6 and 10 (P ≤ .01). Spasticity also decreased over all subjects, and elbow range-of-motion improved. Both moderately and severely impaired patients showed significant improvement. No participants had training-related adverse events. MyoCI reduced abnormal co-activation, which appeared to transfer to reaching in the movement group. Conclusions. MyoCI is a well-tolerated, novel rehabilitation tool that enables stroke survivors to reduce abnormal co-activation. It may reduce impairment and spasticity and improve arm function, even in severely impaired patients.

Participation, Fear of Falling, and Upper Limb Impairment are Associated with High Sitting Time in People with Stroke

The purpose of this cross-sectional, exploratory study was to explore associations between sitting time and (1) participation, (2) fear of falling, and (3) upper limb impairment after stroke. High sitting time was associated with less participation in meaningful activities involving standing or walking (ρ = −0.519, p = 0.023). A greater fear of falling (ρ = 0.579, p = 0.012) and having an impaired upper limb (mean difference 18.7%, 95% CI: 5.3–32.1, p = 0.012) were associated with greater sitting time. Providing support for stroke survivors to participate in meaningful activities while reducing sitting time is an important consideration when planning occupational therapy interventions, particularly for individuals with an arm impairment and/or those with a fear of falling.

Wristband Accelerometers to motiVate arm Exercises after Stroke (WAVES): a pilot randomized controlled trial

Objective: To evaluate the feasibility of a multicentre, observer-blind, pilot randomized controlled trial (RCT) of a wristband accelerometer with activity-dependent vibration alerts to prompt impaired arm use after stroke. Design: Parallel-group pilot RCT. Setting: Four English stroke services. Participants: Patients 0–3 months post stroke with a new arm deficit. Intervention: Participants were randomized to wear a prompting or ‘sham’ wristband during a four-week self-directed therapy programme with twice-weekly therapy review. Main outcomes: Recruitment, retention and adherence rates, safety and completion of assessments were reported. Arm recovery was measured by Action Research Arm Test (ARAT) and Motor Activity Log (MAL) without statistical comparison. Results: In total, 33 patients were recruited (0.6 per month/site; median time post stroke: 26 days (interquartile range (IQR):15.5–45)). Baseline, four-week and eight-week median (IQR) ARAT for the control group (n = 19) were 15 (2–35), 35 (15–26) and 31 (21–55) and those for the intervention group (n = 14) were 37 (16–45), 57 (29–57) and 57 (37–57), respectively; for MAL Amount of Use, the corresponding values in the control group were 0.2 (0.0–1.2), 1.1 (0.3–2.9) and 1.2 (0.7–2.9) and in the intervention group were 1.4 (0.5–2.6), 3.8 (1.9–4.5) and 3.7 (2.1–4.3). Four participants withdrew from the study. Wristbands were worn for 79% of the recommended time. The intervention and control group participants received a median of 6.0 (IQR: 4.3–8.0) and 7.5 (IQR: 6.8–8.0) therapy reviews. A median of 8 (IQR: 6–10) prompts were delivered per intervention participant/day. Research assessments were completed for 28/29 and 25/28 patients at four and eight weeks. Eight serious adverse events were reported, all unrelated to the intervention. Conclusion: A multicentre RCT of wristband accelerometers to prompt arm activity early after stroke is feasible. A total sample of 108 participants would be required.

Influence of target uncertainty on reaching movements while standing in stroke

Stroke individuals frequently have balance problems and impaired arm movements that affect their daily activities. We investigated the influence of target uncertainty and the side of the brain lesion on the performance of arm movements and postural adjustments during reaching in a standing position by stroke individuals. Participants stood on force plates and reached a target displayed on the center of a monitor screen under conditions differentiated by the prior knowledge of the target location at the beginning of the movement. Individuals who had a stroke in the right side of the brain performed the tasks with the ipsilesional, right upper limb while the individuals with a left stroke performed with the ipsilesional, left upper limb. Healthy individuals performed with right and left limbs, which data were later averaged for statistical analysis. Kinematic analysis of the arm and lower limb joints and displacements of the center of pressure of each lower limb were compared between target conditions and groups. Stroke individuals showed larger center of pressure displacements of the contralesional compared to the ipsilesional limb while these displacements were symmetrical between lower limbs for the healthy individuals, regardless of the target condition. The target uncertainty affected both the characteristics of the arm movements and postural adjustments before movement onset. Right stroke individuals used more ankle joint movements under the uncertain compared to the certain condition. The uncertainty in target location affects the arm reaching in upright standing, but the effects depend on the side of the brain lesion.

片側上肢切断・欠損パラリンピッククロスカントリースキー選手に対する姿勢・動作アセスメントに関する一考察

片側上肢切断・欠損パラリンピッククロスカントリースキー選手に対する姿勢・動作アセスメントに関する一考察

Outcome measures in post-stroke arm rehabilitation trials: do existing measures capture outcomes that are important to stroke survivors, carers, and clinicians?

Objective: We sought to (1) identify the outcome measures currently used across stroke arm rehabilitation randomized trials, (2) identify and compare outcomes important to stroke survivors, carers and clinicians and (3) describe where existing research outcome measures capture outcomes that matter the most to stroke survivors, carers and clinicians and where there may be discrepancies. Methods: First, we systematically identified and extracted data on outcome measures used in trials within a Cochrane overview of arm rehabilitation interventions. Second, we conducted 16 focus groups with stroke survivors, carers and clinicians using nominal group technique, supplemented with eight semi-structured interviews, to identify these stakeholders’ most important outcomes following post-stroke arm impairment. Finally, we described the constructs of each outcome measure and indicated where stakeholders’ important outcomes were captured by each measure. Results: We extracted 144 outcome measures from 243 post-stroke arm rehabilitation trials. The Fugl-Meyer Assessment Upper Extremity section (used in 79/243 trials; 33%), Action Research Arm Test (56/243; 23%), and modified Ashworth Scale (53/243; 22%) were most frequently used. Stroke survivors (n = 43), carers (n = 10) and clinicians (n = 58) identified 66 unique, important outcomes related to arm impairment following stroke. Between one and three outcomes considered important by the stakeholders were captured by the three most commonly used assessments in research. Conclusion: Post-stroke arm rehabilitation research would benefit from a reduction in the number of outcome measures currently used, and better alignment between what is measured and what is important to stroke survivors, carers and clinicians.

Loss of selective wrist muscle activation in post-stroke patients

Purpose: Loss of selective muscle activation after stroke contributes to impaired arm function, is difficult to quantify and is not systematically assessed yet. The aim of this study was to describe and validate a technique for quantification of selective muscle activation of wrist flexor and extensor muscles in a cohort of post-stroke patients. Patterns of selective muscle activation were compared to healthy volunteers and test-retest reliability was assessed.Materials and methods: Activation Ratios describe selective activation of a muscle during its expected optimal activation as agonist and antagonist. Activation Ratios were calculated from electromyography signals during an isometric maximal torque task in 31 post-stroke patients and 14 healthy volunteers. Participants with insufficient voluntary muscle activation (maximal electromyography signal <3SD higher than baseline) were excluded.Results: Activation Ratios at the wrist were reliably quantified (Intraclass correlation coefficients 0.77–0.78). Activation Ratios were significantly lower in post-stroke patients compared to healthy participants (p < 0.05).Conclusion: Activation Ratios allow for muscle-specific quantification of selective muscle activation at the wrist in post-stroke patients. Loss of selective muscle activation may be a relevant determinant in assigning and evaluating therapy to improve functional outcome.Implications for RehabilitationLoss of selective muscle activation after stroke contributes to impaired arm function, is difficult to quantify and is not systematically assessed yet.The ability for selective muscle activation is a relevant determinant in assigning and evaluating therapy to improve functional outcome, e.g., botulinum toxin.Activation Ratios allow for reliable and muscle-specific quantification of selective muscle activation in post-stroke patients.

Motion Tracking for Quantitative and Qualitative Assessment of Upper Limb Movements Following Acromioclavicular Joint Ligament Reconstruction: A Pilot Study

Background: Technological tools as robotic devices and wearable sensors can provide accurate and repeatable measurements of physical variables (e.g., position, velocities, forces) which can be used for quantitative and qualitative assessment of movement analysis and upper limb motor performance. Objective: The study aims to propose a quantitative and qualitative assessment of upper limb motor performance by means of seven kinematic parameters recorded by a passive mechatronic device in patients who underwent a surgical procedure for ligament reconstruction following acromioclavicular joint dislocation. Method: Five patients (mean age: 40 ± 12 years) with acromioclavicular joint dislocation were enrolled. A passive end-effector mechatronic device characterized by 7 degrees of freedom and designed for the assessment of upper limb motor performance - especially for measuring the hand position in three-dimensional space - was used. The Constant-Murley score and seven kinematic parameters were used as clinical outcome measure and quantitative and qualitative assessment, respectively. Results: The preliminary results of this study show no significant differences between the impaired arm and unimpaired arm: the end-effector passive mechatronic device used in this study is able to provide an overall assessment of the upper limb motor performance following shoulder impairment. Conclusion: The motion tracker can be easily used as effective tool for quantitative and qualitative assessment of upper limb motor performance, even several years after the surgical operation.

Managing the severely impaired arm after stroke: a mixed-methods study with qualitative emphasis

Purpose: There is a paucity of research into self-management strategies employed by stroke survivors outside of formal rehabilitation. This study aimed to explore stroke survivors’ experiences of, and strategies for self-managing their severely impaired upper limb.Materials and methods: English-speaking stroke survivors whose upper limb had been non-functional at 3 months post-stroke took part in interviews (n = 16), a focus group (n = 6) and a survey (n = 20). Quantitative data were analysed descriptively. Qualitative data were analysed through thematic framework analysis using NVivo© software.Results: Participants’ median (range) age group was 50–59 years (30–39, 70+). Median (range) time post-stroke was 39 months (4 months, 46 years). The overarching theme across the data was “choosing and expanding.” Participants enacted professionally driven management strategies for their affected arm, and then chose to continue with what worked for them. Strategies were expanded through self-discovery and interaction with peers. There were sadness and frustration at the loss of arm function, but also satisfaction and self-confidence when progress was being made. Participants described an attitude of not giving up and remaining hopeful.Conclusions: These findings extend our understanding about how individuals manage their severely impaired upper limb and can be used to inform a novel stroke self-management intervention.Implications for rehabilitationStroke survivors’ experiences of managing the severely affected upper limb may inform rehabilitation practice to foster self-management.Rehabilitation professionals may actively support stroke survivors in choosing from, and expanding on professionals’ advice and guidance.Maintaining a positive and hopeful outlook is important to many stroke survivors. Professionals should be mindful of the potential impact of their interactions and negative predictions.Stroke survivors’ experiences of managing the severely affected upper limb may inform the development of a novel tailored self-management intervention.

Effectiveness of Exercise Protocol on Upper Arm Dysfunction and Quality of Life among Women with Breast Cancer: Randomized Controlled Trial

Introduction: Upper arm dysfunction occurs after breast cancer surgery and include one or more of following arm impairments like decreased shoulder range of motion, strength, pain, numbness, swelling, weakness, and lymphedema. The objective of study was to assess the effectiveness of exercise protocol on upper arm dysfunction and quality of life (QOL) among women with breast cancer who have undergone mastectomy with axillary lymph node dissection. Methods: A randomized controlled trial (Time series design) included 44 women with breast cancer in All India Institute of Medical Sciences (AIIMS), New Delhi and who were scheduled for mastectomy with axillary lymph node dissection. Purposive sampling was done. Subjects were randomly allocated to experimental (n=22) and control group (n=22). However, 40 patients completed the study till 8 weeks. Subjects in experimental group received exercise protocol from post-surgery day 1 to 8 weeks while control group received standard routine care. Data regarding socio demographic and clinical characteristics were collected at baseline. Upper arm dysfunction and quality of life were assessed by structured questionnaires at baseline (post-surgery day 1) at 2 weeks and at 8 weeks. Results: The two groups were homogenous with regard to socio-demographic variables and clinical characteristics at baseline. The experimental group had significant reduction in upper arm dysfunction, seen by reduction in mean subjective symptom score (p<0.0001) and DASH scores (p<0.0001) as compared to control group. There was significant improvement in Quality of life scores in experimental group as compared to control group with p value <0.0001 indicating improvement in quality of life after 8 weeks of intervention. Conclusion: Exercise protocol administration from day 1 after surgery to 8 weeks was effective in reducing upper arm dysfunction and improving the quality of life among breast cancer patients who have undergone mastectomy with axillary lymph node dissection.

Dissociating motor learning from recovery in exoskeleton training post-stroke

BackgroundA large number of robotic or gravity-supporting devices have been developed for rehabilitation of upper extremity post-stroke. Because these devices continuously monitor performance data during training, they could potentially help to develop predictive models of the effects of motor training on recovery. However, during training with such devices, patients must become adept at using the new “tool” of the exoskeleton, including learning the new forces and visuomotor transformations associated with the device. We thus hypothesized that the changes in performance during extensive training with a passive, gravity-supporting, exoskeleton device (the Armeo Spring) will follow an initial fast phase, due to learning to use the device, and a slower phase that corresponds to reduction in overall arm impairment. Of interest was whether these fast and slow processes were related.MethodsTo test the two-process hypothesis, we used mixed-effect exponential models to identify putative fast and slow changes in smoothness of arm movements during 80 arm reaching tests performed during 20 days of exoskeleton training in 53 individuals with post-acute stroke.ResultsIn line with our hypothesis, we found that double exponential models better fit the changes in smoothness of arm movements than single exponential models. In contrast, single exponential models better fit the data for a group of young healthy control subjects. In addition, in the stroke group, we showed that smoothness correlated with a measure of impairment (the upper extremity Fugl Meyer score - UEFM) at the end, but not at the beginning, of training. Furthermore, the improvement in movement smoothness due to the slow component, but not to the fast component, strongly correlated with the improvement in the UEFM between the beginning and end of training. There was no correlation between the change of peaks due to the fast process and the changes due to the slow process. Finally, the improvement in smoothness due to the slow, but not the fast, component correlated with the number of days since stroke at the onset of training – i.e. participants who started exoskeleton training sooner after stroke improved their smoothness more.ConclusionsOur results therefore demonstrate that at least two processes are involved in in performance improvements measured during mechanized training post-stroke. The fast process is consistent with learning to use the exoskeleton, while the slow process independently reflects the reduction in upper extremity impairment.

Electrical Somatosensory Stimulation in Early Rehabilitation of Arm Paresis After Stroke: A Randomized Controlled Trial

Background. Arm paresis is present in 48% to 77% of acute stroke patients. Complete functional recovery is reported in only 12% to 34%. Although the arm recovery is most pronounced during the first 4 weeks poststroke, few studies examined the effect of upper extremity interventions during this period. Objective. To investigate the effect of electrical somatosensory stimulation (ESS) delivered during early stroke rehabilitation on the recovery of arm functioning. Methods. A total of 102 patients with arm paresis were randomized to a high-dose or a low-dose ESS group within 7 days poststroke according to our sample size estimation. The high-dose group received 1-hour ESS to the paretic arm daily during hospitalization immediately followed by minimum 15-minute task-oriented arm training that was considered a component of the usual rehabilitation. The low-dose group received a placebo ESS followed by identical training. Primary outcome—Box and Block Test (BBT); secondary outcomes—Fugl-Meyer Assessment (FMA), grip strength, pinch strength, perceptual threshold of touch, pain, and modified Rankin Scale (mRS); all recorded at baseline, postintervention and at 6 months poststroke. Results. There were no differences between the high-dose and the low-dose groups for any outcome measures at any time points. Improvements ⩾ minimal clinically important difference were observed for FMA, hand grip strength, and mRS in both groups. Conclusions. Providing the present ESS protocol prior to arm training was equally beneficial as arm training alone. These results are valid for patients with mild-to-moderate stroke and moderate arm impairments. We cannot exclude benefits in patients with other characteristics, in other time intervals poststroke or using a different ESS protocol. Trial Registration. ClinicalTrials.gov (NCT02250365).

A qualitative study exploring views and experiences of people with stroke undergoing transcranial direct current stimulation and upper limb robot therapy

Background: Neurorehabilitation technologies used mainly in research such as robot therapy (RT) and transcranial direct current stimulation (tDCS) can promote upper limb motor recovery after stroke. Understanding the feasibility and efficacy of stroke rehabilitation technologies for upper limb impairments is crucial for effective implementation in practice. Small studies have explored views of RT by people with stroke; however experiences of people receiving tDCS in combination with RT have never been explored.Objective: To explore views and experiences of people with sub-acute and chronic stroke that had previously taken part in a randomised controlled trial involving tDCS and RT for their impaired upper limb.Methods: An interview study includes open and closed questions. Face-to-face interviews were audio recorded. Open-ended question responses were transcribed and analyzed using thematic analysis; closed questions were analyzed using descriptive analysis.Results: Participants felt that RT was enjoyable (90%) and beneficial for their affected arm (100%). From the open question data, it was found that the intervention was effective for the impaired arm especially in the sub-acute stage. Main reported concerns were that tDCS caused painful, itching and burning sensations and RT was sometimes tiring and difficult. Participants recommended that future research should focus on designing a more comfortable method of tDCS and develop a robot that promotes hand movements.Conclusions: This study provides new knowledge about the benefits and barriers associated with these technologies which are crucial to the future effective implementation of these tools in practice.

Virtual Reality Computer Gaming with Dynamic Arm Support in Boys with Duchenne Muscular Dystrophy.

In boys with Duchenne muscular dystrophy (DMD), loss of upper limb function becomes more evident after the onset of wheelchair-dependency, because of the inability to lift the arms against gravity. With an increasing population of older wheelchair-dependent boys with DMD it is worthwhile to know whether training can delay the loss of upper limb functions. Dynamic arm supports may enable boys with impaired arm function to train their muscles without becoming exhausted by providing external mechanical compensation for muscle weakness. This study investigated the effect of gravity-compensated 3D-training for the arms on the functional abilities in boys with DMD. An explorative RCT was conducted among boys with DMD with impaired arm function (n = 16). Boys in the intervention group (n = 7) trained their arms by playing virtual reality games while using dynamic arm support during 20 weeks. The primary endpoint was the difference in change in Performance of the Upper Limb (PUL) score between the intervention and control group (n = 9) after 20 weeks. Secondary outcome measures were at the different ICF-CY levels. No significant group differences were found for the PUL. Elbow range of motion (p = 0.018) and extension strength (p = 0.038) improved in the intervention group and worsened in the control group. Although this study did not show a significant effect of training on the primary outcome measure, there are indications that training may decline the loss of range of motion and strength. This may prolong the functional abilities on long-term. Netherlands Trial Register 3857.

Recovery in the Severely Impaired Arm Post-Stroke After Mirror Therapy: A Randomized Controlled Study.

This study aimed to examine the effectiveness of mirror therapy on recovery in the severely impaired arm after stroke. Using single-blind randomized controlled design, patients with severely impaired arm within 1-month post-stroke were assigned to receive mirror therapy (n = 20) or control therapy (n = 21), 30 mins twice daily for 4 wks in addition to conventional rehabilitation. During mirror therapy and control therapy, subjects practiced similar structured exercises in both arms, except that mirror reflection of the unaffected arm was the visual feedback for mirror therapy, but mirror was absent for control therapy so that subjects could watch both arms in exercise. Fugl-Meyer Assessment and Wolf Motor Function Test were the outcome measurements. After the intervention, both mirror therapy and control therapy groups had significant arm recovery similarly in Fugl-Meyer Assessment (P = 0.867), Wolf Motor Function Test-Time (P = 0.947) and Wolf Motor Function Test-Functional Ability Scale (P = 0.676). Mirror therapy or control therapy, which involved exercises concurrently for the paretic and unaffected arms during subacute stroke, promoted similar motor recovery in the severely impaired arm.

A pilot study into reaching performance after severe to moderate stroke using upper arm support.

Stroke effects millions of people each year and can have a significant impact on the ability to use the impaired arm and hand. One of the results of stroke is the development of an abnormal shoulder-elbow flexion synergy, where lifting the arm can cause the elbow, wrist, and finger flexors to involuntarily contract, reducing the ability to reach with the arm and hand opening. This study explored the effect of using support at the upper arm to improve hand and arm reaching performance. Nine participants were studied while performing a virtual reaching task under three conditions: while the weight of their impaired arm was supported by a robot arm, while unsupported, and while using their non-impaired arm. Most subjects exhibited faster and more accurate reaching while supported compared to unsupported. For the subjects who could voluntarily open their hand, most were able to more swiftly open their hand when using upper arm support. In many cases, performance with support was not statistically different than the unaffected arm and hand. Muscle activity of the impaired limb with upper arm support showed decreased effort to lift the arm and reduced biceps activity in most subjects, pointing to a reduction in the abnormal flexion synergy while using upper arm support. While arm support can help to reduce the activation of abnormal synergies, weakness resulting from hemiparesis remains an issue impacting performance. Future systems will need to address both of these causes of disability to more fully restore function after stroke.

Wristband accelerometers to motivate arm exercise after stroke (WAVES): Activity data from a pilot randomised controlled trial

Encouraging impaired limb use during routine and rehabilitation activities after stroke is challenging. We evaluated changes in stroke arm activity related to vibration prompts delivered by a wrist-worn accelerometer (“CueS wristband”). A pilot randomised controlled trial was conducted with adults < 3 months after stroke causing any arm impairment. All received instruction for a self-directed four-week programme encouraging bimanual tasks, and wore a wristband on the impaired side 8am–8pm. Intervention wristbands were programmed to deliver vibration prompts if hourly activity targets were unmet. To allow for incremental recovery, patient preference and diurnal variability, the target was selected as 5%, 10% or 20% above median levels recorded hourly over the previous 3 days. Data were downloaded at twice weekly reviews. Activity counts per minute (CPM) were calculated from CueS mean signal vector magnitude (1 s epoch) at the first (baseline) and the last (endpoint) review. Standard accelerometers recorded natural arm activity over 72 h starting at 4 and 8 weeks post-baseline. Mann Whitney U test compared CPM between groups, and for 1 hour before/after prompts amongst intervention participants. Thirty-three participants (14 intervention; 19 control) enrolled over 16 months: mean age 71 years (SD11); 13 male; mean days post-stroke 30 (SD19); median baseline Action Research Arm Test 20/57 [IQR 3.5,41]. Median number of prompts delivered were 7 per participant/day [IQR: 6,8]. Median CPM during 1 hour before/after prompts was 651 versus 759 (+16.6%; P = 0.002). CPM increased immediately after prompting, suggesting a direct behavioural impact. Compared to control, the intervention group continued to increase CPM beyond wristband removal. Whilst these results are encouraging, this was a small study and data may not reflect only arm activity. Personalised prompts delivered by a wrist-worn accelerometer may enhance self-directed arm activity after stroke.

The effect of myoelectric computer interface training on arm kinematics and function after stroke.

Abnormal co-activation patterns of arm muscles is a substantial cause of impaired arm function after stroke. We designed a myoelectric computer interface (MCI) training paradigm to help stroke survivors reduce this abnormal coactivation. Here, we evaluated the effects of MCI training on function and arm kinematics in 32 chronic stroke survivors. We compared the effects of training duration and isometric vs. movement-based training conditions in 3 different groups. All groups reduced abnormal co-activation in targeted muscles, and showed reduced arm impairment after 6 weeks of training. They also showed improvements in arm kinematics as well as functional scores. Moreover, the gains persisted, though most were reduced, at one month after training stopped. These results suggest that MCI training holds promise to improve arm function after stroke.

Evolution of Neuroprosthetic Approaches to Restoration of Upper Extremity Function in Spinal Cord Injury.

Background: Spinal cord injury (SCI) occurring at the cervical levels can result in significantly impaired arm and hand function. People with cervical-level SCI desire improved use of their arms and hands, anticipating that regained function will result in improved independence and ultimately improved quality of life. Neuroprostheses provide the most promising method for significant gain in hand and arm function for persons with cervical-level SCI. Neuroprostheses utilize small electrical currents to activate peripheral motor nerves, resulting in controlled contraction of paralyzed muscles. Methods: A myoelectrically-controlled neuroprosthesis was evaluated in 15 arms in 13 individuals with cervical-level SCI. All individuals had motor level C5 or C6 tetraplegia. Results: This study demonstrates that an implanted neuroprosthesis utilizing myoelectric signal (MES)-controlled stimulation allows considerable flexibility in the control algorithms that can be utilized for a variety of arm and hand functions. Improved active range of motion, grip strength, and the ability to pick up and release objects were improved in all arms tested. Adverse events were few and were consistent with the experience with similar active implantable devices. Conclusion: For individuals with cervical SCI who are highly motivated, implanted neuroprostheses provide the opportunity to gain arm and hand function that cannot be gained through the use of orthotics or surgical intervention alone. Upper extremity neuroprostheses have been shown to provide increased function and independence for persons with cervical-level SCI.

Upper Limb Kinematics in Stroke and Healthy Controls Using Target-to-Target Task in Virtual Reality.

Kinematic analysis using virtual reality (VR) environment provides quantitative assessment of upper limb movements. This technique has rarely been used in evaluating motor function in stroke despite its availability in stroke rehabilitation. To determine the discriminative validity of VR-based kinematics during target-to-target pointing task in individuals with mild or moderate arm impairment following stroke and in healthy controls. Sixty-seven participants with moderate (32-57 points) or mild (58-65 points) stroke impairment as assessed with Fugl-Meyer Assessment for Upper Extremity were included from the Stroke Arm Longitudinal study at the University of Gothenburg-SALGOT cohort of non-selected individuals within the first year of stroke. The stroke groups and 43 healthy controls performed the target-to-target pointing task, where 32 circular targets appear one after the other and disappear when pointed at by the haptic handheld stylus in a three-dimensional VR environment. The kinematic parameters captured by the stylus included movement time, velocities, and smoothness of movement. The movement time, mean velocity, and peak velocity were discriminative between groups with moderate and mild stroke impairment and healthy controls. The movement time was longer and mean and peak velocity were lower for individuals with stroke. The number of velocity peaks, representing smoothness, was also discriminative and significantly higher in both stroke groups (mild, moderate) compared to controls. Movement trajectories in stroke more frequently showed clustering (spider's web) close to the target indicating deficits in movement precision. The target-to-target pointing task can provide valuable and specific information about sensorimotor impairment of the upper limb following stroke that might not be captured using traditional clinical scale. The trial was registered with register number NCT01115348 at clinicaltrials.gov, on May 4, 2010. URL: https://clinicaltrials.gov/ct2/show/NCT01115348.