Motor recovery patterns in arm muscles: coupled bilateral training and neuromuscular stimulation

Effects of wearable device training on upper limb motor function in patients with stroke: a systematic review and meta-analysis

OBJECTIVE

To evaluate the effect of wearable device training on improving upper limb motor function in patients who experienced strokes.

METHODS

The PubMed, Embase, Cochrane Library, Web of Science, MEDLINE, SCOPUS, China National Knowledge Infrastructure, WanFang, and VIP databases were searched for randomized controlled trials (RCTs) that assessed the effectiveness of wearable device training in improving upper limb motor function in patients with stroke. Two investigators independently screened studies by their titles and abstracts and cross-checked, downloaded, and evaluated the results. Disagreements were resolved by a third highly experienced researcher. Risk of bias was evaluated using the Cochrane risk-of-bias tool. This meta-analysis was registered in PROSPERO (registration No. CRD42023421633).

RESULTS

This study comprised 508 patients from 14 RCTs. The experimental group assessed various wearable devices, including 3D-printed dynamic orthoses, inertial measurement unit (IMU) sensors, electrical stimulation devices, and virtual reality (VR) devices for virtual interactive training. The control group received traditional rehabilitation therapies, including physical and conventional rehabilitation. The experimental group scored better on the Fugl-Meyer Assessment (FMA-UE) scale (standardized mean difference [SMD] 0.26, 95% confidence interval [CI] 0.07, 0.45) and Box and Block Test (BBT) (SMD 0.43, 95% CI 0.17, 0.69) versus controls. No significant intergroup differences were observed in the Action Research Arm Test (SMD 0.20, 95% CI -0.15, 0.55), motor activity log (mean difference [MD] 0.32, 95% CI -0.54, 0.33), and modified Ashworth scale (MD -0.08, 95% CI -0.81, 0.64). The probability rankings of wearable devices that improved FMA-UE scores in patients with stroke were: orthotic devices, with the highest probability ranking of 0.45, followed by sensor devices at 0.23, electrical stimulation devices at 0.21, and VR devices at 0.11.

CONCLUSIONS

Wearable device training was found to significantly improve upper limb motor function in patients with stroke, particularly for large-range movements. Improvements in FMA-UE and BBT scores reflected reduced impairment and enhanced manual dexterity, respectively. However, the training had no significant effect on hand movement frequency, fine motor skills, or spasticity. Among the different wearable devices tested, orthoses produced the most effective results.

Resistance band training with functional electrical stimulation improves force control capabilities in older adults: a preliminary study

Resistance band training (RBT) with functional electrical stimulation (FES) may be an effective exercise regimen for improving age-related motor impairments. This preliminary study investigated the potential effects of bimanual RBT with FES on upper limb motor functions in older adults. This study randomly assigned 22 elderly people to the bimanual RBT with FES (Bi-RBT+FES) group and the RBT without FES (Bi-RBT) group. All participants performed isometric hand-grip force control tasks in unimanual (dominant and non-dominant) and bimanual conditions before and after four weeks of exercise for each group. We quantified the mean force, force accuracy, force variability, and force regularity at two targeted force levels (i.e., 10 % and 40 % of maximum voluntary contraction; MVC) to estimate changes in force control capabilities. The results revealed that the Bi-RBT+FES group demonstrated a greater force accuracy in the dominant hand at 10 % of MVC after training. Non-dominant hands in the Bi-RBT+FES group increased force accuracy at 40 % of MVC and reduced force variability collapsed across two targeted force levels. Both groups showed a decrease in force regularity after training. These preliminary results indicate that Bi-RBT+FES may be a viable option to facilitate functional recovery of the upper limbs in older adults.

Encoder-Controlled Functional Electrical Stimulator for Bilateral Wrist Activities—Design and Evaluation

Upper limb impairment following stroke is often characterized by limited voluntary control in the affected arm. In addition, significant motor coordination problems occur on the unaffected arm due to avoidance of performing bilateral symmetrical activities. Rehabilitation strategies should, therefore, not only aim at improving voluntary control on the affected arm, but also contribute to synchronizing activity from both upper limbs. The encoder-controlled functional electrical stimulator, described in this paper, implements precise contralateral control of wrist flexion and extension with electrical stimulation. The stimulator is calibrated for each individual to obtain a table of stimulation parameters versus wrist angle. This table is used to set stimulation parameters dynamically, based on the difference in wrist angle between the set and stimulated side, which is continuously monitored. This allows the wrist on the stimulated side to follow flexion and extension patterns on the set side, thereby mirroring wrist movements of the normal side. This device also gives real-time graphical feedback on how the stimulated wrist is performing in comparison to the normal side. A study was performed on 25 normal volunteers to determine how closely wrist movements on the set side were being followed on the stimulated side. Graphical results show that there were minor differences, which were quantified by considering the peak angles of flexion and extension on the set and stimulated side for each participant. The mean difference in peak flexion and extension range of movement was 2.3 degrees and 1.9 degrees, respectively, with a mean time lag of 1 s between the set and the stimulated angle graphs.

Nonlinear functional muscle network based on information theory tracks sensorimotor integration post stroke

Sensory information is critical for motor coordination. However, understanding sensorimotor integration is complicated, especially in individuals with impairment due to injury to the central nervous system. This research presents a novel functional biomarker, based on a nonlinear network graph of muscle connectivity, called InfoMuNet, to quantify the role of sensory information on motor performance. Thirty-two individuals with post-stroke hemiparesis performed a grasp-and-lift task, while their muscle activity from 8 muscles in each arm was measured using surface electromyography. Subjects performed the task with their affected hand before and after sensory exposure to the task performed with the less-affected hand. For the first time, this work shows that InfoMuNet robustly quantifies changes in functional muscle connectivity in the affected hand after exposure to sensory information from the less-affected side. > 90% of the subjects conformed with the improvement resulting from this sensory exposure. InfoMuNet also shows high sensitivity to tactile, kinesthetic, and visual input alterations at the subject level, highlighting its potential use in precision rehabilitation interventions.

Paretic hand unimanual force control: Improved submaximal force production and regularity

The purpose was to investigate force control capabilities in paretic hands during unimanual movements after coupled bimanual movement training and neuromuscular stimulation on impaired muscles. Nineteen chronic stroke participants completed 90 min of rehabilitation per week for six consecutive weeks. Before and after training, volunteers performed unimanual submaximal force control tasks at 5% and 50% of maximum voluntary contraction with their paretic and non-paretic hands. Force control measures included submaximal force production, force variability, accuracy, and regularity. Two major findings on paretic hands after training revealed: (a) greater submaximal force production across force levels and (b) less regular force outputs. Paretic hand control improved after coupled bimanual movement training as evidenced by submaximal force production and force regularity.