Clinical Assessment of Motor Imagery After Stroke

Motor imagery ability of children with duchenne muscular dystrophy: Reliability and validity of kinesthetic and Visual Imagery Questionnaire-10, and its association with cognitive status

PURPOSE

To investigate validity and reliability of the Kinesthetic and Visual Imagery Questionnaire-10 (KVIQ-10) in children with Duchenne Muscular Dystrophy (DMD), to compare the motor imagery (MI) ability with age-matched controls, and to examine the relationship between MI ability and cognitive status.

METHODS

The research involved 38 children who were diagnosed with DMD, as well as 20 healthy controls aged between 7 and 18 years. The KVIQ-10 was assessed for its test-retest reliability, internal consistency, construct and concurrent validity. The Motor Imagery Questionnaire for Children (MIQ-C) was selected as the gold standard test for concurrent validity. Cognitive function was assessed using the Modified Mini Mental Test (MMMT) and Montreal Cognitive Assessment (MoCA).

RESULTS

KVIQ-10 showed excellent test-retest reliability (ICC>0.90) and high internal consistency (Cronbach's alpha>0.70). A moderate-to-strong association was found between KVIQ-10 and MIQ-C subscales (p < 0.001). KVIQ-10 and MIQ-C subscores were statistically lower in the DMD group (p ≤ 0.05). A correlation was found between MoCA and KVIQ-10 in children with DMD (p ≤ 0.05).

CONCLUSIONS

The KVIQ-10 is a reliable and valid measure to assess the MI ability of children with DMD whose imagery ability was determined to be impaired.

CLINICAL TRIAL REGISTRATION NUMBER AND URL

NCT05559710 (https://classic.

CLINICALTRIALS

gov/ct2/show/NCT05559710?term=NCT05559710&draw=2&rank=1).

Feasibility and efficacy of an early sensory-motor rehabilitation program on hand function in patients with stroke: a pilot, single-subject experimental design

OBJECTIVE

Hand and upper limb functional impairments following stroke lead to limitations in performing activities of daily living. We aimed to investigate feasibility and efficacy of an early sensory-motor rehabilitation program on hand and upper limb function in patients with acute stroke.

DESIGN

A pilot, single-subject experimental, A-B-A study.

SETTING

Stroke unit of an educational hospital and an outpatient occupational therapy clinic.

PARTICIPANTS

A convenience sample including five people with acute stroke.

PROCEDURES

Participants received 3 h of an intensive hand and upper limb sensory and motor rehabilitation program, 5 days per week for 3 months (15-min mental imagery, 15-min action observation, 30-min mirror therapy, 1.5-h constraint-induced movement therapy, and 30-min bilateral arm training). Activities were chosen based on the task-oriented occupational therapy approach.

OUTCOME MEASURES

An assessor blinded to intervention program measured sensory and motor functions using action research arm test, box and block test, Semmes-Weinstein monofilaments, and upper extremity section of Fugl-Meyer assessment.

RESULTS

Assessment data points in intervention and follow-up phases compared to baseline were in higher levels, sloped upwardly, and increased significantly for all participants in all outcome measures.

CONCLUSIONS

The present pilot study showed that a package of nowadays evidence-based rehabilitation methods including mental imagery, action observation, mirror therapy, modified constraint-induced movement therapy, bilateral arm training, and task-oriented occupational therapy approach is able to improve sensory and motor functions of the hand and upper limb in patients with acute stroke.

Action observation plus motor imagery and somatosensory discrimination training are effective non-motor approaches to improve manual dexterity

BACKGROUND

Action observation plus motor imagery (AOMI) and somatosensory discrimination training (SSDT) represent sensory input-based approaches to train the motor system without necessarily asking subjects to perform active movements.

PURPOSE

To investigate AOMI and SSDT effects compared to no intervention on manual dexterity in healthy subjects.

STUDY DESIGN

Randomized controlled study.

METHODS

Sixty healthy right-handed participants were randomized into AOMI, SSDT or Control (CTRL) groups. AOMI observed video-clips including right-hand dexterity tasks and concurrently performed motor imagery, SSDT performed surfaces recognition and 2-point distance discrimination tasks with the right hand, whereas CTRL underwent no intervention. A blinded physiotherapist assessed participants for manual dexterity using the Purdue Pegboard Test (Right hand-R, Left hand-L, Both hands-B, R+L+B and assembly tasks) at baseline (T0) and training end (T1). A mixed-design Analysis of Variance with Time as within-subject factor and Group as between-subject factor was used to investigate between-group differences over time.

RESULTS

A Time by Group interaction and Time effect were found for R task, which increased from T0 to T1 in all groups with very large effect sizes for SSDT (d = 1.8, CI95 2.4-1.0, P < .001) and AOMI (d = 1.7, CI95 2.5-1.0, P < .001) and medium effect size for CTRL (d = 0.6, CI95 1.2-0.2, P < .001). Between-group post-hoc comparison for deltas (T1-T0) showed large effect size (d = 1.0, CI95 1.6-0.3, P = .003) in favor of SSDT and medium effect size (d = 0.7, CI95 1.4-0.1, P = .026) in favor of AOMI compared to CTRL. Time effects were found for L, B, R + L + B and assembly tasks (P < .001).

CONCLUSIONS

AOMI and SSDT induced greater manual dexterity improvements than no intervention. These findings supported the role of visual and somatosensory stimuli in building a motor plan and enhancing the accuracy of hand movements. These non-motor approaches may enhance motor performance in job or hobbies requiring marked manual dexterity.

Leveraging Motor Imagery Rehabilitation for Individuals with Disabilities: A Review

Motor imagery, an intricate cognitive procedure encompassing the mental simulation of motor actions, has surfaced as a potent strategy within the neuro-rehabilitation domain. It presents a non-invasive, economically viable method for facilitating individuals with disabilities in enhancing their motor functionality and regaining self-sufficiency. This manuscript delivers an exhaustive analysis of the significance of motor imagery in augmenting functional rehabilitation for individuals afflicted with physical impairments. It investigates the fundamental mechanisms governing motor imagery, its applications across diverse disability conditions, and the prospective advantages it renders. Moreover, this document addresses the prevailing obstacles and prospective trajectories in this sector, accentuating the necessity for continued investigation and the invention of cutting-edge technologies that optimize the potentiality of motor imagery in aiding disabled persons.

Source-Based EEG Neurofeedback for Sustained Motor Imagery of a Single Leg

The aim of the study was to test the feasibility of visual-neurofeedback-guided motor imagery (MI) of the dominant leg, based on source analysis with real-time sLORETA derived from 44 EEG channels. Ten able-bodied participants took part in two sessions: session 1 sustained MI without feedback and session 2 sustained MI of a single leg with neurofeedback. MI was performed in 20 s on and 20 s off intervals to mimic functional magnetic resonance imaging. Neurofeedback in the form of a cortical slice presenting the motor cortex was provided from a frequency band with the strongest activity during real movements. The sLORETA processing delay was 250 ms. Session 1 resulted in bilateral/contralateral activity in the 8-15 Hz band dominantly over the prefrontal cortex while session 2 resulted in ipsi/bilateral activity over the primary motor cortex, covering similar areas as during motor execution. Different frequency bands and spatial distributions in sessions with and without neurofeedback may reflect different motor strategies, most notably a larger proprioception in session 1 and operant conditioning in session 2. Single-leg MI might be used in the early phases of rehabilitation of stroke patients. Simpler visual feedback and motor cueing rather than sustained MI might further increase the intensity of cortical activation.

Motor imagery training to improve language processing: What are the arguments?

Studies showed that motor expertise was found to induce improvement in language processing. Grounded and situated approaches attributed this effect to an underlying automatic simulation of the motor experience elicited by action words, similar to motor imagery (MI), and suggest shared representations of action conceptualization. Interestingly, recent results also suggest that the mental simulation of action by MI training induces motor-system modifications and improves motor performance. Consequently, we hypothesize that, since MI training can induce motor-system modifications, it could be used to reinforce the functional connections between motor and language system, and could thus lead to improved language performance. Here, we explore these potential interactions by reviewing recent fundamental and clinical literature in the action-language and MI domains. We suggested that exploiting the link between action language and MI could open new avenues for complementary language improvement programs. We summarize the current literature to evaluate the rationale behind this novel training and to explore the mechanisms underlying MI and its impact on language performance.

A Method for Using Video Presentation to Increase Cortical Region Activity during Motor Imagery Tasks in Stroke Patients

Previous studies have reported that stroke patients have difficulty recalling the motor imagery (MI) of a task, also known as MI vividness. Research on combining MI with action observation is gaining importance as a method to improve MI vividness. We enrolled 10 right-handed stroke patients and compared MI vividness and cortical activity under different presentation methods (no inverted image, inverted image of another individual’s hand, and an inverted image of the patient’s nonparalyzed hand) using near-infrared spectroscopy. Images of the nonparalyzed upper limb were inverted to make the paralyzed upper limb appear as if it were moving. Three tasks (non inverted image, AO + MI (other hand), AO + MI (own hand)) were randomly performed on 10 stroke patients. MI vividness was significantly higher when the inverted image of the nonparalyzed upper limb was presented compared to the other conditions (p < 0.01). The activity of the cortical regions was also significantly enhanced (p < 0.01). Our study highlights the potential application of inverted images of a stroke patient’s own nonparalyzed hand in mental practice to promote the motor recovery of stroke patients. This technique achieved higher levels of MI vividness and cortical activity when performing motor tasks.

Relationship between the vividness of motor imagery and physical function in patients with subacute hemiplegic stroke: a cross-sectional preliminary study

PURPOSE

The study aimed to clarify whether the vividness of motor imagery is related to lower limb function and walking ability in patients with hemiplegic stroke.

MATERIALS AND METHODS

The study was a cross-sectional preliminary study. The subjects were 15 patients with hemiplegic stroke. The vividness of motor imagery was assessed using the kinesthetic and visual imagery questionnaire. The kinesthetic imagery (KI) involves the sensation of one's own movement, whereas the visual imagery (VI) involves the imagination of a third-person performing the self-movement. Their physical functions were assessed using the Brunnstrom recovery stage, stroke impairment assessment set, 10-m maximum walking speed test, and functional independence measure. KI and VI were compared using the t test. Correlation analysis was performed between KI or VI and various variables as well as between the motor imagery gap (difference between KI and VI) and various variables.

RESULTS

KI was significantly lower than VI (p < .01). KI was correlated not only with lower limb function (r = 0.68) but also with walking speed (r = -0.64). The motor imagery gap was correlated with hip joint function (r = -0.53).

CONCLUSIONS

KI and motor imagery gap were associated with lower limb function and walking ability.

A method for using video presentation to increase the vividness and activity of cortical regions during motor imagery tasks

In recent years, mental practice (MP) using laterally inverted video of a subject's non-paralyzed upper limb to improve the vividness of presented motor imagery (MI) has been shown to be effective for improving the function of a paralyzed upper limb. However, no studies have yet assessed the activity of cortical regions engaged during MI task performance using inverse video presentations and neurophysiological indicators. This study sought to investigate changes in MI vividness and hemodynamic changes in the cerebral cortex during MI performance under the following three conditions in near-infrared spectroscopy: MI-only without inverse video presentation (MI-only), MI with action observation (AO) of an inverse video presentation of another person's hand (AO + MI (other hand)), and MI with AO of an inverse video presentation of a participant's own hand (AO + MI (own hand)). Participants included 66 healthy right-handed adults (41 men and 25 women; mean age: 26.3 ± 4.3 years). There were 23 patients in the MI-only group (mean age: 26.4 ± 4.1 years), 20 in the AO + MI (other hand) group (mean age: 25.9 ± 5.0 years), and 23 in the AO + MI (own hand) group (mean age: 26.9 ± 4.1 years). The MI task involved transferring 1 cm × 1 cm blocks from one plate to another, once per second, using chopsticks held in the non-dominant hand. Based on a visual analog scale (VAS), MI vividness was significantly higher in the AO + MI (own hand) group than in the MI-only group and the AO + MI (other hand) group. A main effect of condition was revealed in terms of MI vividness, as well as regions of interest (ROIs) in certain brain areas associated with motor processing. The data suggest that inverse video presentation of a person's own hand enhances the MI vividness and increases the activity of motor-related cortical areas during MI. This study was approved by the Institutional Ethics Committee of Nagasaki University Graduate School of Biomedical and Health Sciences (approval No. 18121303) on January 18, 2019.

Interplay between nanomedicine and protein corona

Nanomedicine is recognized as a promising agent for diverse biomedical applications; however, its safety and efficiency in clinical practice remains to be enhanced. A priority issue is the protein corona (PC), which imparts unique biological identities to prototype and determines the actual biological functions in biological fluids. Decades of work has already illuminated abundant considerations that influence the composition of the protein corona. Thereinto, the physical assets of nanomedicines (e.g., size and shape, surface properties, nanomaterials) and the biological environment collectively play fundamental roles in shaping the PC, including the types and quantities of plasma proteins. The properties of nanomedicines are dependent on certain factors. This review aims to explore the applications of nanomedicines by regulating their interplay with PC.

Feasibility of motor imagery and effects of activating and relaxing practice on autonomic functions in healthy young adults: A randomised, controlled, assessor-blinded, pilot trial

Introduction

Motor imagery (MI) is the mental rehearsal of a motor task. Between real and imagined movements, a functional equivalence has been described regarding timing and brain activation. The primary study aim was to investigate the feasibility of MI training focusing on the autonomic function in healthy young people. Further aims were to evaluate participants’ MI abilities and compare preliminary effects of activating and relaxing MI on autonomic function and against controls.

Methods

A single-blinded randomised controlled pilot trial was performed. Participants were randomised to the activating MI (1), relaxing MI (2), or control (3) group. Following a MI familiarisation, they practiced home-based kinaesthetic MI for 17 minutes, 5 times/week for 2 weeks. Participants were called once for support. The primary outcome was the feasibility of a full-scale randomised controlled trial using predefined criteria. Secondary outcomes were participants’ MI ability using the Movement Imagery Questionnaire-Revised, mental chronometry tests, hand laterality judgement and semi-structured interviews, autonomic function.

Results

A total of 35 participants completed the study. The feasibility of a larger study was confirmed, despite 35% attrition related to the COVID-19 pandemic. Excellent MI capabilities were seen in participants, and significant correlations between MI ability measures. Interview results showed that participants accepted or liked both interventions. Seven major themes and insider recommendations for MI interventions emerged. No significant differences and negligible to medium effects were observed in MI ability or autonomic function between baseline and post-intervention measures or between groups.

Conclusions

Results showed that neither activating nor relaxing MI seems to change autonomic function in healthy individuals. Further adequately powered studies are required to answer open questions remaining from this study. Future studies should investigate effects of different MI types over a longer period, to rule out habituation and assess autonomic function at several time points and simultaneously with MI.

Peripheral Electrical Stimulation Modulates Cortical Beta-Band Activity

Low-frequency peripheral electrical stimulation using a matrix electrode (PEMS) modulates spinal nociceptive pathways. However, the effects of this intervention on cortical oscillatory activity have not been assessed yet. The aim of this study was to investigate the effects of low-frequency PEMS (4 Hz) on cortical oscillatory activity in different brain states in healthy pain-free participants. In experiment 1, PEMS was compared to sham stimulation. In experiment 2, motor imagery (MI) was used to modulate the sensorimotor brain state. PEMS was applied either during MI-induced oscillatory desynchronization (concurrent PEMS) or after MI (delayed PEMS) in a cross-over design. For both experiments, PEMS was applied on the left forearm and resting-state electroencephalography (EEG) was recording before and after each stimulation condition. Experiment 1 showed a significant decrease of global resting-state beta power after PEMS compared to sham (p = 0.016), with a median change from baseline of −16% for PEMS and −0.54% for sham. A cluster-based permutation test showed a significant difference in resting-state beta power comparing pre- and post-PEMS (p = 0.018) that was most pronounced over bilateral central and left frontal sensors. Experiment 2 did not identify a significant difference in the change from baseline of global EEG power for concurrent PEMS compared to delayed PEMS. Two cluster-based permutation tests suggested that frontal beta power may be increased following both concurrent and delayed PEMS. This study provides novel evidence for supraspinal effects of low-frequency PEMS and an initial indication that the presence of a cognitive task such as MI may influence the effects of PEMS on beta activity. Chronic pain has been associated with changes in beta activity, in particular an increase of beta power in frontal regions. Thus, brain state-dependent PEMS may offer a novel approach to the treatment of chronic pain. However, further studies are warranted to investigate optimal stimulation conditions to achieve a reduction of pain.

Comparison of cerebral activation between motor execution and motor imagery of self-feeding activity

Motor imagery is defined as an act wherein an individual contemplates a mental action of motor execution without apparent action. Mental practice executed by repetitive motor imagery can improve motor performance without simultaneous sensory input or overt output. We aimed to investigate cerebral hemodynamics during motor imagery and motor execution of a self-feeding activity using chopsticks. This study included 21 healthy right-handed volunteers. The self-feeding activity task comprised either motor imagery or motor execution of eating sliced cucumber pickles with chopsticks to examine eight regions of interest: pre-supplementary motor area, supplementary motor area, bilateral prefrontal cortex, premotor area, and sensorimotor cortex. The mean oxyhemoglobin levels were detected using near-infrared spectroscopy to reflect cerebral activation. The mean oxyhemoglobin levels during motor execution were significantly higher in the left sensorimotor cortex than in the supplementary motor area and the left premotor area. Moreover, significantly higher oxyhemoglobin levels were detected in the supplementary motor area and the left premotor area during motor imagery, compared to motor execution. Supplementary motor area and premotor area had important roles in the motor imagery of self-feeding activity. Moreover, the activation levels of the supplementary motor area and the premotor area during motor execution and motor imagery are likely affected by intentional cognitive processes. Levels of cerebral activation differed in some areas during motor execution and motor imagery of a self-feeding activity. This study was approved by the Ethical Review Committee of Nagasaki University (approval No. 18110801) on December 10, 2018.

Functional magnetic resonance brain imaging of imagined walking to study locomotor function after stroke

OBJECTIVE

Imagined walking has yielded insights into normal locomotor control and could improve understanding of neurologic gait dysfunction. This study evaluated brain activation during imagined walking in chronic stroke.

METHODS

Ten persons with stroke and 10 matched controls completed a walking test battery and a magnetic resonance imaging session including imagined walking and knee extension tasks. Brain activations were compared between tasks and groups. Associations between activations and composite gait score were also calculated, while controlling for lesion load.

RESULTS

Stroke and worse gait score were each associated with lesser overall brain activation during knee extension but greater overall activation during imagined walking. During imagined walking, the stroke group significantly activated the primary motor cortex lower limb region and cerebellar locomotor region. Better walking function was associated with less activation of these regions and greater activation of medial superior frontal gyrus area 9.

CONCLUSIONS

Compared with knee extension, imagined walking was less sensitive to stroke-related deficits in brain activation but better at revealing compensatory changes, some of which could be maladaptive.

SIGNIFICANCE

The identified associations for imagined walking suggest potential neural mechanisms of locomotor adaptation after stroke, which could be useful for future intervention development and prognostication.

Effects of a single mental chronometry training session in subacute stroke patients - a randomized controlled trial

Background

Motor imagery training might be helpful in stroke rehabilitation. This study explored if a single session of motor imagery (MI) training induces performance changes in mental chronometry (MC), motor execution, or changes of motor excitability.

Methods

Subacute stroke patients (n = 33) participated in two training sessions. The order was randomized. One training consisted of a mental chronometry task, the other training was a hand identification task, each lasting 30 min. Before and after the training session, the Box and Block Test (BBT) was fully executed and also performed as a mental version which served as a measure of MC. A subgroup analysis based on the presence of sensory deficits was performed. Patients were allocated to three groups (no sensory deficits, moderate sensory deficits, severe sensory deficits). Motor excitability was measured by transcranial magnetic stimulation (TMS) pre and post training. Amplitudes of motor evoked potentials at rest and during pre-innervation as well as the duration of cortical silent period were measured in the affected and the non-affected hand.

Results

Pre-post differences of MC showed an improved MC after the MI training, whereas MC was worse after the hand identification training. Motor execution of the BBT was significantly improved after mental chronometry training but not after hand identification task training. Patients with severe sensory deficits performed significantly inferior in BBT execution and MC abilities prior to the training session compared to patients without sensory deficits or with moderate sensory deficits. However, pre-post differences of MC were similar in the 3 groups. TMS results were not different between pre and post training but showed significant differences between affected and unaffected side.

Conclusion

Even a single training session can modulate MC abilities and BBT motor execution in a task-specific way. Severe sensory deficits are associated with poorer motor performance and poorer MC ability, but do not have a negative impact on training-associated changes of mental chronometry. Studies with longer treatment periods should explore if the observed changes can further be expanded.

Trial registration

DRKS, DRKS00020355, registered March 9th, 2020, retrospectively registered

Shoulder Flexion Pre-Movement Recognition Through Subject-Specific Brain Regions to Command an Upper Limb Exoskeleton

This work presents two brain-computer interfaces (BCIs) for shoulder pre-movement recognition using: 1) manual strategy for Electroencephalography (EEG) channels selection, and 2) subject-specific channels selection by applying non-negative factorization matrix (NMF). Besides, the proposed BCIs compute spatial features extracted from filtered EEG signals through Riemannian covariance matrices and a linear discriminant analysis (LDA) to discriminate both shoulder pre-movement and rest states. We studied on twenty-one healthy subjects different frequency ranges looking the best frequency band for shoulder pre-movement recognition. As a result, our BCI located automatically EEG channels on the contralateral moved limb, and enhancing the pre-movement recognition (ACC = 71.39 ± 12.68%, κ = 0.43 ± 0.25%). The ability of the proposed BCIs to select specific EEG locations more cortically related to the moved limb could benefit the neuro-rehabilitation process.

Imagining handwriting movements in a usual or unusual position: effect of posture congruency on visual and kinesthetic motor imagery

Motor imagery has been used in training programs to improve the performance of motor skills. Handwriting movement may benefit from motor imagery training. To optimize the efficacy of this kind of training, it is important to identify the factors that facilitate the motor imagery process for handwriting movements. Several studies have shown that motor imagery is more easily achieved when there is maximum compatibility between the actual posture and the imagined movement. We, therefore, examined the effect of posture congruency on visual and kinesthetic motor imagery for handwriting movements. Adult participants had to write and imagine writing a sentence by focusing on the evocation of either the kinesthetic or visual consequences of the motion. Half the participants performed the motor imagery task in a congruent posture (sitting with a hand ready for writing), and half in an incongruent one (standing with arms crossed behind the back and fingers spread wide). The temporal similarity between actual and imagined movement times and the vividness of the motor imagery were evaluated. Results revealed that temporal similarity was stronger in the congruent posture condition than in the incongruent one. Furthermore, in the incongruent posture condition, participants reported greater difficulty forming a precise kinesthetic motor image of themselves writing than a visual image, whereas no difference was observed in the congruent posture condition. Taken together, our results show that postural information is taken into account during the mental simulation of handwriting movements. The implications of these findings for guiding the design of motor imagery training are discussed.

What are the determinants of explicit and implicit motor imagery ability in stroke patients?: a controlled study

Purpose: The purposes of the study were to (a) investigate both explicit and implicit motor imagery ability (MIA) impairment after stroke, (b) examine predictive effects of clinical characteristics for MIA after stroke.Materials and Methods: Forty one patients with stroke (PwS) (mean age 59.41 ± 10.19 years; %41 female) and 36 healthy participants (mean age 62.47 ± 9.29 years; %47 female) completed Chaotic Motor Imagery Assessment-Hand Rotation for implicit MIA and Movement Imagery Questionnaire-3 (MIQ-3) and Box and Block Test (BBT) for explicit MIA. The severity of motor and sensory impairments were determined by the Fugl-Meyer Assessment-Upper Extremity (FMAUE) scores. The Turkish version of Motor Activity Log-28 was used to assess amount of use (AUS) and quality of movement in daily life.Results: Our results indicated that both implicit and explicit MIA (except kinaesthetic imagery of MIQ-3) in PwS were statistically impaired compared to controls (p < 0.05). The sensorimotor impairment level, amount of use and movement quality of the affected upper limb were found to be correlated with MIA in various degrees. Total motor scores in FMAUE and AUS were significant predictors of explicit MIA (p < 0.01). Additionally, explicit MIA scores of stroke subgroups were statistically different between severely and mildly impaired patients, in favour of mildly impaired group (p < 0.05).Conclusion: In conclusion, both motor impairment level and amount of daily use of upper extremity were found to be predictive factors for explicit MIA. Further investigation with brain imaging techniques is needed to explore the validity of these findings in establishing MIA.

Cerebral haemodynamics during motor imagery of self-feeding with chopsticks: differences between dominant and non-dominant hand

Purpose: Motor imagery is defined as a dynamic state during which a subject mentally simulates a given action without overt movements. Our aim was to use near-infrared spectroscopy to investigate differences in cerebral haemodynamics during motor imagery of self-feeding with chopsticks using the dominant or non-dominant hand.Materials and methods: Twenty healthy right-handed people participated in this study. The motor imagery task involved eating sliced cucumber pickles using chopsticks with the dominant (right) or non-dominant (left) hand. Activation of regions of interest (pre-supplementary motor area, supplementary motor area, pre-motor area, pre-frontal cortex, and sensorimotor cortex was assessed.Results: Motor imagery vividness of the dominant hand tended to be significantly higher than that of the non-dominant hand. The time of peak oxygenated haemoglobin was significantly earlier in the right pre-frontal cortex than in the supplementary motor area and left pre-motor area. Haemodynamic correlations were detected in more regions of interest during dominant-hand motor imagery than during non-dominant-hand motor imagery.Conclusions: Haemodynamics might be affected by differences in motor imagery vividness caused by variations in motor manipulation.

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.

Mental Practice Ability Among Stroke Survivors: Investigation of Gender and Age

Background: Mental practice refers to the imaginary representation of a motor action. Mental practice interventions are frequently used among stroke survivors to improve motor function. Individual characteristics that may determine whether a person is able to mentally perform a specific movement have been mainly spared in research.

Aims: The aim of the present study is to examine whether gender and age are related to mental practice ability.

Methods: The study has a cross-sectional design. Data collection was done via self-report questionnaires on mental practice ability, sociodemographic information, and perceived stroke impact. Data analysis was conducted in R using descriptive statistics and regression analysis. N = 44 stroke survivors (M = 65.8 years, SD = 11.4, range 48–88), n = 19 of which were female were recruited in two German neurologic rehabilitation facilities.

Results: Age (β = −0.13, p = 0.057) and gender (β = 0.17, p = 0.260) were not associated with mental practice ability, when controlling for time since stroke and perceived stroke impact (Stroke Impact Scale). Perceived stroke impact was significantly related to mental practice ability (β = 0.44, p = 0.004). Those who reported less stroke impact showed better mental practice ability.

Conclusion: Mental practice ability may be preserved in stroke patients, irrespective of age and gender. We report cross-sectional data on mental practice ability in this study, thus the direction of the relationship between mental practice ability and perceived stroke impact is of interest. Future studies should aim at using a longitudinal design and bigger sample sizes.

Motor Imagery Practice and Increased Tongue Strength: A Case Series Feasibility Report

Purpose The aim of the study was to determine the effects of a 6-week progressive resistance tongue exercise protocol in mental practice form on tongue strength. Investigation begins in typically aging adults, a population susceptible to reduced tongue strength and dysphagia secondary to age-related changes in the swallowing mechanism. It was hypothesized that typically aging adults who perform a 6-week progressive resistance tongue exercise protocol in mental practice form would increase tongue strength. Method A prospective, case series intervention study was used. Six healthy women aged 53-78 years completed a 6-week mental practice tongue resistance exercise program utilizing motor imagery to imagine completion of tongue exercises. The main outcome was mean isometric maximum tongue pressures (tongue strength), which were collected at baseline and Weeks 2, 4, and 6 using the Iowa Oral Performance Instrument ( IOPI Medical, 2013 ). Results By Week 6 of the study, all participants had significantly increased their tongue strength compared to baseline. Conclusions The findings indicate that mental practice using motor imagery for tongue exercise may improve tongue strength in healthy individuals at risk for dysphagia and may thus represent a promising direction warranting further investigation in typically aging individuals and patients with dysphagia and decreased tongue strength.

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.

Motor imagery ability assessments in four disciplines: protocol for a systematic review

INTRODUCTION

Motor imagery (MI) is a very popular and well-accepted technique in different disciplines. Originating from sport and psychology, MI is now also used in the field of medicine and education. Several studies confirmed the benefits of MI to facilitate motor learning and skill acquisition. The findings indicated that individual's MI ability might influence the effectiveness of MI interventions. Over the last two centuries, researchers have developed several assessments to evaluate MI's abstract construct. However, no systematic reviews (SR) exist for MI ability evaluation methods and their measurement properties.

METHODS AND ANALYSIS

The SR will evaluate available MI ability assessments and their psychometric properties in four relevant disciplines: sports, psychology, medicine and education. This involves performing searches in SPORTDiscus, PsycINFO, Cochrane Library, Scopus, Web of Science and ERIC. Working independently, two reviewers will screen articles for selection. Then all raw information will be compiled in an overview table-including the articles' characteristics (eg, a study's setting or the population demographics) and the MI ability assessment (psychometric properties). To evaluate the articles' methodological quality, we will use the COSMIN checklist. Then we will evaluate all the included assessments' quality and perform a best-evidence synthesis. Results of this review will be reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

ETHICS AND DISSEMINATION

The SR is based on published data, and ethical approval is not required. This review will provide information on assessment performance and equipment, as well as its main focus and usefulness. Furthermore, we will present the methodological quality of all the included articles and assess the included instruments' quality. Ultimately, this will act as a valuable resource, providing an overview of MI ability assessments for individual clinical settings, treatment aims, and various populations. The SR's final report will be published in a peer-reviewed journal and presented at relevant conferences.

PROSPERO REGISTRATION NUMBER

CRD42017077004.

A Brazilian-Portuguese version of the Kinesthetic and Visual Motor Imagery Questionnaire

Motor imagery has emerged as a potential rehabilitation tool in stroke. The goals of this study were: 1) to develop a translated and culturally-adapted Brazilian-Portugese version of the Kinesthetic and Visual Motor Imagery Questionnaire (KVIQ20-P); 2) to evaluate the psychometric characteristics of the scale in a group of patients with stroke and in an age-matched control group; 3) to compare the KVIQ20 performance between the two groups. Test-retest, inter-rater reliabilities, and internal consistencies were evaluated in 40 patients with stroke and 31 healthy participants. In the stroke group, ICC confidence intervals showed excellent test-retest and inter-rater reliabilities. Cronbach's alpha also indicated excellent internal consistency. Results for controls were comparable to those obtained in persons with stroke. The excellent psychometric properties of the KVIQ20-P should be considered during the design of studies of motor imagery interventions for stroke rehabilitation.

Effects and mechanisms of differently cued and non-cued motor imagery in people with multiple sclerosis: A randomised controlled trial

BACKGROUND

Walking impairment and fatigue are prevalent symptoms in people with multiple sclerosis (PwMS). Motor imagery (MI) with rhythmic auditory cueing improved walking in PwMS, but so far, the underlying mechanisms are not fully explored.

OBJECTIVE

This study investigated the effects and mechanisms of differently cued and non-cued MI on walking, fatigue and quality of life (QoL) in PwMS.

METHODS

A total of 60 PwMS with mild to moderate disability were randomised to music- and verbally cued MI (MVMI), music-cued MI (MMI) or MI. Participants practised cued or non-cued MI of walking for 17 minutes, six times per week for 4 weeks at home. Primary outcomes were walking speed (timed 25-foot walk) and walking distance (6-minute walk test).

RESULTS

A total of 59 participants completed the study. All interventions induced significant improvements in walking speed and distance, while MVMI was superior. After cued MI, fatigue and QoL significantly improved, with greatest changes seen after MVMI. All participants showed high MI ability. Post-intervention, sensorimotor synchronisation (SMS) was significantly more accurate after cued MI.

CONCLUSION

All interventions significantly improved walking. MVMI was superior in improving walking, fatigue and QoL. Results suggest that MI and SMS were mechanisms of action.

EEG-Based BCI Control Schemes for Lower-Limb Assistive-Robots

Over recent years, brain-computer interface (BCI) has emerged as an alternative communication system between the human brain and an output device. Deciphered intents, after detecting electrical signals from the human scalp, are translated into control commands used to operate external devices, computer displays and virtual objects in the real-time. BCI provides an augmentative communication by creating a muscle-free channel between the brain and the output devices, primarily for subjects having neuromotor disorders, or trauma to nervous system, notably spinal cord injuries (SCI), and subjects with unaffected sensorimotor functions but disarticulated or amputated residual limbs. This review identifies the potentials of electroencephalography (EEG) based BCI applications for locomotion and mobility rehabilitation. Patients could benefit from its advancements such as wearable lower-limb (LL) exoskeletons, orthosis, prosthesis, wheelchairs, and assistive-robot devices. The EEG communication signals employed by the aforementioned applications that also provide feasibility for future development in the field are sensorimotor rhythms (SMR), event-related potentials (ERP) and visual evoked potentials (VEP). The review is an effort to progress the development of user's mental task related to LL for BCI reliability and confidence measures. As a novel contribution, the reviewed BCI control paradigms for wearable LL and assistive-robots are presented by a general control framework fitting in hierarchical layers. It reflects informatic interactions, between the user, the BCI operator, the shared controller, the robotic device and the environment. Each sub layer of the BCI operator is discussed in detail, highlighting the feature extraction, classification and execution methods employed by the various systems. All applications' key features and their interaction with the environment are reviewed for the EEG-based activity mode recognition, and presented in form of a table. It is suggested to structure EEG-BCI controlled LL assistive devices within the presented framework, for future generation of intent-based multifunctional controllers. Despite the development of controllers, for BCI-based wearable or assistive devices that can seamlessly integrate user intent, practical challenges associated with such systems exist and have been discerned, which can be constructive for future developments in the field.

Reliability and Validity of the Japanese Version of the Kinesthetic and Visual Imagery Questionnaire (KVIQ)

In this study, we aimed to (1) translate the English version of the Kinesthetic and Visual Imagery Questionnaire (KVIQ), which assesses motor imagery ability, into Japanese, and (2) investigate the reliability and validity of the Japanese KVIQ. We enrolled 28 healthy adults in this study. We used Cronbach’s alpha coefficients to assess reliability reflected by the internal consistency. Additionally, we assessed validity reflected by the criterion-related validity between the Japanese KVIQ and the Japanese version of the Movement Imagery Questionnaire-Revised (MIQ-R) with Spearman’s rank correlation coefficients. The Cronbach’s alpha coefficients for the KVIQ-20 were 0.88 (Visual) and 0.91 (Kinesthetic), which indicates high reliability. There was a significant positive correlation between the Japanese KVIQ-20 (Total) and the Japanese MIQ-R (Total) (r = 0.86, p < 0.01). Our results suggest that the Japanese KVIQ is an assessment that is a reliable and valid index of motor imagery ability.

Exploring cued and non-cued motor imagery interventions in people with multiple sclerosis: a randomised feasibility trial and reliability study

Background

Motor imagery (MI) is increasingly used in neurorehabilitation to facilitate motor performance. Our previous study results demonstrated significantly improved walking after rhythmic-cued MI in people with multiple sclerosis (pwMS). The present feasibility study was aimed to obtain preliminary information of changes in walking, fatigue, quality of life (QoL) and MI ability following cued and non-cued MI in pwMS. The study further investigated the feasibility of a larger study and examined the reliability of a two-dimensional gait analysis system.

Methods

At the MS-Clinic, Department of Neurology, Medical University of Innsbruck, Austria, 15 adult pwMS (1.5–4.5 on the Expanded Disability Status Scale, 13 females) were randomised to one of three groups: 24 sessions of 17 min of MI with music and verbal cueing (MVMI), with music alone (MMI), or non-cued (MI). Descriptive statistics were reported for all outcomes. Primary outcomes were walking speed (Timed 25-Foot Walk) and walking distance (6-Minute Walk Test). Secondary outcomes were recruitment rate, retention, adherence, acceptability, adverse events, MI ability (Kinaesthetic and Visual Imagery Questionnaire, Time-Dependent MI test), fatigue (Modified Fatigue Impact Scale) and QoL (Multiple Sclerosis Impact Scale-29). The reliability of a gait analysis system used to assess gait synchronisation with music beat was tested.

Results

Participants showed adequate MI abilities. Post-intervention, improvements in walking speed, walking distance, fatigue, QoL and MI ability were observed in all groups. Success of the feasibility criteria was demonstrated by recruitment and retention rates of 8.6% (95% confidence interval, CI 5.2, 13.8%) and 100% (95% CI 76.4, 100%), which exceeded the target rates of 5.7% and 80%. Additionally, the 83% (95% CI 0.42, 0.99) adherence rate surpassed the 67% target rate. Intra-rater reliability analysis of the gait measurement instruments demonstrated excellent Intra-Class Correlation coefficients for step length of 0.978 (95% CI 0.973, 0.982) and step time of 0.880 (95% CI 0.855, 0.902).

Conclusion

Results from our study suggest that cued and non-cued MI are valuable interventions in pwMS who were able to imagine movements. A larger study appears feasible, however, substantial improvements to the methods are required such as stratified randomisation using a computer-generated sequence and blinding of the assessors.

Trial registration

ISRCTN ISRCTN92351899. Registered 10 December 2015.

Electronic supplementary material

The online version of this article (10.1186/s40945-018-0045-0) contains supplementary material, which is available to authorized users.

Prática mental após fisioterapia mantém mobilidade funcional de pessoas com doença de Parkinson

RESUMO O objetivo deste estudo foi avaliar a prática mental após a fisioterapia motora para manutenção dos efeitos obtidos na mobilidade funcional de pessoas com doença de Parkinson (DP). Este ensaio clínico randomizado controlado, com cegamento simples, incluiu 14 sujeitos com DP nos estágios de 1 a 3 (escala de Hoehn & Yahr), com idade entre 45 e 72 anos. Após a avaliação inicial com o Timed Up & Go (TUG), Dynamic Gait Index (DGI) e Falls Efficacy Scale - International Brazil (FES-I Brasil), os sujeitos realizaram 15 sessões de fisioterapia motora. Foram reavaliados e divididos randomicamente em Grupo Controle (GC) e Grupo Prática Mental (GPM). Após a alocação, o GPM foi submetido a 10 sessões de prática mental associada a orientações de exercícios domiciliares. O GC foi orientado apenas a realizar os exercícios domiciliares. Em seguida, os grupos foram novamente reavaliados. Verificou-se que o GPM continuou apresentando redução na média de tempo do TUG na segunda reavaliação (p=0,05). Na segunda reavaliação do DGI, o GPM manteve a mesma média de escore da primeira reavaliação e o GC apresentou declínio da média. Não foram verificadas diferenças significativas na comparação intergrupos dos escores na FES-I Brasil. A prática mental foi capaz de manter os ganhos obtidos pela fisioterapia na mobilidade funcional de pacientes com DP.

Modulating hemispheric lateralization by brain stimulation yields gain in mental and physical activity

Imagery plays an important role in our life. Motor imagery is the mental simulation of a motor act without overt motor output. Previous studies have documented the effect of motor imagery practice. However, its translational potential for patients as well as for athletes, musicians and other groups, depends largely on the transfer from mental practice to overt physical performance. We used bilateral transcranial direct current stimulation (tDCS) over sensorimotor areas to modulate neural lateralization patterns induced by unilateral mental motor imagery and the performance of a physical motor task. Twenty-six healthy older adults participated (mean age = 67.1 years) in a double-blind cross-over sham-controlled study. We found stimulation-related changes at the neural and behavioural level, which were polarity-dependent. Specifically, for the hand contralateral to the anode, electroencephalographic activity induced by motor imagery was more lateralized and motor performance improved. In contrast, for the hand contralateral to the cathode, hemispheric lateralization was reduced. The stimulation-related increase and decrease in neural lateralization were negatively related. Further, the degree of stimulation-related change in neural lateralization correlated with the stimulation-related change on behavioural level. These convergent neurophysiological and behavioural effects underline the potential of tDCS to improve mental and physical motor performance.

A neurocognitive approach for recovering upper extremity movement following subacute stroke: a randomized controlled pilot study

[Purpose] This study aims to describe a protocol based on neurocognitive therapeutic exercises and determine its feasibility and usefulness for upper extremity functionality when compared with a conventional protocol. [Subjects and Methods] Eight subacute stroke patients were randomly assigned to a conventional (control group) or neurocognitive (experimental group) treatment protocol. Both lasted 30 minutes, 3 times a week for 10 weeks and assessments were blinded. Outcome measures included: Motor Evaluation Scale for Upper Extremity in Stroke Patients, Motricity Index, Revised Nottingham Sensory Assessment and Kinesthetic and Visual Imagery Questionnaire. Descriptive measures and nonparametric statistical tests were used for analysis. [Results] The results indicate a more favorable clinical progression in the neurocognitive group regarding upper extremity functional capacity with achievement of the minimal detectable change. The functionality results are related with improvements on muscle strength and sensory discrimination (tactile and kinesthetic). [Conclusion] Despite not showing significant group differences between pre and post-treatment, the neurocognitive approach could be a safe and useful strategy for recovering upper extremity movement following stroke, especially regarding affected hands, with better and longer lasting results. Although this work shows this protocol's feasibility with the panel of scales proposed, larger studies are required to demonstrate its effectiveness.

Electroencephalographic Motor Imagery Brain Connectivity Analysis for BCI: A Review

Recent research has reached a consensus on the feasibility of motor imagery brain-computer interface (MI-BCI) for different applications, especially in stroke rehabilitation. Most MI-BCI systems rely on temporal, spectral, and spatial features of single channels to distinguish different MI patterns. However, no successful communication has been established for a completely locked-in subject. To provide more useful and informative features, it has been recommended to take into account the relationships among electroencephalographic (EEG) sensor/source signals in the form of brain connectivity as an efficient tool of neuroscience. In this review, we briefly report the challenges and limitations of conventional MI-BCIs. Brain connectivity analysis, particularly functional and effective, has been described as one of the most promising approaches for improving MI-BCI performance. An extensive literature on EEG-based MI brain connectivity analysis of healthy subjects is reviewed. We subsequently discuss the brain connectomes during left and right hand, feet, and tongue MI movements. Moreover, key components involved in brain connectivity analysis that considerably affect the results are explained. Finally, possible technical shortcomings that may have influenced the results in previous research are addressed and suggestions are provided.

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.

Damage to Fronto-Parietal Networks Impairs Motor Imagery Ability after Stroke: A Voxel-Based Lesion Symptom Mapping Study

Background: Mental practice with motor imagery has been shown to promote motor skill acquisition in healthy subjects and patients. Although lesions of the common motor imagery and motor execution neural network are expected to impair motor imagery ability, functional equivalence appears to be at least partially preserved in stroke patients.

Aim: To identify brain regions that are mandatory for preserved motor imagery ability after stroke.

Method:Thirty-seven patients with hemiplegia after a first time stroke participated. Motor imagery ability was measured using a Motor Imagery questionnaire and temporal congruence test. A voxelwise lesion symptom mapping approach was used to identify neural correlates of motor imagery in this cohort within the first year post-stroke.

Results: Poor motor imagery vividness was associated with lesions in the left putamen, left ventral premotor cortex and long association fibers linking parieto-occipital regions with the dorsolateral premotor and prefrontal areas. Poor temporal congruence was otherwise linked to lesions in the more rostrally located white matter of the superior corona radiata.

Conclusion: This voxel-based lesion symptom mapping study confirms the association between white matter tract lesions and impaired motor imagery ability, thus emphasizing the importance of an intact fronto-parietal network for motor imagery. Our results further highlight the crucial role of the basal ganglia and premotor cortex when performing motor imagery tasks.

What Do Eye Gaze Metrics Tell Us about Motor Imagery?

Many of the brain structures involved in performing real movements also have increased activity during imagined movements or during motor observation, and this could be the neural substrate underlying the effects of motor imagery in motor learning or motor rehabilitation. In the absence of any objective physiological method of measurement, it is currently impossible to be sure that the patient is indeed performing the task as instructed. Eye gaze recording during a motor imagery task could be a possible way to "spy" on the activity an individual is really engaged in. The aim of the present study was to compare the pattern of eye movement metrics during motor observation, visual and kinesthetic motor imagery (VI, KI), target fixation, and mental calculation. Twenty-two healthy subjects (16 females and 6 males), were required to perform tests in five conditions using imagery in the Box and Block Test tasks following the procedure described by Liepert et al. Eye movements were analysed by a non-invasive oculometric measure (SMI RED250 system). Two parameters describing gaze pattern were calculated: the index of ocular mobility (saccade duration over saccade + fixation duration) and the number of midline crossings (i.e. the number of times the subjects gaze crossed the midline of the screen when performing the different tasks). Both parameters were significantly different between visual imagery and kinesthesic imagery, visual imagery and mental calculation, and visual imagery and target fixation. For the first time we were able to show that eye movement patterns are different during VI and KI tasks. Our results suggest gaze metric parameters could be used as an objective unobtrusive approach to assess engagement in a motor imagery task. Further studies should define how oculomotor parameters could be used as an indicator of the rehabilitation task a patient is engaged in.

Specific Brain Lesions Impair Explicit Motor Imagery Ability: A Systematic Review of the Evidence

OBJECTIVE

To determine which neurologic disorders/lesions impair or restrict motor imagery (MI) ability.

DATA SOURCES

CINAHL, Cochrane, Embase, MEDLINE, Web of Science, PsychINFO, Physiotherapy Evidence Database, and Grey Literature were searched between May 8 and May 14, 2014. Keywords and Medical Subject Headings from 2 concepts (MI and lesion) were exploded to include related search terms (eg, mental practice/mental imagery, neurologic damage/lesion).

STUDY SELECTION

Two independent reviewers assessed the 3861 studies that resulted from the database search. The studies were assessed for relevancy using the following inclusion criteria: use of explicit kinesthetic MI; neurologic lesion location identified; and use of an MI ability assessment tool.

DATA EXTRACTION

Twenty-three studies encompassing 196 participants were included. The 23 studies used 8 different methods for assessing MI ability. MI assessment scores were then normalized to facilitate comparison across studies.

DATA SYNTHESIS

Lesion locations comprised many brain areas, including cortical (eg, parietal and frontal lobes), subcortical (eg, basal ganglia, thalamus), and cerebellum. Lesion etiology primarily was comprised of stroke and Parkinson disease. Several participants presented with lesions resulting from other pathologies. Subjects with parietal lobe damage were most impaired on their ability to perform MI. Subjects with frontal lobe and basal ganglia damage also consistently showed impairment in MI ability.

CONCLUSIONS

Subjects with damage to specific brain structures, including the parietal and frontal lobes, showed impaired MI ability. As such, MI-based neurorehabilitation may not be efficacious in all patient populations. Therefore, decisions related to the use of MI in neurorehabilitation should, in part, be based on the patient's underlying pathophysiology.

Assessing motor imagery ability in younger and older adults by combining measures of vividness, controllability and timing of motor imagery

With the population aging, a large number of patients undergoing rehabilitation are older than 60 years. Also, since the use of motor imagery (MI) training in rehabilitation is becoming more popular, it is important to gain a better knowledge about the age-related changes in MI ability. The main goal of this study was to compare MI ability in younger and older adults as well as to propose a new procedure for testing this ability. Thirty healthy young subjects (mean age: 22.9±2.7 years) and 28 healthy elderly subjects (mean age: 72.4±5.5 years) participated in the experiment. They were administered three tests aimed at assessing three dimensions of MI: (1) the kinesthetic and visual imagery questionnaire (KVIQ) to assess MI vividness; (2) a finger-thumb opposition task to assess MI controllability; and (3) a chronometric task to assess the timing of MI. On average, the younger and older groups showed similar results on the KVIQ and the chronometric task, but the younger group was more accurate at the finger-thumb opposition task. Interestingly, there was a large variability in the performance within both groups, emphasizing the importance of considering each person individually regarding MI ability, whatever his age. Finally, we propose two indexes of MI ability to identify the potential of persons to engage in MI training programs. Future studies are needed to confirm the predictive value of these MI indexes and define inclusion/exclusion thresholds for their use as a screening tool in both younger and older adults.

The embodied nature of motor imagery processes highlighted by short-term limb immobilization

We investigated the embodied nature of motor imagery processes through a recent use-dependent plasticity approach, a short-term limb immobilization paradigm. A splint placed on the participants' left-hand during a brief period of 24 h was used for immobilization. The immobilized participants performed two mental rotation tasks (a hand mental rotation task and a number mental rotation task) before (pre-test) and immediately after (post-test) the splint removal. The control group did not undergo the immobilization procedure. The main results showed an immobilization-induced effect on left-hand stimuli, resulting in a lack of task-repetition benefit. By contrast, accuracy was higher and response times were shorter for right-hand stimuli. No immobilization-induced effects appeared for number stimuli. These results revealed that the cognitive representation of hand movements can be modified by a brief period of sensorimotor deprivation, supporting the hypothesis of the embodied nature of motor simulation processes.

Wireless EEG with individualized channel layout enables efficient motor imagery training

OBJECTIVE

The study compared two channel-reduction approaches in order to investigate the effects of systematic motor imagery (MI) neurofeedback practice in an everyday environment using a very user-friendly EEG system consisting of individualized caps and highly portable hardware.

METHODS

Sixteen BCI novices were trained over four consecutive days to imagine left and right hand movements while receiving feedback. The most informative bipolar channels for use on the subsequent days were identified on the first day for each individual based on a high-density online MI recording.

RESULTS

Online classification accuracy on the first day was 85.1% on average (range: 64.7-97.7%). Offline an individually-selected bipolar channel pair based on common spatial patterns significantly outperformed a pair informed by independent component analysis and a standard 10-20 pair. From day 2 to day 4 online MI accuracy increased significantly (day 2: 69.1%; day 4: 73.3%), which was mostly caused by a reduction in ipsilateral event-related desynchronization of sensorimotor rhythms.

CONCLUSION

The present study demonstrates that systematic MI practice in an everyday environment with a user-friendly EEG system results in MI learning effects.

SIGNIFICANCE

These findings help to bridge the gap between elaborate laboratory studies with healthy participants and efficient home or hospital based MI neurofeedback protocols.

Effects of levodopa on vividness of motor imagery in Parkinson disease

INTRODUCTION

Motor imagery during functional magnetic resonance imaging is commonly used to understand the neural underpinnings of complex movements. This approach has recently been applied to individuals with Parkinson disease (PD) to better understand how brain function may relate to movement dysfunction. However, the ability of individuals with PD to imagine movements when "Off" dopamine replacement medication is poorly understood. Therefore, the primary purpose of the current study is to test the ability of people with PD to imagine movements while "On" and "Off" anti-Parkinson medication.

METHODS

Vividness of imagery was assessed in 28 individuals with mild to moderate PD (Hoehn and Yahr stages 1-3) via the Kinesthetic Visual Imagery Questionnaire (KVIQ-20) both "On" and "Off" anti-Parkinson medication. Vividness of imagery of 32 age-matched older adults was also assessed.

RESULTS

No differences in vividness of imagery were observed between "Off" and "On" medication states (p = 0.15). Imagery was similar between controls and PD both "Off" (p = 0.25) and "On" (p = 0.46) anti-Parkinson medication. A significant correlation was observed between imagery and disease severity while "On" anti-Parkinson medication (r = -0.49; p = 0.008).

DISCUSSION AND CONCLUSIONS

Vividness of movement imagery was not different between "Off" and "On" anti-Parkinson medications or between PD and controls. These results suggest that people with PD are able to imagine similarly to older adults both when "On" and "Off" anti-Parkinson medication, and supports the use of motor imagery in the "Off" medication state.

The therapeutic role of motor imagery on the functional rehabilitation of a stage II shoulder impingement syndrome

PURPOSE

Motor imagery (MI) has been used as a complementary therapeutic tool for motor recovery after central nervous system disease and peripheral injuries. However, it has never been used as a preventive tool. We investigated the use of MI in the rehabilitation of stage II shoulder impingement syndrome. For the first time, MI is used before surgery.

METHOD

Sixteen participants were randomly assigned to either a MI or control group. Shoulder functional assessment (Constant score), range of motion and pain were measured before and after intervention.

RESULTS

Higher Constant score was observed in the MI than in the control group (p=0.04). Participants in the MI group further displayed greater movement amplitude (extension (p<0.001); flexion (p=0.025); lateral rotation (p<0.001). Finally, the MI group showed greater pain decrease (p=0.01).

CONCLUSION

MI intervention seems to alleviate pain and enhance mobility, this is probably due to changes in muscle control and consequently in joint amplitude. MI might contribute to postpone or even protect from passing to stage III that may require surgery. Implications for Rehabilitation Adding motor imagery training to classical physical therapy in a stage II impingement syndrome: Helps in alleviating pain Enhances shoulder mobility Motor imagery is a valuable technique that can be used as a preventive tool before the stage III of the impingement syndrome.

Lower Limb Movement Preparation in Chronic Stroke: A Pilot Study Toward an fNIRS-BCI for Gait Rehabilitation

Background Thus far, most of the brain-computer interfaces (BCIs) developed for motor rehabilitation used electroencephalographic signals to drive prostheses that support upper limb movement. Only few BCIs used hemodynamic signals or were designed to control lower extremity prostheses. Recent technological developments indicate that functional near-infrared spectroscopy (fNIRS)-BCI can be exploited in rehabilitation of lower limb movement due to its great usability and reduced sensitivity to head motion artifacts. Objective The aim of this proof of concept study was to assess whether hemodynamic signals underlying lower limb motor preparation in stroke patients can be reliably measured and classified. Methods fNIRS data were acquired during preparation of left and right hip movement in 7 chronic stroke patients. Results Single-trial analysis indicated that specific hemodynamic changes associated with left and right hip movement preparation can be measured with fNIRS. Linear discriminant analysis classification of totHB signal changes in the premotor cortex and/or posterior parietal cortex indicated above chance accuracy in discriminating paretic from nonparetic movement preparation trials in most of the tested patients. Conclusion The results provide first evidence that fNIRS can detect brain activity associated with single-trial lower limb motor preparation in stroke patients. These findings encourage further investigation of fNIRS suitability for BCI applications in rehabilitation of patients with lower limb motor impairment after stroke.

The perception of peripersonal space in right and left brain damage hemiplegic patients

Peripersonal space, as opposed to extrapersonal space, is the space that contains reachable objects and in which multisensory and sensorimotor integration is enhanced. Thus, the perception of peripersonal space requires combining information on the spatial properties of the environment with information on the current capacity to act. In support of this, recent studies have provided converging evidences that perceiving objects in peripersonal space activates a neural network overlapping with that subtending voluntary motor action and motor imagery. Other studies have also underlined the dominant role of the right hemisphere (RH) in motor planning and of the left hemisphere (LH) in on-line motor guiding, respectively. In the present study, we investigated the effect of a right or left hemiplegia in the perception of peripersonal space. 16 hemiplegic patients with brain damage to the left (LH) or right (RH) hemisphere and eight matched healthy controls performed a color discrimination, a motor imagery and a reachability judgment task. Analyses of response times and accuracy revealed no variation among the three groups in the color discrimination task, suggesting the absence of any specific perceptual or decisional deficits in the patient groups. In contrast, the patient groups revealed longer response times in the motor imagery task when performed in reference to the hemiplegic arm (RH and LH) or to the healthy arm (RH). Moreover, RH group showed longer response times in the reachability judgment task, but only for stimuli located at the boundary of peripersonal space, which was furthermore significantly reduced in size. Considered together, these results confirm the crucial role of the motor system in motor imagery task and the perception of peripersonal space. They also revealed that RH damage has a more detrimental effect on reachability estimates, suggesting that motor planning processes contribute specifically to the perception of peripersonal space.