Effectiveness of motor imagery or mental practice in functional recovery after stroke: a systematic review

Effects of motor imagery training on gait performance in individuals after stroke: a systematic review and meta-analysis

PURPOSE

This review systematically explores and summarise the effects of motor imagery training (MIT) compared to conventional therapy on gait performance in individuals after stroke.

MATERIALS AND METHODS

Randomised controlled trials (RCTs) were systematically searched in five electronic databases (PubMed, EMBASE, PsycINFO, OVID Nursing and CINAHL) from inception to 30 December 2022. Studies investigating MITs, targeted at individuals after stroke were eligible. Data were extracted related to study and intervention characteristics.

RESULTS

Sixteen studies were included. Compared with 'routine methods of treatment or training', the meta-analyses showed that MIT was more effective in improving cadence immediately post intervention (SMD: 1.22, 95% CI: 0.59, 1.85, p = 0.0001, I2 = 25%) and at 1- or 2-months post intervention (SMD: 0.78, 95% CI: 0.35, 1.20, p = 0.0004, I2 = 46%). The results also showed that MIT improves the step length of the affected side and the unaffected side at 1- or 2-months post intervention. Separate meta-analyses were also conducted on different tests of walking endurance (assessed by the 6-Minute Walk Test) and functional mobility (assessed by the Timed-Up-and-Go test).

CONCLUSIONS

MIT effectively improved gait performance. The findings in individuals after stroke remain inconclusive due to significant heterogeneity in included studies.

Event-Related EEG Desynchronization Reveals Enhanced Motor Imagery From the Third Person Perspective by Manipulating Sense of Body Ownership With Virtual Reality for Stroke Patients

Virtual reality (VR)-based rehabilitation training holds great potential for post-stroke motor recovery. Existing VR-based motor imagery (MI) paradigms mostly focus on the first-person perspective, and the benefit of the third-person perspective (3PP) remains to be further exploited. The 3PP is advantageous for movements involving the back or those with a large range because of its field coverage. Some movements are easier to imagine from the 3PP. However, the 3PP training efficiency may be unsatisfactory, which may be attributed to the difficulty encountered when generating a strong sense of ownership (SOO). In this work, we attempt to enhance a visual-guided 3PP MI in stroke patients by eliciting the SOO over a virtual avatar with VR. We propose to achieve this by inducing the so-called out-of-body experience (OBE), which is a full-body illusion (FBI) that people misperceive a 3PP virtual body as his/her own (i.e., generating the SOO to the virtual body). Electroencephalography signals of 13 stroke patients are recorded while MI of the affected upper limb is being performed. The proposed paradigm is evaluated by comparing event-related desynchronization (ERD) with a control paradigm without FBI induction. The results show that the proposed paradigm leads to a significantly larger ERD during MI, indicating a bilateral activation pattern consistent with that in previous studies. In conclusion, 3PP MI can be enhanced in stroke patients by eliciting the SOO through induction of the "OBE" FBI. This study offers more possibilities for virtual rehabilitation in stroke patients and can further facilitate VR application in rehabilitation.

Prefrontal cortex activity of active motion, cyclic electrical muscle stimulation, assisted motion, and imagery of wrist extension in stroke using fNIRS

OBJECTIVES

This study aimed to determine whether the prefrontal cortex (PFC) was activated during four training approaches for wrist extension in patients with stroke, including active motion, cyclic electrical muscle stimulation (EMS), assisted motion, and motor imagery (MI).

MATERIALS AND METHODS

We conducted a cross-sectional study involving 16 patients with stroke, and adopted functional near-infrared spectroscopy (fNIRS) to observe PFC activity during four treatment paradigms. The beta value of 53 channels in fNIRS under each paradigm, compared to the baseline, was evaluated using single sample t-test. The one-way analysis of variance with post hoc analysis was employed to compare the difference of significantly activated channels among four treatment paradigms.

RESULTS

This study revealed that the active motion (t values ranging from 2.399 to 4.368, p values <0.05), as well as MI of wrist extension (t values ranging from 2.161 to 4.378, p values <0.05), significantly increased HBO concentration across the entire PFC. The cyclic EMS enhanced the activation of Broca's area and frontal pole (FP) (t values ranging from -2.540 to 2.303, p values <0.05). The assisted motion induced significant activation in Broca's area, dorsolateral prefrontal cortex, and FP (t values ranging from -2.226 to 3.056, p values <0.05). The difference in ΔHBO among the four tasks was seen in Broca's area, FP, and frontal eye field.

CONCLUSIONS

Active wrist extension and MI activate most PFC areas, whereas assisted motion and single-use of cyclic EMS have limited effectiveness for PFC activation in stroke patients.

Evaluation of residual cognition in patients with disorders of consciousness based on functional near-infrared spectroscopy

SIGNIFICANCE

Accurate evaluation of consciousness in patients with prolonged disorders of consciousness (DOC) is critical for designing therapeutic plans, determining rehabilitative services, and predicting prognosis. Effective ways for detecting consciousness in patients with DOC are still needed.

AIM

Evaluation of the residual awareness in patients with DOC and investigation of the spatiotemporal differences in the hemodynamic responses between the minimally conscious state (MCS) and the unresponsive wakefulness syndrome (UWS) groups using active command-driven motor imagery (MI) tasks.

APPROACH

In this study, functional near-infrared spectroscopy (fNIRS) was used to measure the changes of hemodynamic responses in 19 patients with DOC (9 MCS and 10 UWS) using active command-driven MI tasks. The characteristics of the hemodynamic responses were extracted to compare the differences between the MCS and UWS groups. Moreover, the correlations between the hemodynamic responses and the clinical behavioral evaluations were also studied.

RESULTS

The results showed significant differences in the spatiotemporal distribution of the hemodynamic responses between the MCS and UWS groups. For the patients with MCS, significant increases in task-evoked hemodynamic responses occurred during the "YES" questions of the command-driven MI tasks. Importantly, these changes were significantly correlated with their coma-recovery scale-revised (CRS-R) scores. However, for the patients with UWS, no significant changes of the hemodynamic responses were found. Additionally, the results did not show any statistical correlation between the hemodynamic responses and their CRS-R scores.

CONCLUSIONS

The fNIRS-based command-driven MI tasks can be used as a promising tool for detecting residual awareness in patients with DOC. We hope that the findings and the active paradigm used in this study will provide useful insights into the diagnosis, therapy, and prognosis of this challenging patient population.

Effects of the Practice of Movement Representation Techniques in People Undergoing Knee and Hip Arthroplasty: A Systematic Review

OBJECTIVE

To analyze the effects of movement representation techniques (MRT) combined with conventional physical therapy (CFT) in people undergoing knee and hip arthroplasty compared to conventional physical therapy alone in terms of results in physical and functionality variables, cognitive function, and quality of life.

METHODOLOGY

the review was carried out according to the criteria of the PRISMA statement, considering studies in the electronic databases PubMed/Medline, Pubmed Central/Medline, Web of Science, EBSCO, and ScienceDirect.

RESULTS

MRT plus CFT generated therapeutic effects in some aspects of the physical variables: 100% pain (7 of 7 studies); 100% strength (5 out of 5 studies); range of motion 87.5% (7 out of 8 studies); 100% speed (1 of 1 study), functional variables: 100% gait (7 of 7 studies); functional capacity 87.5% (7 out of 8 studies); cognitive variables: 100% motor visualization ability (2 out of 2 studies); cognitive performance 100% (2 of 2 studies); and quality of life 66.6% (2 of 3 studies). When comparing its effects with conventional physical therapy, the variables that reported the greatest statistically significant changes were motor visualization ability, speed, pain, strength and gait. The most used MRT was motor imagery (MI), and the average time extension of therapies was 3.5 weeks.

CONCLUSIONS

movement representation techniques combined with conventional physical therapy are an innocuous and low-cost therapeutic intervention with therapeutic effects in patients with knee arthroplasty (KA) and hip arthroplasty (HA), and this combination generates greater therapeutic effects in physical, functional, and cognitive variables than conventional physical therapy alone.

Mental Practice and Manipulative Skills Training Among People With Multiple Sclerosis: A Pilot Study

IMPORTANCE

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system that produces both motor and cognitive dysfunctions. Impairments in limb function as a result of MS cause a decline in the performance of activities of daily living (ADLs).

OBJECTIVE

To determine whether the use of mental practice (MP) or MP combined with training in motor manipulation skills (skills training) would improve gross and fine motor skills and treatment satisfaction among people with MS.

DESIGN

Pilot study with a duration of 3 mo plus 3-mo follow-up.

SETTING

Two MS associations.

PARTICIPANTS

Thirty-five patients diagnosed with MS of the relapsing-remitting and progressive secondary subtypes, ages 25 to 60 yr.

INTERVENTION

The participants were allocated to one of three groups according to their order of inclusion in the study: (1) MP, (2) MP + skills training, or (3) control group. The treatment protocol had a 6-wk duration and a total of 12 sessions. Outcomes and Measures: Blinded evaluators performed three assessments for each patient (pretreatment, posttreatment, and 3-mo follow-up) using the Nine-Hole Peg Test, Box and Block Test, ABILHAND, and Canadian Occupational Performance Measure (COPM).

RESULTS

We found no evidence of benefits in self-perceived performance of ADLs with respect to gross and fine motor skills; however, there was an improvement in perceived satisfaction and in the performance of activities, independent of the treatment received.

CONCLUSIONS AND RELEVANCE

Perceived ADL performance and satisfaction with performance increases among people with MS when they receive MP, MP + skills training, and conventional rehabilitation treatment. What This Article Adds: Mental practice combined with conventional treatment could contribute to patients perceiving improved performance of ADLs. Self-reported outcome measures, such as the COPM, could provide highly valuable information about occupation performance that may not match the objective evidence.

Clinical Effectiveness and Cost-effectiveness of Videoconference-Based Integrated Cognitive Behavioral Therapy for Chronic Pain: Randomized Controlled Trial

BACKGROUND

Cognitive behavioral therapy is known to improve the management of chronic pain. However, the components of this therapy are still being investigated and debated.

OBJECTIVE

This study aimed to examine the effectiveness of an integrated cognitive behavioral therapy program with new components (attention-shift, memory work, video feedback, and image training) delivered via videoconferencing.

METHODS

This study was unblinded and participants were recruited and assessed face-to-face in the outpatient department. We conducted a randomized controlled trial for chronic pain to compare 16 weekly videoconference-based cognitive behavioral therapy (vCBT) sessions provided by a therapist with treatment as usual (TAU). Thirty patients (age range, 22-75 years) with chronic pain were randomly assigned to either vCBT (n=15) or TAU (n=15). Patients were evaluated at week 1 (baseline), week 8 (midintervention), and week 16 (postintervention). The primary outcome was the change in pain intensity, which was recorded using the numerical rating scale at 16 weeks from the baseline. Secondary outcomes were pain severity and pain interference, which were assessed using the Brief Pain Inventory. Additionally, we evaluated disability, pain catastrophizing cognition, depression, anxiety, quality of life, and cost utility.

RESULTS

In the eligibility assessment, 30 patients were eventually randomized and enrolled; finally, 15 patients in the vCBT and 14 patients in the TAU group were analyzed. Although no significant difference was found between the 2 groups in terms of changes in pain intensity by the numerical rating scale scores at week 16 from baseline (P=.36), there was a significant improvement in the comprehensive evaluation of pain by total score of Brief Pain Inventory (-1.43, 95% CI -2.49 to -0.37, df=24; P=.01). Further, significant improvement was seen in pain interference by using the Brief Pain Inventory (-9.42, 95% CI -14.47 to -4.36, df=25; P=.001) and in disability by using the Pain Disability Assessment Scale (-1.95, 95% CI -3.33 to -0.56, df=24; P=.008) compared with TAU. As for the Medical Economic Evaluation, the incremental cost-effectiveness ratio for 1 year was estimated at 2.9 million yen (about US $25,000) per quality-adjusted life year gained.

CONCLUSIONS

The findings of our study suggest that integrated cognitive behavioral therapy delivered by videoconferencing in regular medical care may reduce pain interference but not pain intensity. Further, this treatment method may be cost-effective, although this needs to be further verified using a larger sample size.

TRIAL REGISTRATION

University Hospital Medical Information Network UMIN000031124; https://tinyurl.com/2pr3xszb.

The effects of physical training versus combined action observation and motor imagery in conjunction with physical training on upper-extremity performance

INTRODUCTION

Combined action observation and motor imagery training (AO+MI training), which involves motor imagery during action observation and physical training, has been attracting attention as an effective strategy for learning motor skills. However, little has been reported on the effects of AO+MI training. In the present study, we compared the effects of AO+MI training to the effects of physical training on upper-extremity performance.

MATERIALS AND METHODS

Ninety-six healthy participants were randomly assigned to either the control group or the experimental group. Sport stacking, which is often used to evaluate upper-extremity performance, was adopted for the task. The experiment was scheduled for three days. The training was 20 min per day. The control group performed only physical training, while the experimental group performed four 5-min AO+MI training sessions. Time taken to complete a sport stacking try (task completion time) was defined as the index of speed of upper-extremity performance and number of fallen cups as the index of its accuracy. The outcomes within each group and between the two groups were compared.

RESULTS

Both AO+MI training and physical training showed reduced task completion time and increased number of fallen cups. There were no significant differences in the degree of changes between the groups.

CONCLUSION

Results from the present study showed that AO+MI training and physical training had almost the same influence on upper-extremity performance in the early stages of learning sport stacking. This result suggests that AO+MI training may be an effective and low-burden training method for participants.

Does Real-Time Feedback Affect Sensorimotor EEG Patterns in Routine Motor Imagery Practice?

Background. Motor imagery engages much of the same neural circuits as an overt movement. Therefore, the mental rehearsal of movements is often used to supplement physical training and might aid motor neurorehabilitation after stroke. One attempt to capture the brain’s involvement in imagery involves the use, as a marker, of the depression or event-related desynchronization (ERD) of thalamocortical sensorimotor rhythms found in a human electroencephalogram (EEG). Using fast real-time processing, it is possible to make the subject aware of their own brain reactions or—even better—to turn them into actions through a technology called the brain–computer interface (BCI). However, it remains unclear whether BCI-enabled imagery facilitates a stronger or qualitatively different brain response compared to the open-loop training. Methods. Seven healthy volunteers who were experienced in both closed and open-loop motor imagery took part in six experimental sessions over a period of 4.5 months, in which they performed kinesthetic imagery of a previously known set of finger and arm movements with simultaneous 30-channel EEG acquisition. The first and the last session mostly consisted of feedback trials in which the subjects were presented with the classification results of the EEG patterns in real time; during the other sessions, no feedback was provided. Spatiotemporal and amplitude features of the ERD patterns concomitant with imagery were compared across experimental days and between feedback conditions using linear mixed-effects modeling. Results. The main spatial sources of ERD appeared to be highly stable across the six experimental days, remaining nearly identical in five of seven subjects (Pearson’s ρ > 0.94). Only in one subject did the spatial pattern of activation statistically significantly differ (p = 0.009) between the feedback and no-feedback conditions. Real-time visual feedback delivered through the BCI did not significantly increase the ERD strength. Conclusion. The results imply that the potential benefits of MI could be yielded by well-habituated subjects with a simplified open-loop setup, e.g., through at-home self-practice.

Is motor imagery effective for gait rehabilitation after stroke? A cochrane review summary with commentary

BACKGROUND

Motor imagery (MI) is a promising therapeutic technique for stroke rehabilitation.

OBJECTIVE

To assess the effects of MI on gait rehabilitation after stroke.

METHODS

To summarize the "Cochrane Review" by Silva et al.RESULTS:Twenty-one studies with 762 participants were included in the Cochrane review. Very low level of certainty evidence pointed to some beneficial effects of MI alone or combined with action observation or physical practice on walking speed compared to other therapies. There is uncertainty about the effect of MI compared to other therapies in terms of motor function or functional mobility.

CONCLUSIONS

High-quality adequately powered studies investigating the effects of MI in individuals with stroke should be encouraged.

An evolutionary approach to hypnotizability

We propose here an evolutionary interpretation of the presence of highly hypnotizable persons (highs) among the general population. Current experimental evidence suggests the presence of stronger functional equivalence between imagery and perception, non-opioid cognitive control of pain, favorable cardiovascular asset, and greater interoceptive sensitivity in highs. We hypothesize that these characteristics were greatly relevant to our ancestors' survival, and that they may have facilitated the natural selection of individuals who are now named "highs" due to one of their side effects - the proneness to accept suggestions - as part of the reported physiological features. Unfortunately, our theoretical hypothesis cannot be currently experimentally proven. We believe, however, that looking at hypnotizability in a naturalistic, evolutionary perspective may emphasize the importance of its physiological correlates in daily life and in the prediction of the outcome of medical treatments.

Decoding of Ankle Joint Movements in Stroke Patients Using Surface Electromyography

Stroke is a cerebrovascular disease (CVD), which results in hemiplegia, paralysis, or death. Conventionally, a stroke patient requires prolonged sessions with physical therapists for the recovery of motor function. Various home-based rehabilitative devices are also available for upper limbs and require minimal or no assistance from a physiotherapist. However, there is no clinically proven device available for functional recovery of a lower limb. In this study, we explored the potential use of surface electromyography (sEMG) as a controlling mechanism for the development of a home-based lower limb rehabilitative device for stroke patients. In this experiment, three channels of sEMG were used to record data from 11 stroke patients while performing ankle joint movements. The movements were then decoded from the sEMG data and their correlation with the level of motor impairment was investigated. The impairment level was quantified using the Fugl-Meyer Assessment (FMA) scale. During the analysis, Hudgins time-domain features were extracted and classified using linear discriminant analysis (LDA) and artificial neural network (ANN). On average, 63.86% ± 4.3% and 67.1% ± 7.9% of the movements were accurately classified in an offline analysis by LDA and ANN, respectively. We found that in both classifiers, some motions outperformed others (p < 0.001 for LDA and p = 0.014 for ANN). The Spearman correlation (ρ) was calculated between the FMA scores and classification accuracies. The results indicate that there is a moderately positive correlation (ρ = 0.75 for LDA and ρ = 0.55 for ANN) between the two of them. The findings of this study suggest that a home-based EMG system can be developed to provide customized therapy for the improvement of functional lower limb motion in stroke patients.

Promising Effect of Visually-Assisted Motor Imagery Against Arthrogenic Muscle Inhibition - A Human Experimental Pain Study

Purpose

Clinically, arthrogenic muscle inhibition (AMI) has a negative impact on functional recovery in musculoskeletal disorders. One possible technique to relieve AMI is motor imagery, which is widely used in neurological rehabilitation to enhance motor neuron excitability. The purpose of this study was to verify the efficacy of visually-assisted motor imagery against AMI using a human experimental pain model.

Methods

Ten healthy volunteers were included. Experimental ankle pain was induced by hypertonic saline infusion into unilateral Kager’s fat pad. Isotonic saline was used as control. Subjects were instructed to imagine while watching a movie in which repetitive motion of their own ankle or fingers was shown. H-reflex normalized by the motor response (H/M ratio) on soleus muscle, maximal voluntary contraction (MVC) force of ankle flexion, and contractile activities of the calf muscles during MVC were recorded at baseline, pre-intervention, post-intervention, and 10 minutes after the pain had subsided.

Results

Hypertonic saline produced continuous and constant peri-ankle pain (VAS peak [median]= 6.7 [2.1–8.4] cm) compared to isotonic saline (0 [0–0.8] cm). In response to pain, there were significant decreases in the H/M ratio, MVC and contractile activities (P<0.01), all of which were successfully reversed after the ankle motion imagery. In contrast, no significant changes were observed with the finger motion imagery.

Conclusion

Visually-assisted motor imagery improved the pain-induced AMI. Motor imagery of the painful joint itself would efficiently work for relieving AMI. This investigation possibly shows the potential of a novel and versatile approach against AMI for patients with musculoskeletal pain.

The changes in spinal reciprocal inhibition during motor imagery in lower extremity

Motor imagery (MI) is known to improve motor function through enhancement of motor cortex activity. Spinal reciprocal inhibition (RI) is modulated by motor cortex activity, and, therefore, MI may change RI. The aim of this study was to examine the changes in RI during MI involving the lower extremity. Spinal RI was measured from the tibialis anterior (TA) to the soleus (SOL). Eleven healthy adults participated in experiment 1. All participants performed the following three conditions, and RI was assessed during each condition: (1) resting condition; (2) MI of ankle dorsiflexion condition (MI-DF); and (3) MI of ankle plantarflexion condition (MI-PF). Twelve healthy adults participated in experiment 2. All participants performed the following two conditions, and RI was assessed before and after MI practice for 10 min: (1) resting condition and (2) MI-DF. The interval between the conditioning and test stimulus (inter-stimulus interval; ISI) was set at 0, 1, 2, or 3 ms and 20 ms. In experiment 1, RI during MI-PF was significantly decreased compared with that during resting with both stimulus intervals. RI during MI-DF showed no significant change compared with that during resting with both ISIs. In experiment 2, the difference between the rest condition and the MI-DF condition after the MI task with ISI of 20 ms was significantly higher than before the MI task. Our findings suggest that real-time changes in RI during MI involving the lower extremity may vary depending on the direction of motion and MI practice.

Effects of Motor Imagery Training on Balance and Gait in Older Adults: A Randomized Controlled Pilot Study

The aim of this study was to demonstrate the effects of motor imagery training on balance and gait abilities in older adults and to investigate the possible application of the training as an effective intervention against fall prevention. Subjects (n = 34) aged 65 years and over who had experienced falls were randomly allocated to three groups: (1) motor imagery training group (MITG, n = 11), (2) task-oriented training group (TOTG, n = 11), and (3) control group (CG, n = 12). Each group performed an exercise three times a week for 6 weeks. The dependent variables included Path Length of center of pressure (COP)-based static balance, Berg Balance Scale (BBS) score, Timed Up and Go Test (TUG) score, which assesses a person's mobility based on changes in both static and dynamic balance, Falls Efficacy Scale (FES) score, which evaluates changes in fear of falls, and gait parameters (velocity, cadence, step length, stride length, and H-H base support) to evaluate gait. After the intervention, Path Length, BBS, TUG, velocity, cadence, step length, and stride length showed significant increases in MITG and TOTG compared to CG (p < 0.05). Post hoc test results showed a significantly greater increase in BBS, TUG, and FES in MITG compared with TOTG and CG (p < 0.05). Our results suggest that motor imagery training combined with functional training has positive effects on balance, gait, and fall efficacy for fall prevention in the elderly.

Effectiveness of Motor Imagery on Motor Recovery in Patients with Multiple Sclerosis: Systematic Review

The effects of motor imagery (MI) on functional recovery of patients with neurological pathologies, such as stroke, has been recently proven. The aim of this study is to evaluate the effectiveness of MI on motor recovery and quality of life (QOL) in patients with multiple sclerosis (pwMS). A search was carried out in the following scientific databases: PubMed, CINAHL, PEDro, Scopus, Cochrane and Web of Science, up to November 2020. The grey literature and reference lists of potentially relevant articles were also searched. The Checklist for Measuring Quality and The Cochrane collaboration’s tool were used to assess the methodological quality and risk of bias of the studies. Five studies were included in the systematic review. Findings showed that pwMS using MI had significant improvements in walking speed and distance, fatigue and QOL. In addition, several benefits were also found in dynamic balance and perceived walking ability. Although the evidence is limited, rehabilitation using MI with the application of musical and verbal guides (compared to non-intervention or other interventions), can produce benefits on gait, fatigue and QOL in pwMS with a low score in the Expanded Disability Status Scale.

Motor imagery for gait rehabilitation after stroke

BACKGROUND

Motor imagery (MI) is defined as a mentally rehearsed task in which movement is imagined but is not performed. The approach includes repetitive imagined body movements or rehearsing imagined acts to improve motor performance.

OBJECTIVES

To assess the treatment effects of MI for enhancing ability to walk among people following stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group registry, CENTRAL, MEDLINE, Embase and seven other databases. We also searched trial registries and reference lists. The last searches were conducted on 24 February 2020.

SELECTION CRITERIA

Randomized controlled trials (RCTs) using MI alone or associated with action observation or physical practice to improve gait in individuals after stroke. The critical outcome was the ability to walk, assessed using either a continuous variable (walking speed) or a dichotomous variable (dependence on personal assistance). Important outcomes included walking endurance, motor function, functional mobility, and adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the trials according to pre-defined inclusion criteria, extracted the data, assessed the risk of bias, and applied the GRADE approach to evaluate the certainty of the evidence. The review authors contacted the study authors for clarification and missing data.

MAIN RESULTS

We included 21 studies, involving a total of 762 participants. Participants were in the acute, subacute, or chronic stages of stroke, and had a mean age ranging from 50 to 78 years. All participants presented at least some gait deficit. All studies compared MI training versus other therapies. Most of the included studies used MI associated with physical practice in the experimental groups. The treatment time for the experimental groups ranged from two to eight weeks. There was a high risk of bias for at least one assessed domain in 20 of the 21 included studies. Regarding our critical outcome, there was very low-certainty evidence that MI was more beneficial for improving gait (walking speed) compared to other therapies at the end of the treatment (pooled standardized mean difference (SMD) 0.44; 95% confidence interval (CI) 0.06 to 0.81; P = 0.02; six studies; 191 participants; I² = 38%). We did not include the outcome of dependence on personal assistance in the meta-analysis, because only one study provided information regarding the number of participants that became dependent or independent after interventions. For our important outcomes, there was very low-certainty evidence that MI was no more beneficial than other interventions for improving motor function (pooled mean difference (MD) 2.24, 95% CI -1.20 to 5.69; P = 0.20; three studies; 130 participants; I² = 87%) and functional mobility at the end of the treatment (pooled SMD 0.55, 95% CI -0.45 to 1.56; P = 0.09; four studies; 116 participants; I² = 64.2%). No adverse events were observed in those studies that reported this outcome (seven studies). We were unable to pool data regarding walking endurance and all other outcomes at follow-up.

AUTHORS' CONCLUSIONS

We found very low-certainty evidence regarding the short-term benefits of MI on walking speed in individuals who have had a stroke, compared to other therapies. Evidence was insufficient to estimate the effect of MI on the dependence on personal assistance and walking endurance. Compared with other therapies, the evidence indicates that MI does not improve motor function and functional mobility after stroke (very low-certainty evidence). Evidence was also insufficient to estimate the effect of MI on gait, motor function, and functional mobility after stroke compared to placebo or no intervention. Motor Imagery and other therapies used for gait rehabilitation after stroke do not appear to cause significant adverse events.

The Vividness of Motor Imagery Is Correlated With Corticospinal Excitability During Combined Motor Imagery and Action Observation

The present study aimed to investigate the relationship between motor imagery (MI) assessment (ability and quality) and neurophysiological assessment [transcranial magnetic stimulation (TMS)-induced motor-evoked potentials (MEPs)] during combined MI and action observation (AO; MI + AO). Sixteen subjects completed an MI task playing the piano with both hands, and neurophysiological assessment was performed during the MI task. The Movement Imagery Questionnaire-Revised was adopted to evaluate MI ability, while the visual analogue scale (VAS) was adopted to evaluate MI quality. A TMS pulse was delivered during the MI task, and MEPs were subsequently recorded in the abductor pollicis brevis (APB). We found a significant positive correlation between the VAS score and the TMS-induced MEPs (ρ = 0.497, p < 0.001). These findings suggest that the VAS score could potentially reflect the corticospinal excitability during MI + AO, particularly in complex MI tasks.

Graded fMRI Neurofeedback Training of Motor Imagery in Middle Cerebral Artery Stroke Patients: A Preregistered Proof-of-Concept Study

Ischemic stroke of the middle cerebral artery (MCA), a major brain vessel that supplies the primary motor and premotor cortex, is one of the most common causes for severe upper limb impairment. Currently available motor rehabilitation training largely lacks satisfying efficacy with over 70% of stroke survivors showing residual upper limb dysfunction. Motor imagery-based functional magnetic resonance imaging neurofeedback (fMRI-NF) has been suggested as a potential therapeutic technique to improve motor impairment in stroke survivors. In this preregistered proof-of-concept study (https://osf.io/y69jc/), we translated graded fMRI-NF training, a new paradigm that we have previously studied in healthy participants, to first-time MCA stroke survivors with residual mild to severe impairment of upper limb motor function. Neurofeedback was provided from the supplementary motor area (SMA) targeting two different neurofeedback target levels (low and high). We hypothesized that MCA stroke survivors will show (1) sustained SMA-region of interest (ROI) activation and (2) a difference in SMA-ROI activation between low and high neurofeedback conditions during graded fMRI-NF training. At the group level, we found only anecdotal evidence for these preregistered hypotheses. At the individual level, we found anecdotal to moderate evidence for the absence of the hypothesized graded effect for most subjects. These null findings are relevant for future attempts to employ fMRI-NF training in stroke survivors. The study introduces a Bayesian sequential sampling plan, which incorporates prior knowledge, yielding higher sensitivity. The sampling plan was preregistered together with a priori hypotheses and all planned analysis before data collection to address potential publication/researcher biases. Unforeseen difficulties in the translation of our paradigm to a clinical setting required some deviations from the preregistered protocol. We explicitly detail these changes, discuss the accompanied additional challenges that can arise in clinical neurofeedback studies, and formulate recommendations for how these can be addressed. Taken together, this work provides new insights about the feasibility of motor imagery-based graded fMRI-NF training in MCA stroke survivors and serves as a first example for comprehensive study preregistration of an (fMRI) neurofeedback experiment.

Effect of Adding Motor Imagery to Task Specific Training on Facilitation of Sit to Stand in Hemiparetic Patients

Background: Motor imagery training is a cognitive process in which an internal representation of a movement is activated in working memory. The movement is mentally rehearsed, without any physical activity. Task-specific training emphasizes the repetitive practice of skilled movement to enhance functional abilities in hemiparesis. Objectives: To investigate whether task specific training preceded by motor imagery or task specific training alone was more effective for facilitating sit to stand in patients with stroke. Methods: Thirty male patients with stroke were selected from the Cairo University Outpatient Clinic; the median age of participants was 54.5 ± 3.51 years and they were divided equally into two groups. Patients in study group A (n = 15) received motor imagery training for 15 minutes followed by task specific training for 45 minutes, as well as a selected physical therapy program 3 times per week for 6 weeks. The control group B (n = 15) received task specific training for 45 minutes, as well as a selected physical therapy program 3 times per week for 6 weeks. The Fugl-Meyer section of the lower extremity (FMA-LE), Timed up and go test (TUG), and Biodex Balance system were assessed before and after treatment. Results: The results were highly significant for all variables including FMA-LE, TUG and Biodex Balance system in favor of the study group, post treatment. (P = 0.0004, P = 0.0001 and P = 0.0001, respectively). Conclusions: Motor imagery training results in greater improvement in sit to stand ability when used in conjunction with task specific training, rather than task specific training alone.

Mental Simulation Practice Has Beneficial Effects on Patients' Physical Function Following Lower Limb Arthroplasty: A Systematic Review and Meta-analysis

OBJECTIVE

To determine the effectiveness of mental simulation practice (MSP) on measures of physical function recovery in patients who have undergone a joint replacement surgery of lower limbs.

DATA SOURCES

A systematic review was conducted using CINAHL, PubMed/MEDLINE, Embase, SPORTDiscus, PEDro, Cochrane Register of Controlled Trials, and Google Scholar from the earliest record until August 16, 2019.

STUDY SELECTION

The following inclusion criteria were used to determine eligibility for studies: (1) randomized and matched controlled trials recruiting men and women who underwent primary unilateral joint arthroplasty; (2) the study examined the effects of MSP intervention on measures of physical function recovery (both performance-based and patient self-reported); and (3) measures of interest were compared between MSP and control groups. A total of 8 papers (7 studies) met the inclusion criteria and were included.

DATA EXTRACTION

Data were extracted by 1 reviewer and checked by a second reviewer, independently.

DATA SYNTHESIS

When compared with standard physical therapy (SPT), MSP showed an effect on physical function in general (effect size [ES], 0.67; 95% confidence interval [CI], 0.38-0.96; n=7), maximal voluntary strength of knee extensor muscles of the affected leg (ES, 1.41; 95% CI, 0.64-2.18; n=2), brisk walking speed (ES, 1.20; 95% CI, 0.58-1.83; n=2), brisk walking speed with dual task (ES, 1.02; 95% CI, 0.41-1.63; n=2), timed up-to go test (ES, 0.96; 95% CI, 0.15-1.77; n=3), and active flexion of the affected leg (ES, 0.70; 95% CI, 0.29-1.11; n=4). Finally, meta-regression analysis revealed that the effects of MSP were significantly predicted only by total number of training sessions per study.

CONCLUSIONS

The present meta-analysis demonstrated that MSP intervention has multiple positive effects on measures of physical function recovery in patients who have undergone total knee or hip replacement surgery in comparison with SPT. Thus, MSP can be applied as an effective complementary therapy to SPT in physical rehabilitation of this specific population, especially in the early postacute and acute phase.

A randomized controlled trial of motor imagery combined with structured progressive circuit class therapy on gait in stroke survivors

Structured Progressive Circuit Class Therapy (SPCCT) was developed based on task-oriented therapy, providing benefits to patients’ motivation and motor function. Training with Motor Imagery (MI) alone can improve gait performance in stroke survivors, but a greater effect may be observed when combined with SPCCT. Health education (HE) is a basic component of stroke rehabilitation and can reduce depression and emotional distress. Thus, this study aimed to investigate the effect of MI with SPCCT against HE with SPCCT on gait in stroke survivors. Two hundred and ninety stroke survivors from 3 hospitals in Yangon, Myanmar enrolled in the study. Of these, 40 stroke survivors who passed the selection criteria were randomized into an experimental (n = 20) or control (n = 20) group. The experimental group received MI training whereas the control group received HE for 25 minutes prior to having the same 65 minutes SPCCT program, with both groups receiving training 3 times a week over 4 weeks. Temporo-spatial gait variables and lower limb muscle strength of the affected side were assessed at baseline, 2 weeks, and 4 weeks after intervention. After 4 weeks of training, the experimental group showed greater improvement than the control group in all temporospatial gait variables, except for the unaffected step length and step time symmetry which showed no difference. In addition, greater improvements of the affected hip flexor and knee extensor muscle strength were found in the experimental group. In conclusion, a combination of MI with SPCCT provided a greater therapeutic effect on gait and lower limb muscle strengths in stroke survivors.

Embodiment Is Related to Better Performance on a Brain-Computer Interface in Immersive Virtual Reality: A Pilot Study

Electroencephalography (EEG)-based brain-computer interfaces (BCIs) for motor rehabilitation aim to "close the loop" between attempted motor commands and sensory feedback by providing supplemental information when individuals successfully achieve specific brain patterns. Existing EEG-based BCIs use various displays to provide feedback, ranging from displays considered more immersive (e.g., head-mounted display virtual reality (HMD-VR)) to displays considered less immersive (e.g., computer screens). However, it is not clear whether more immersive displays improve neurofeedback performance and whether there are individual performance differences in HMD-VR versus screen-based neurofeedback. In this pilot study, we compared neurofeedback performance in HMD-VR versus a computer screen in 12 healthy individuals and examined whether individual differences on two measures (i.e., presence, embodiment) were related to neurofeedback performance in either environment. We found that, while participants' performance on the BCI was similar between display conditions, the participants' reported levels of embodiment were significantly different. Specifically, participants experienced higher levels of embodiment in HMD-VR compared to a computer screen. We further found that reported levels of embodiment positively correlated with neurofeedback performance only in HMD-VR. Overall, these preliminary results suggest that embodiment may relate to better performance on EEG-based BCIs and that HMD-VR may increase embodiment compared to computer screens.

Clinical assessment of motor imagery and physical function in mild stroke patients

[Purpose] The aim of this study was to clarify whether the motor imagery of walking and physical function are related in mild hemiplegic stroke patients. [Participants and Methods] Sixteen mild hemiplegic stroke patients were included in this study. We evaluated motor imagery with a 10-m walking, the estimation error and the kinesthetic and visual imagery questionnaire. Physical function was evaluated with the actual 10-m walk test time, Brunnstrom recovery stage, stroke impairment assessment set, and functional independent measure. The correlation coefficient was calculated using Spearman’s correlation coefficient for all evaluation methods. [Results] The 10-m walking motor imagery took an average of 23.36 ± 22.14 s. The actual 10-m walk test averaged 24.87 ± 21.41 s. The 10-m walking motor imagery and the 10-m walking speed were significantly correlated. There was a significant correlation between the 10-m walking motor imagery and the Brunnstrom recovery stage, stroke impairment assessment set, and functional independent measure. There were no significant correlations between the estimation error and all the assessments. [Conclusion] These results show that the motor imagery of walking is related to physical function in mild hemiplegic stroke patients.

Brain activation induced by different strengths of hand grasp: a functional magnetic resonance imaging study

Mirror neuron system can be activated by observation and execution of an action. It has an important function of action understanding. We investigated brain activations in humans by observing the strength of a hand grasp using functional magnetic resonance imaging. Twenty right-handed healthy individuals, consisting of 10 males and 10 females, aged 22.40 ± 2.04 years, were recruited into this study from September to November 2017 via posters. Light hand grasp task video showed a hand lightly grasping and releasing a ball repeatedly. Powerful hand grasp task video showed a hand tightly grasping and releasing a ball repeatedly. Functional magnetic resonance imaging block design paradigm comprised five stimulation blocks alternating with five baseline blocks. Stimulation blocks were presented with two stimulus tasks, consisting of a light grasp and a powerful grasp. Region of interest was defined around the inferior parietal lobule, inferior frontal gyrus, and superior temporal sulcus which have been called mirror neuron system. The inferior parietal lobule, fusiform, postcentral, occipital, temporal, and frontal gyri were activated during light and powerful grasp tasks. The BOLD signal response of a powerful grasp was stronger than that of a light grasp. These results suggest that brain activation of the inferior parietal lobule, which is the core brain region of the mirror neuron system, was stronger in the powerful grasp task than in the light grasp task. We believe that our results might be helpful for instructing rehabilitation of brain injury. This study was approved by the Institutional Review Board of Daegu Oriental Hospital of Daegu Haany University on September 8, 2017 (approval No. DHUMC-D-17020-PRO-01).

Hypnotic State Modulates Sensorimotor Beta Rhythms During Real Movement and Motor Imagery

Hypnosis techniques are currently used in the medical field and directly influences the patient's state of relaxation, perception of the body, and its visual imagination. There is evidence to suggest that a hypnotic state may help patients to better achieve tasks of motor imagination, which is central in the rehabilitation protocols after a stroke. However, the hypnosis techniques could also alter activity in the motor cortex. To the best of our knowledge, the impact of hypnosis on the EEG signal during a movement or an imagined movement is poorly investigated. In particular, how event-related desynchronization (ERD) and event-related synchronization (ERS) patterns would be modulated for different motor tasks may provide a better understanding of the potential benefits of hypnosis for stroke rehabilitation. To investigate this purpose, we recorded EEG signals from 23 healthy volunteers who performed real movements and motor imageries in a closed eye condition. Our results suggest that the state of hypnosis changes the sensorimotor beta rhythm during the ERD phase but maintains the ERS phase in the mu and beta frequency band, suggesting a different activation of the motor cortex in a hypnotized state.

Imagery Ability and Imagery Perspective Preference: A Study of Their Relationship and Age- and Gender-Related Changes

This study examined if imagery ability (i.e., vividness and temporal congruence between imagined and executed knee extensions) and imagery perspective preference were affected by ageing and gender. Ninety-four participants, 31 young, 43 intermediate, and 20 older adults completed the Vividness of Movement Imagery Questionnaire-2 and a knee extension temporal congruence test to reflect on their imagery ability and an imagery perspective preference test. Male participants had a better imagery ability than the female participants (F (4, 85) = 2.84, p = .029, η² = .118). However, significant age-related changes in imagery ability were not found in the three age groups. Change in imagery perspective preference with a trend towards an external imagery perspective was observed with ageing (F (3, 89) = 3.16, p = .028, η² = .096) but not between male and female. The results suggest that imagery ability may be preserved with ageing. As individuals age, their preference for using an imagery perspective shifts from a more internal to a more external perspective. This understanding is important when designing future imagery research and real-life application or clinical intervention.

Efficacy of motor imagery additional to motor-based therapy in the recovery of motor function of the upper limb in post-stroke individuals: a systematic review

Background. Motor imagery (MI) consists of the mental simulation of repetitive movements with the intention of promoting the learning of a motor skill. It seems to be an additional useful tool for motor-based therapy to potentiate the rehabilitation of the upper limb function of post-stroke individuals. Objective. To investigate whether MI combined with motor-based therapy is effective in recovering motor deficits of upper limbs from post-stroke individuals. Method. A systematic review of the literature was performed in the PEDro, LILACS, Cochrane, SCOPUS, Medline/PubMed and SciELO databases. Randomized controlled trials (RCTs) investigating the efficacy of MI associated with motor-based therapy compared with isolated motor-based therapy were included. The included outcomes were gross motor function and functional activities of the upper limb of post-stroke individuals. The physiotherapy evidence database scale was applied for evaluation of methodological quality. Results. Four RCTs were included, with a total of 104 participants, with methodological quality varying from moderate to high. There was a statistically significant improvement in upper limb motor function in all studies. Gross motor function was higher in MI associated with motor-based therapy compared to controls, but only in one study there was superiority in the results of functional activities of the upper limb. Conclusion. There is evidence showing that MI associated with motor-based therapy is an effective tool in improving the motor function of upper limbs of post-stroke individuals. However, more studies are needed to establish criteria for frequency and duration of intervention, and what better type of MI should be used.

EMG Muscle Activation Pattern of Four Lower Extremity Muscles during Stair Climbing, Motor Imagery, and Robot-Assisted Stepping: A Cross-Sectional Study in Healthy Individuals

BACKGROUND

Stair climbing can be a challenging part of daily life and a limiting factor for social participation, in particular for patients after stroke. In order to promote motor relearning of stair climbing, different therapeutical measures can be applied such as motor imagery and robot-assisted stepping therapy. Both are common therapy measures and a positive influence on the rehabilitation process has been reported. However, there are contradictory results regarding the neuromuscular effect of motor imagery, and the effect of robot-assisted tilt table stepping on the EMG activation compared to stair climbing itself is not known. Thus, we investigated the EMG activity during (1) a stepping task on the robot-assisted tilt table Erigo, (2) motor imagery of stair climbing, and (3) real stair climbing in healthy individuals for a subsequent study on patients with lower limb motor impairment. The aim was to assess potential amplitude independent changes of the EMG activation as a function of the different conditions.

METHODS

EMG data of four muscles of the dominant leg were recorded in m. rectus femoris, m. biceps femoris, m. tibialis anterior, and m. gastrocnemius medialis. The cross-correlation analysis was performed to measure similarity/dissimilarity of the EMG curves.

RESULTS

The data of the study participants revealed high cross-correlation coefficients comparing the EMG activation modulation of stair climbing and robot-assisted tilt table stepping in three muscles except for the m. gastrocnemius medialis. As the EMG activation amplitude did not differ between motor imagery and the resting phase the according EMG data of the motor imagery condition were not subjected to a further analysis.

CONCLUSION

Robot-assisted tilt table stepping, but rather not motor imagery, evokes a similar activation in certain leg muscles compared to real stair climbing.

A systematic review of physical rehabilitation interventions for stroke in low and lower-middle income countries

Purpose: Approximately 70% of strokes occur in low and middle income countries, yet the effectiveness of physical rehabilitation in these contexts remains undetermined. This systematic review identifies and summarises the current evidence supporting physical rehabilitation interventions post-stroke in low and lower-middle income countries.Methods: Five databases were comprehensively searched (April 2017) for randomised controlled trials, clinical controlled trials, and cohort studies testing rehabilitation interventions post-stroke in these countries. The Effective Public Health Practice Project Tool assessed quality of included studies.Results: Sixty-two studies (2115 participants) were included. Interventions addressed upper limb (n = 26), lower limb (n = 22), and other (n = 14) outcomes. Seven studies were rated as strong in quality, 16 moderate and 39 rated as weak. Overall, in addition to usual care, physical rehabilitation interventions improved outcomes for stroke survivors. Best evidence synthesis provides level I (b) evidence supporting constraint induced movement therapy and mirror therapy to improve upper limb functional outcomes. Level I (b) evidence supports multimodal interventions that include lower limb motor imagery to improve gait parameters. Level II (b) evidence supports sit-to-stand training to improve balance outcomes.Conclusions: Exercise-based and brain training interventions improved functional outcomes post-stroke in low and lower-middle income countries. Further high-quality studies including participation outcomes are required.Implications for RehabilitationLow-cost physical rehabilitation interventions requiring minimal resources can improve functional outcomes after stroke in low and lower-middle income countries.Exercise-based interventions can improve upper limb, lower limb, gait, and balance outcomes after stroke.Brain training paradigms such as mirror therapy and motor imagery, when included in therapy packages, can improve upper limb and gait outcomes.The proven efficacy for rehabilitation interventions in improving stroke outcomes in low and lower-middle income countries supports the need to strengthen the rehabilitation workforce in this context.

Effects and Dose-Response Relationships of Motor Imagery Practice on Strength Development in Healthy Adult Populations: a Systematic Review and Meta-analysis

BACKGROUND

Motor imagery (MI), a mental simulation of a movement without overt muscle contraction, has been largely used to improve general motor tasks. However, the effects of MI practice on maximal voluntary strength (MVS) remain equivocal.

OBJECTIVES

The aims of this meta-analysis were to (1) estimate whether MI practice intervention can meaningfully improve MVS in healthy adults; (2) compare the effects of MI practice on MVS with its combination with physical practice (MI-C), and with physical practice (PP) training alone; and (3) investigate the dose-response relationships of MI practice.

DATA SOURCES AND STUDY ELIGIBILITY

Seven electronic databases were searched up to April 2017. Initially 717 studies were identified; however, after evaluation of the study characteristics, data from 13 articles involving 370 participants were extracted. The meta-analysis was completed on MVS as the primary parameter. In addition, parameters associated with training volume, training intensity, and time spent training were used to investigate dose-response relationships.

RESULTS

MI practice moderately improved MVS. When compared to conventional PP, effects were of small benefit in favour of PP. MI-C when compared to PP showed unclear effects. MI practice produced moderate effects in both upper and lower extremities on MVS. The cortical representation area of the involved muscles did not modify the effects. Meta-regression analysis revealed that (a) a training period of 4 weeks, (b) a frequency of three times per week, (c) two to three sets per single session, (d) 25 repetitions per single set, and (e) single session duration of 15 min were associated with enhanced improvements in muscle strength following MI practice. Similar dose-response relationships were observed following MI and PP.

CONCLUSIONS

The present meta-analysis demonstrates that compared to a no-exercise control group of healthy adults, MI practice increases MVS, but less than PP. These findings suggest that MI practice could be considered as a substitute or additional training tool to preserve muscle function when athletes are not exposed to maximal training intensities.

Action dual tasks reveal differential effects of visual imagery perspectives on motor performance

Imagery research has identified two main visual perspectives, external visual imagery (EVI, third person) and internal visual imagery (IVI, first person). Based upon findings from brain imaging literature showing that different neural substrates are recruited for IVI and EVI perspectives, and that IVI activates motor system brain areas, we hypothesised that a concurrent action dual task would cause greater interference in performance for IVI than EVI. In a first experiment, participants were allocated to either an IVI or an EVI group, and were tasked with moving an onscreen marker towards a target in three blocked conditions: imagery, imagery with a concurrent motor dual-task of sequencing, and a math control. An interaction between imagery group and condition was driven by greater root mean square error for participants in the dual-task condition in the IVI group compared with the EVI group. We replicated the experiment with an eye-tracking objective measure of IVI; the results again showed that participants in the IVI group made more errors in motor movements, and an interference effect in eye movements, during the dual-task sequencing condition compared with the EVI group. The results of the two experiments reveal that a secondary motor task does interfere with IVI, providing behavioural evidence that IVI appears to rely on motor system processes more than EVI. These results have important implications for the use of visual imagery perspectives across a number of domains, with this paper being an essential reference for those conducting visual imagery perspectives research.

Neural Mechanisms Involved in Mental Imagery of Slip-Perturbation While Walking: A Preliminary fMRI Study

Background: Behavioral evidence for cortical involvement in reactive balance control in response to environmental perturbation is established, however, the neural correlates are not known. This study aimed to examine the neural mechanisms involved in reactive balance control for recovery from slip-like perturbations using mental imagery and to evaluate the difference in activation patterns between imagined and observed slipping. Methods: Ten healthy young participants after an exposure to regular walking and slip-perturbation trial on a treadmill, performed mental imagery and observation tasks in the MR scanner. Participants received verbal instructions to imagine walking (IW), observe walking (OW), imagine slipping (IS) and observe slipping (OS) while walking. Results: Analysis using general linear model showed increased activation during IS versus IW condition in precentral gyrus, middle frontal gyrus, superior, middle and transverse temporal gyrus, parahippocampal gyrus, cingulate gyrus, insula, pulvinar nucleus of the thalamus, pons, anterior and posterior cerebellar lobes. During IS versus OS condition, there was additional activation in parahippocampus, cingulate gyrus, inferior parietal lobule, superior temporal, middle and inferior frontal gyrus. Conclusion: The findings of the current study support involvement of higher cortical and subcortical structures in reactive balance control. Greater activation during slipping could be attributed to the complexity of the sensorimotor task and increased demands to maintain postural stability during slipping as compared with regular walking. Furthermore, our findings suggest that mental imagery of slipping recruited greater neural substrates rather than observation of slipping, possibly due to increased sensory, cognitive and perceptual processing demands. New and Noteworthy: The behavioral factors contributing to falls from external perturbations while walking are better understood than neural mechanisms underlying the behavioral response. This study examines the neural activation pattern associated with reactive balance control during slip-like perturbations while walking through an fMRI paradigm. This study identified specific neural mechanisms involved in complex postural movements during sudden perturbations, to particularly determine the role of cortical structures in reactive balance control. It further highlights the specific differences in neural structures involved in regular unperturbed versus perturbed walking.

Change in Reciprocal Inhibition of the Forearm with Motor Imagery among Patients with Chronic Stroke

We investigated cortically mediated changes in reciprocal inhibition (RI) following motor imagery (MI) in short- and long(er)-term periods. The goals of this study were (1) to describe RI during MI in patients with chronic stroke and (2) to examine the change in RI after MI-based brain-machine interface (BMI) training. Twenty-four chronic stroke patients participated in study 1. All patients imagined wrist extension on the affected side. RI from the extensor carpi radialis to the flexor carpi radialis (FCR) was assessed using a FCR H reflex conditioning-test paradigm. We calculated the "MI effect score on RI" (RI value during MI divided by that at rest) and compared that score according to lesion location. RI during MI showed a significant enhancement compared with RI at rest. The MI effect score on RI in the subcortical lesion group was significantly greater than that in the cortical lesion group. Eleven stroke patients participated in study 2. All patients performed BMI training for 10 days. The MI effect score on RI at a 20 ms interstimulus interval was significantly increased after BMI compared with baseline. In conclusion, mental practice with MI may induce plastic change in spinal reciprocal inhibitory circuits in patients with stroke.

Can a single session of motor imagery promote motor learning of locomotion in older adults? A randomized controlled trial

Purpose

To investigate the influence of a single session of locomotor-based motor imagery training on motor learning and physical performance.

Patients and methods

Thirty independent adults aged >65 years took part in the randomized controlled trial. The study was conducted within an exercise science laboratory. Participants were randomly divided into three groups following baseline locomotor testing: motor imagery training, physical training, and control groups. The motor imagery training group completed 20 imagined repetitions of a locomotor task, the physical training group completed 20 physical repetitions of a locomotor task, and the control group spent 25 minutes playing mentally stimulating games on an iPad. Imagined and physical performance times were measured for each training repetition. Gait speed (preferred and fast), timed-up-and-go, gait variability and the time to complete an obstacle course were completed before and after the single training session.

Results

Motor learning occurred in both the motor imagery training and physical training groups. Motor imagery training led to refinements in motor planning resulting in imagined movements better matching the physically performed movement at the end of training. Motor imagery and physical training also promoted improvements in some locomotion outcomes as demonstrated by medium to large effect size improvements after training for fast gait speed and timed-up-and-go. There were no training effects on gait variability.

Conclusion

A single session of motor imagery training promoted motor learning of locomotion in independent older adults. Motor imagery training of a specific locomotor task also had a positive transfer effect on related physical locomotor performance outcomes.

Optimal Combination of Anodal Transcranial Direct Current Stimulations and Motor Imagery Interventions

Motor imagery contributes to enhance the (re)learning of motor skills through remapping of cortical networks. Combining motor imagery with anodal transcranial direct-current stimulation (a-tDCS) over the primary motor cortex has further been shown to promote its beneficial effects on postural control. Whether motor imagery should be performed concomitantly to a-tDCS (over depolarized membrane) or consecutively (over changing neurotransmitters activity) remains to be elucidated. In the present study, we measured the performance in a postural control task before and after three experimental conditions. Participants received a-tDCS before (tDCS_Before), during (tDCS_During), or both before and during motor imagery training (tDCS_{Before + During}). Performance was improved after tDCS_During, but not after both the tDCS_Before and tDCS_{Before + During} conditions. These results support that homeostatic plasticity is likely to operate following a-tDCS through decreasing cortical excitability and that motor imagery should be performed during anodal stimulation for optimum gains.

Interventions to Improve Movement and Functional Outcomes in Adult Stroke Rehabilitation: Review and Evidence Summary

Background

Patients who have had a stroke may not be familiar with the terminology nor have the resources to efficiently search for evidence-based rehabilitation therapies to restore movement and functional outcomes. Recognizing that a thorough systematic review on this topic is beyond the scope of this article, we conducted a rapid review evidence summary to determine the level of evidence for common rehabilitation interventions to improve movement/motor and functional outcomes in adults who have had a stroke.

Objective

The objective of this study was to find evidence for common rehabilitation interventions to improve movement/motor and functional outcomes in adults who have had a stroke.

Methods

Medline Complete, PubMed, CINAHL Complete, Cochrane Database, Rehabilitation and Sports Medicine Source, Dissertation Abstracts International, and National Guideline Clearinghouse, from 1996 to April of 2016, were searched. From 348 articles, 173 met the following inclusion criteria: (1) published systematic reviews or meta-analyses, (2) outcomes target functional movement or motor skills of the upper and lower limbs, (3) non-pharmacological interventions that are commonly delivered to post-stroke population (acute and chronic), (4) human studies, and (5) English. Evidence tables were created to analyze the findings of systematic reviews and meta-analyses by category of interventions and outcomes.

Results

This rapid review found that the following interventions possess credible evidence to improve functional movement of persons with stroke: cardiorespiratory training, therapeutic exercise (ie, strengthening), task-oriented training (task-specific training), constraint-induced movement therapy (CIMT), mental practice, and mirror therapy. Neuromuscular electrical stimulation (NMES) (ie, functional electrical stimulation) shows promise as an intervention for stroke survivors.

Conclusions

Most commonly delivered therapeutic interventions to improve motor recovery after a stroke possess moderate quality evidence and are effective. Future research recommendations, such as optimal timing and dosage, would help rehabilitation professionals tailor interventions to achieve the best outcomes for stroke survivors.

Human-to-human closed-loop control based on brain-to-brain interface and muscle-to-muscle interface

Novel communication techniques have always been fascinating for humankind. This pilot study presents an approach to human interaction by combining direct brain-to-brain interface (BBI) and muscle-to-muscle interface (MMI) in a closed-loop pattern. In this system, artificial paths (data flows) functionally connect natural paths (nerves). The intention from one subject (sender) is recognized using electroencephalography (EEG) based brain-computer interface (BCI), which is sent out to trigger transcranial magnetic stimulation (TMS) on the other subject (receiver) and induce hand motion; meanwhile TMS results in a significant change on the motor evoked potentials (MEP) recorded by electromyography (EMG) of the receiver's arm, which triggers functional electrical stimulation (FES) applied to the sender's arm and generates hand motion. Human-controlled loop and automatic control loop experiments were performed with 6 pairs of healthy subjects to evaluate the performance of the introduced mechanism. The results indicated that response accuracy during human-controlled experiments was 85% which demonstrates the feasibility of the proposed method. During the automatic control test, two subjects could accomplish repetitive and reciprocal hand motion control up to 85 times consecutively.

The effect of motor imagery training for trunk movements on trunk muscle control and proprioception in stroke patients

[Purpose] The present study was conducted to evaluate the effect of motor imagery training for trunk movements on trunk muscle control and proprioception in stroke patients. [Subjects and Methods] A total of 12 study subjects were randomly assigned to the experimental group (a motor imagery training group) and the control group (a neurodevelopmental treatment, NDT) group. The two groups were treated five times (30 minutes each time) per week for 4 weeks. The experimental group underwent imagery training for 10 minutes and trunk control centered NDT for 20 minutes and the control group underwent only trunk control centered NDT for 30 minutes. The trunk muscle activity and the position sense of the subjects were evaluated before and after the intervention. [Results] The two groups showed significant improvements in muscle activity after the intervention. Only the experimental group showed significant improvements in proprioception. The experimental group showed significant improvements in the variations of muscle activity and proprioception compared to the control group. [Conclusion] Motor imagery training for trunk movements can be effectively used to improve trunk muscle activity and proprioception in stroke patients.

Motor Imagery-Based Rehabilitation: Potential Neural Correlates and Clinical Application for Functional Recovery of Motor Deficits after Stroke

Motor imagery (MI), defined as the mental implementation of an action in the absence of movement or muscle activation, is a rehabilitation technique that offers a means to replace or restore lost motor function in stroke patients when used in conjunction with conventional physiotherapy procedures. This article briefly reviews the concepts and neural correlates of MI in order to promote improved understanding, as well as to enhance the clinical utility of MI-based rehabilitation regimens. We specifically highlight the role of the cerebellum and basal ganglia, premotor, supplementary motor, and prefrontal areas, primary motor cortex, and parietal cortex. Additionally, we examine the recent literature related to MI and its potential as a therapeutic technique in both upper and lower limb stroke rehabilitation.

Scale-Dependent Signal Identification in Low-Dimensional Subspace: Motor Imagery Task Classification

Motor imagery electroencephalography (EEG) has been successfully used in locomotor rehabilitation programs. While the noise-assisted multivariate empirical mode decomposition (NA-MEMD) algorithm has been utilized to extract task-specific frequency bands from all channels in the same scale as the intrinsic mode functions (IMFs), identifying and extracting the specific IMFs that contain significant information remain difficult. In this paper, a novel method has been developed to identify the information-bearing components in a low-dimensional subspace without prior knowledge. Our method trains a Gaussian mixture model (GMM) of the composite data, which is comprised of the IMFs from both the original signal and noise, by employing kernel spectral regression to reduce the dimension of the composite data. The informative IMFs are then discriminated using a GMM clustering algorithm, the common spatial pattern (CSP) approach is exploited to extract the task-related features from the reconstructed signals, and a support vector machine (SVM) is applied to the extracted features to recognize the classes of EEG signals during different motor imagery tasks. The effectiveness of the proposed method has been verified by both computer simulations and motor imagery EEG datasets.

Motor Imagery Training on Muscle Strength and Gait Performance in Ambulant Stroke Subjects-A Randomized Clinical Trial

INTRODUCTION

The ultimate goal of physiotherapy in stroke rehabilitation is focused towards physical independence and to restore their functional ability during activities of daily living (ADLs). Motor imagery (MI) is an active process during which a specific action is reproduced within working memory without any actual movements. MI training enhances motor learning, neural reorganization and cortical activation in stroke. The efficacy of MI training involving lower extremity mobility tasks need to be assessed.

AIM

To evaluate the effects of combining motor imagery with physical practice in paretic Lower Extremity Muscles Strength and Gait Performance in Ambulant Stroke subjects.

MATERIALS AND METHODS

A Randomized Clinical Trial was conducted in Department of Physical Therapy, Tertiary Care Hospitals, Mangalore, India which includes 40 hemi paretic subjects (>3 months post-stroke) who were ambulant with good imagery ability in both KVIQ-20 ≥ 60 and Time dependent MI screening test were recruited and randomly allocated into task-oriented training group (n=20) and task-oriented training group plus MI group (n=20). Subjects in both groups underwent task orientated training for lower extremity 45-60 minutes, 4 days per week for 3 weeks. In addition, the experimental group received 30 minutes of audio-based lower extremity mobility tasks for MI practice. Isometric muscle strength of Hip, Knee and Ankle using a hand-held dynamometer and self-selected 10 m gait speed were assessed before and after 3 weeks of intervention.

RESULTS

Both the groups had found a significant change for all the outcome measures following 3 weeks of interventions with p <.05. The experimental group had shown a significant improvement in paretic hip muscles (both flexors and extensors), knee extensors and ankle dorsiflexors and gait speed compare to control group with p < .05 between group analyses.

CONCLUSION

Additional task specific MI training improves paretic muscle strength and gait performance in ambulant stroke patients.

Effect of Motor Imagery on the F-Wave Parameters in Hemiparetic Stroke Survivors

Objective

To assess the effect of motor imagery, as a rehabilitation method in stroke, on F-wave parameters that undergo changes during upper motor neuron involvement.

Methods

Twenty-one fully conscious hemiparetic stroke survivors with a completely plegic hand (power 0/5) and a minimum interval of 72 hours since stroke were recruited into this study. The mean F-wave latency, amplitude, and persistence in the median and ulnar nerves were measured in both the affected and non-affected sides at rest and in the paretic hand during a mental task. Comparison was made between data from the affected hand and the non-affected hand as well as between data from the affected hand at baseline and during motor imagery.

Results

Patients had significantly different F-wave persistence between the affected and non-affected sides (paired t-test, p<0.001). Motor imagery could improve F-wave persistence in both the investigated nerves (paired t-test, p=0.01 for ulnar nerve and p<0.001 for median nerve) and F-response amplitude in the median nerve (paired t-test, p=0.01) of the affected limb.

Conclusion

The amplitude and persistence of F-wave were improved during motor imagery, representing F-wave facilitation. This result suggests that motor imagery can restore motor neuron excitability, which is depressed after stroke.