Imaging motor imagery: methodological issues related to expertise

Characteristic brain functional activation and connectivity during actual and imaginary right-handed grasp

We used 34-channel functional near infrared spectroscopy to investigate and compare changes in oxyhemoglobin concentration of brain networks in bilateral prefrontal cortex, sensorimotor cortex, and occipital lobe of 22 right-handed healthy adults during executive right-handed grasp (motor execution task) and imagined right-handed grasp (motor imagery task). Then calculated lateral index and functional contribution degree, and measured functional connectivity strength between the regions of interest. In the motor executive block task, there was a significant increase in oxyhemoglobin concentration in regions of interest except for right occipital lobe (P<0.05), while in the motor imagery task, all left regions of interest's oxyhemoglobin concentration increased significantly (P<0.05). Except the prefrontal cortex in motor executive task, the left side of the brain was dominant. Left sensorimotor cortex played a major role in these two tasks, followed by right sensorimotor cortex. Among all functional contribution degree, left sensorimotor cortex, right sensorimotor cortex and left occipital lobe ranked top three during these tasks. In continuous acquisition tasks, functional connectivity on during motor imagery task was stronger than that during motor executive task. Brain functions during two tasks of right-hand grasping movement were partially consistent. However, the excitability of brain during motor imagery was lower, and it was more dependent on the participation of left prefrontal cortex, and its synchronous activity of the whole brain was stronger. The trend of functional contribution degree was basically consistent with oxyhemoglobin concentration and lateral index, and can be used as a novel index to evaluate brain function. [ChiCTR2200063792 (2022-09-16)].

Psychophysiological strategies for enhancing performance through imagery-skin conductance level analysis in guided vs. self-produced imagery

Athletes need to achieve their optimal level of arousal for peak performance. Visualization or mental rehearsal (i.e., Imagery) often helps to obtain an appropriate level of activation, which can be detected by monitoring Skin Conductance Level (SCL). However, different types of imagery could elicit different amount of physiological arousal. Therefore, this study aims: (1) to investigate differences in SCL associated with two instructional modalities of imagery (guided vs. self-produced) and six different scripts; (2) to check if SCL could differentiate respondents according to their sport expertise. Thirty participants, aged between 14 and 42 years (M = 22.93; SD = 5.24), with different sport levels took part in the study. Participants listened to each previously recorded script and then were asked to imagine the scene for a minute. During the task, SCL was monitored. We analysed the mean value, variance, slope and number of fluctuations per minute of the electrodermal signal. Unsupervised machine learning models were used for measuring the resemblance of the signal. The Wilcoxon signed-rank test was used for distinguishing guided and self-produced imagery, and The Mann-Whitney U test was used for distinguishing results of different level athletes. We discovered that among others, self-produced imagery generates lower SCL, higher variance, and a higher number of fluctuations compared to guided imagery. Moreover, we found similarities of the SCL signal among the groups of athletes (i.e. expertise level). From a practical point of view, our findings suggest that different imagery instructional modalities can be implemented for specific purposes of mental preparation.

More implicit and more explicit motor imagery tasks for exploring the mental representation of hands and feet in action

The mental representation of the body in action can be explored using motor imagery (MI) tasks. MI tasks can be allocated along a continuum going from more implicit to more explicit tasks, where the discriminant is the degree of action monitoring required to solve the tasks (which is the awareness of using the mental representation of our own body to monitor our motor imagery). Tasks based on laterality judgments, such as the Hand Laterality Task (HLT) and the Foot Laterality Task (FLT), provide an example of more implicit tasks (i.e., less action monitoring is required). While, an example of a more explicit task is the Mental Motor Chronometry task (MMC) for hands and feet, where individuals are asked to perform or imagine performing movements with their limbs (i.e., more action monitoring is required). In our study, we directly compared hands and feet at all these tasks for the first time, as these body districts have different physical features as well as functions. Fifty-five participants were asked to complete an online version of the HLT and FLT (more implicit measure), and an online version of the MMC task for hands and feet (more explicit measure). The mental representation of hands and feet in action differed only when the degree of action monitoring decreased (HLT ≠ FLT); we observed the presence of biomechanical constraints only for hands. Differently, when the degree of action monitoring increased hands and feet did not show any difference (MMC hands = MMC feet). Our results show the presence of a difference in the mental representation of hands and feet in action that specifically depends on the degree of action monitoring.

How Posture and Previous Sensorimotor Experience Influence Muscle Activity during Gait Imagery in Young Healthy Individuals

This study explores how gait imagery (GI) influences lower-limb muscle activity with respect to posture and previous walking experience. We utilized surface electromyography (sEMG) in 36 healthy young individuals aged 24 (±1.1) years to identify muscle activity during a non-gait imagery task (non-GI), as well as GI tasks before (GI-1) and after the execution of walking (GI-2), with assessments performed in both sitting and standing postures. The sEMG was recorded on both lower limbs on the tibialis anterior (TA) and on the gastrocnemius medialis (GM) for all tested tasks. As a result, a significant muscle activity decrease was found in the right TA for GI-1 compared to GI-2 in both sitting (p = 0.008) and standing (p = 0.01) positions. In the left TA, the activity decreased in the sitting posture during non-GI (p = 0.004) and GI-1 (p = 0.009) in comparison to GI-2. No differences were found for GM. The subjective level of imagination difficulty improved for GI-2 in comparison to GI-1 in both postures (p < 0.001). Previous sensorimotor experience with real gait execution and sitting posture potentiate TA activity decrease during GI. These findings contribute to the understanding of neural mechanisms beyond GI.

Stability of mental motor-imagery classification in EEG depends on the choice of classifier model and experiment design, but not on signal preprocessing

Introduction

Modern consciousness research has developed diagnostic tests to improve the diagnostic accuracy of different states of consciousness via electroencephalography (EEG)-based mental motor imagery (MI), which is still challenging and lacks a consensus on how to best analyse MI EEG-data. An optimally designed and analyzed paradigm must detect command-following in all healthy individuals, before it can be applied in patients, e.g., for the diagnosis of disorders of consciousness (DOC).

Methods

We investigated the effects of two important steps in the raw signal preprocessing on predicting participant performance (F1) and machine-learning classifier performance (area-under-curve, AUC) in eight healthy individuals, that are based solely on MI using high-density EEG (HD-EEG): artifact correction (manual correction with vs. without Independent Component Analysis [ICA]), region of interest (ROI; motor area vs. whole brain), and machine-learning algorithm (support-vector machine [SVM] vs. k-nearest neighbor [KNN]).

Results

Results revealed no significant effects of artifact correction and ROI on predicting participant performance (F1) and classifier performance (AUC) scores (all ps > 0.05) in the SVM classification model. In the KNN model, ROI had a significant influence on the classifier performance [F(1,8.939) = 7.585, p = 0.023]. There was no evidence for artifact correction and ROI selection changing the prediction of participants performance and classifier performance in EEG-based mental MI if using SVM-based classification (71-100% correct classifications across different signal preprocessing methods). The variance in the prediction of participant performance was significantly higher when the experiment started with a resting-state compared to a mental MI task block [X2(1) = 5.849, p = 0.016].

Discussion

Overall, we could show that classification is stable across different modes of EEG signal preprocessing when using SVM models. Exploratory analysis gave a hint toward potential effects of the sequence of task execution on the prediction of participant performance, which should be taken into account in future studies.

Timing-specific patterns of cerebral activations during motor imagery: A case study of the expert brain signature

Brain activations elicited during motor imagery (MI) in experts are typically reduced compared to novices, which is interpreted as a neurophysiological correlate of increased neural efficiency. However, the modulatory effects of MI speed on expertise-related differences in brain activation remains largely unknown. In the present pilot study, we compared the magnetoencephalographic (MEG) correlates of MI in an Olympic medallist and an amateur athlete under conditions of slow, real-time and fast MI. Data revealed event-related changes in the time course of alpha (8-12 Hz) power of MEG oscillations, for all timing conditions. We found that slow MI was associated with a corollary increase in neural synchronization, in both participants. Sensor-level and source-level analyses however disclosed differences between the two expertise levels. The Olympic medallist achieved greater activation of cortical sensorimotor networks than the amateur athlete, particularly during fast MI. Fast MI elicited the strongest event-related desynchronization of alpha oscillations, which was generated from cortical sensorimotor sources in the Olympic medallist, but not in the amateur athlete. Taken together, data suggest that fast MI is a particularly demanding form of motor cognition, putting a specific emphasis on cortical sensorimotor networks to achieve the formation of accurate motor representations under demanding timing constraints.

Imagined Timed Up and Go test (iTUG) in people with Parkinson's Disease: test-retest reliability and validity

PURPOSE

To determine the test-retest reliability and validity of the Imagined Timed Up and Go Test (iTUG) as a Motor Imagery measure of temporal accuracy in people with Parkinson's Disease (PD).

MATERIALS AND METHODS

A descriptive study was conducted following the GRRAS recommendations. Thirty-two people with idiopathic, mild to moderate PD (Hoehn and Yahr I-III), without cognitive impairment (MMSE ≥ 24), were assessed twice (7-15 days apart) with the iTUG. The absolute unadjusted difference in seconds, and the absolute adjusted difference as percentage of estimation error, between real and imagined TUG times, were calculated as outcome measures. Test-retest reliability was assessed using a two-way mixed-effects model of the ICC. Construct validity was tested with the Imagined Box and Blocks Test (iBBT) and convergent validity with clinical characteristics of PD, using the Spearman's rank correlation coefficient.

RESULTS

The ICC for the unadjusted and adjusted measures of the iTUG was ICC = 0.61 and ICC = 0.55, respectively. Correlations between iTUG and iBBT were not statistically significant. The iTUG was partially correlated to clinical characteristics of PD.

CONCLUSIONS

Test-retest reliability of the iTUG was moderate. Construct validity between iTUG and iBBT was poor, so caution should be taken when using them concurrently to assess imagery's temporal accuracy.

Psychological skills training impacts autonomic nervous system responses to stress during sport-specific imagery: An exploratory study in junior elite shooters

This study investigated the effects of psychological skills training (PST) in shooters psychophysiologically using heart rate variability (HRV) in addition to psychological questionnaires and participant interviews. Five junior pistol shooters participated in an 8-week PST program consisting of a group session per week followed by individual counseling. Before and after PST, we collected electrocardiography data during rest, mental imagery of sport-related crisis situations, and successful performance, to analyze differences in HRV indices. Participants also responded to the Psychological Skills Inventory for Archery and Shooting (PSIAS), Intrinsic Motivation Inventory (IMI), Sports Anxiety Scale (SAS), and Trait Sport Confidence Inventory (TSCI). Results showed that the perceived competence (pre: 2.52 ± 0.95, post: 3.36 ± 0.73, p = 0.049) and trait sport confidence (pre: 4.94 ± 1.17, post: 6.60 ± 0.65, p = 0.049) significantly improved after PST. The analysis of HRV indicated that the ratio of low-frequency power to high-frequency power (LF/HF ratio) decreased significantly during imagery of crisis (pre: 3.4 ± 2.3, post: 1.014 ± 0.71, p = 0.038) and success (pre: 1.933 ± 0.917, post: 0.988 ± 0.572, p = 0.046), reflecting a strengthened autonomic nervous system's responsiveness to stress. Our findings illustrate that PST can help athletes better cope with psychologically disturbed situations during competition, by providing psychophysiological evidence through HRV changes.

Motor imagery electroencephalogram classification algorithm based on joint features in the spatial and frequency domains and instance transfer

Introduction

Motor imagery electroencephalography (MI-EEG) has significant application value in the field of rehabilitation, and is a research hotspot in the brain-computer interface (BCI) field. Due to the small training sample size of MI-EEG of a single subject and the large individual differences among different subjects, existing classification models have low accuracy and poor generalization ability in MI classification tasks.

Methods

To solve this problem, this paper proposes a electroencephalography (EEG) joint feature classification algorithm based on instance transfer and ensemble learning. Firstly, the source domain and target domain data are preprocessed, and then common space mode (CSP) and power spectral density (PSD) are used to extract spatial and frequency domain features respectively, which are combined into EEG joint features. Finally, an ensemble learning algorithm based on kernel mean matching (KMM) and transfer learning adaptive boosting (TrAdaBoost) is used to classify MI-EEG.

Results

To validate the effectiveness of the algorithm, this paper compared and analyzed different algorithms on the BCI Competition IV Dataset 2a, and further verified the stability and effectiveness of the algorithm on the BCI Competition IV Dataset 2b. The experimental results show that the algorithm has an average accuracy of 91.5% and 83.7% on Dataset 2a and Dataset 2b, respectively, which is significantly better than other algorithms.

Discussion

The statement explains that the algorithm fully exploits EEG signals and enriches EEG features, improves the recognition of the MI signals, and provides a new approach to solving the above problem.

Hand and Foot Selection in Mental Body Rotations Involves Motor-Cognitive Interactions

Action imagery involves the mental representation of an action without overt execution, and can contribute to perspective taking, such as that required for left-right judgments in mental body rotation tasks. It has been shown that perspective (back view, front view), rotational angle (head-up, head-down), and abstractness (abstract, realistic) of the stimulus material influences speed and correctness of the judgement. The present studies investigated whether left-right judgements are more difficult on legs than on arms and whether the type of limb interacts with the other factors. Furthermore, a combined score for speed and accuracy was explored to eliminate possible tradeoffs and to obtain the best possible measure of subjects' individual ability. Study 1 revealed that the front view is more difficult than the back view because it involves a vertical rotation in perspective taking. Head-down rotations are more difficult than head-up rotations because they involve a horizontal rotation in perspective taking. Furthermore, leg stimuli are more difficult than hand stimuli, particularly in head-down rotations. In Study 2, these findings were replicated in abstract stimuli as well as in realistic stimuli. In addition, perspective taking for realistic stimuli in the back view is easier than realistic stimuli in the front view or abstract stimuli (in both perspectives). We conclude that realistic stimulus material facilitates task comprehension and amplifies the effects of perspective. By replicating previous findings, the linear speed-accuracy score was shown to be a valid measure to capture performance in mental body rotations.

Improved classification performance of EEG-fNIRS multimodal brain-computer interface based on multi-domain features and multi-level progressive learning

Electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) have potentially complementary characteristics that reflect the electrical and hemodynamic characteristics of neural responses, so EEG-fNIRS-based hybrid brain-computer interface (BCI) is the research hotspots in recent years. However, current studies lack a comprehensive systematic approach to properly fuse EEG and fNIRS data and exploit their complementary potential, which is critical for improving BCI performance. To address this issue, this study proposes a novel multimodal fusion framework based on multi-level progressive learning with multi-domain features. The framework consists of a multi-domain feature extraction process for EEG and fNIRS, a feature selection process based on atomic search optimization, and a multi-domain feature fusion process based on multi-level progressive machine learning. The proposed method was validated on EEG-fNIRS-based motor imagery (MI) and mental arithmetic (MA) tasks involving 29 subjects, and the experimental results show that multi-domain features provide better classification performance than single-domain features, and multi-modality provides better classification performance than single-modality. Furthermore, the experimental results and comparison with other methods demonstrated the effectiveness and superiority of the proposed method in EEG and fNIRS information fusion, it can achieve an average classification accuracy of 96.74% in the MI task and 98.42% in the MA task. Our proposed method may provide a general framework for future fusion processing of multimodal brain signals based on EEG-fNIRS.

Prolonged disorders of consciousness: A response to a "critical evaluation of the new UK guidelines."

BACKGROUND

In 2020, The London Royal College of Physicians published "Prolonged disorders of consciousness following sudden-onset brain injury: national clinical guidelines". In 2021, in the journal Brain, Scolding et al. published "a critical evaluation of the new UK guidelines". This evaluation focussed on one of the 73 recommendations in the National Clinical Guidelines. They also alleged that the guidelines were unethical.

CRITICISMS

They criticised our recommendation not to use activation protocols using fMRI, electroencephalography, or Positron Emission Tomography. They claim these tests can (a) detect 'covert consciousness', (b) add predictive value and (c) should be part of routine clinical care. They also suggest that our guideline was driven by cost considerations, leading to clinicians deciding to withdraw treatment at 72 h.

EVIDENCE

Our detailed review of the evidence confirms the American Academy of Neurology Practise Guideline (2018) and the European Academy of Neurology Guideline (2020), which agree that insufficient evidence supports their approach.

ETHICS

The ethical objections are based on unwarranted assumptions. Our guideline does not make any recommendations about management until at least four weeks have passed. We explicitly recommend that expert assessors undertake ongoing surveillance and monitoring; we do not suggest that patients be abandoned. Our recommendation will increase the cost We had ethicists in the working party.

CONCLUSION

We conclude the "critical evaluation" fails to provide evidence for their criticism and that the ethical objections arise from incorrect assumptions and unsupported interpretations of evidence and our guideline. The 2020 UK national guidelines remain valid.

Stabilometric Correlates of Motor and Motor Imagery Expertise

Motor Imagery (MI) reproduces cognitive operations associated with the actual motor preparation and execution. Postural recordings during MI reflect somatic motor commands targeting peripheral effectors involved in balance control. However, how these relate to the actual motor expertise and may vary along with the MI modality remains debated. In the present experiment, two groups of expert and non-expert gymnasts underwent stabilometric assessments while performing physically and mentally a balance skill. We implemented psychometric measures of MI ability, while stabilometric variables were calculated from the center of pressure (COP) oscillations. Psychometric evaluations revealed greater MI ability in experts, specifically for the visual modality. Experts exhibited reduced surface COP oscillations in the antero-posterior axis compared to non-experts during the balance skill (14.90%, 95% CI 34.48–4.68, p &lt; 0.05). Experts further exhibited reduced length of COP displacement in the antero-posterior axis and as a function of the displacement area during visual and kinesthetic MI compared to the control condition (20.51%, 95% CI 0.99–40.03 and 21.85%, 95% CI 2.33–41.37, respectively, both p &lt; 0.05). Predictive relationships were found between the stabilometric correlates of visual MI and physical practice of the balance skill, as well as between the stabilometric correlates of kinesthetic MI and the training experience in experts. Present results provide original stabilometric insights into the relationships between MI and expertise level. While data support the incomplete inhibition of postural commands during MI, whether postural responses during MI of various modalities mirror the level of motor expertise remains unclear.

A Long Short-Term Memory Network for Sparse Spatiotemporal EEG Source Imaging

EEG inverse problem is underdetermined, which poses a long standing challenge in Neuroimaging. The combination of source-imaging and analysis of cortical directional networks enables us to noninvasively explore the underlying neural processes. However, existing EEG source imaging approaches mainly focus on performing the direct inverse operation for source estimation, which will be inevitably influenced by noise and the strategy used to find the inverse solution. Here, we develop a new source imaging technique, Deep Brain Neural Network (DeepBraiNNet), for robust sparse spatiotemporal EEG source estimation. In DeepBraiNNet, considering that Recurrent Neural Network (RNN) are usually "deep" in temporal dimension and thus suitable for time sequence modelling, the RNN with Long Short-Term Memory (LSTM) is utilized to approximate the inverse operation for the lead field matrix instead of performing the direct inverse operation, which avoids the possible effect of the direct inverse operation on the underdetermined lead field matrix prone to be influenced by noise. Simulations on various source patterns and noise conditions confirmed that the proposed approach could actually recover the spatiotemporal sources well, outperforming existing state of-the-art methods. DeepBraiNNet also estimated sparse MI related activation patterns when it was applied to a real Motor Imagery dataset, consistent with other findings based on EEG and fMRI. Based on the spatiotemporal sources estimated from DeepBraiNNet, we constructed MI related cortical neural networks, which clearly exhibited strong contralateral network patterns for the two MI tasks. Consequently, DeepBraiNNet may provide an alternative way different from the conventional approaches for spatiotemporal EEG source imaging.

The Impact of Motor Imageries on Aesthetic Judgment of Chinese Calligraphy: An fMRI Study

Previous behavioral studies on aesthetics demonstrated that there was a close association between perceived action and aesthetic appreciation. However, few studies explored whether motor imagery would influence aesthetic experience and its neural substrates. In the current study, Chinese calligraphy was used as the stimuli to explore the relationship between the motor imagery and the aesthetic judgments of a participant using functional magnetic resonance imaging. The imaging results showed that, compared with the baseline, the activation of the brain regions [e.g., anterior cingulate cortex (ACC), putamen, and insula] involved in perceptual processing, cognitive judgments, aesthetic emotional, and reward processing was observed after the participants performed motor imagery tasks. The contrast analyses within aesthetic judgments showed that the kinesthetic imagery significantly activated the middle frontal gyrus, postcentral gyrus, ACC, and thalamus. Generally, these areas were considered to be closely related to positive aesthetic experience and suggested that motor imagery, especially kinesthetic imagery, might be specifically associated with the aesthetic appreciation of Chinese calligraphy.

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.

Motor imagery for pain and motor function after spinal cord injury: a systematic review

STUDY DESIGN

Systematic review.

OBJECTIVES

To evaluate the therapeutic benefits of motor imagery (MI) for the people with spinal cord injury (SCI).

SETTING

International.

METHODS

We searched electronic bibliographic databases, trial registers, and relevant reference lists. The review included experimental and quasi-experimental study designs as well as observational studies. For the critical appraisal of the 18 studies retrieved (three RCT, seven quasi-RCT, eight observational), we used instruments from the Joanna Briggs Institute. The primary outcome measure was pain. Secondary outcome measures included motor function and neurophysiological parameters. Adverse effects were extracted if reported in the included studies. Because of data heterogeneity, only a qualitative synthesis is offered.

RESULTS

The included studies involved 282 patients. In most, results were an improvement in motor function and decreased pain; however, some reported no effect or an increase in pain. Although protocols of MI intervention were heterogeneous, sessions of 8-20 min were used for pain treatments, and of 30-60 min were used for motor function improvement. Neurophysiological measurements showed changes in brain region activation and excitability imposed by SCI, which were partially recovered by MI interventions. No serious adverse effects were reported.

CONCLUSIONS

High heterogeneity in the SCI population, MI interventions, and outcomes measured makes it difficult to judge the therapeutic effects and best MI intervention protocol, especially for people with SCI with neuropathic pain. Further clinical trials evaluating MI intervention as adjunct therapy for pain in SCI patients are warranted.

Behind the Scenes of Noninvasive Brain-Computer Interfaces: A Review of Electroencephalography Signals, How They Are Recorded, and Why They Matter

Purpose

Brain-computer interface (BCI) techniques may provide computer access for individuals with severe physical impairments. However, the relatively hidden nature of BCI control obscures how BCI systems work behind the scenes, making it difficult to understand how electroencephalography (EEG) records the BCI related brain signals, what brain signals are recorded by EEG, and why these signals are targeted for BCI control. Furthermore, in the field of speech-language-hearing, signals targeted for BCI application have been of primary interest to clinicians and researchers in the area of augmentative and alternative communication (AAC). However, signals utilized for BCI control reflect sensory, cognitive and motor processes, which are of interest to a range of related disciplines including speech science.

Method

This tutorial was developed by a multidisciplinary team emphasizing primary and secondary BCI-AAC related signals of interest to speech-language-hearing.

Results

An overview of BCI-AAC related signals are provided discussing 1) how BCI signals are recorded via EEG, 2) what signals are targeted for non-invasive BCI control, including the P300, sensorimotor rhythms, steady state evoked potentials, contingent negative variation, and the N400, and 3) why these signals are targeted. During tutorial creation, attention was given to help support EEG and BCI understanding for those without an engineering background.

Conclusion

Tutorials highlighting how BCI-AAC signals are elicited and recorded can help increase interest and familiarity with EEG and BCI techniques and provide a framework for understanding key principles behind BCI-AAC design and implementation.

Neurophysiological Analysis of Intermanual Transfer in Motor Learning

The purpose of this study was to examine the effect of motor training on motor imagery (MI), by comparing motor performance and motor cortex excitability changes with and without intermanual transfer of motor learning. Intermanual transfer was investigated in terms of excitability changes in the motor cortex and motor performance from right hand training to left hand performance. Participants were assigned to a transfer training group and a control group. We recorded motor evoked potentials (MEPs) induced by transcranial magnetic stimulation (TMS), applied to the left extensor carpi radialis (ECR) both with and without intermanual transfer. The results showed that after learning by the right hand, MEPs decreased during left hand MI. MEPs during MI were significantly decreased by unilateral training in the transfer training group. Since intermanual transfer plays an important role in stabilizing performance by the contralateral side, this result suggests that unilateral training decreases MEPs during MI on the contralateral side. In the control group, without right hand training, MEPs significantly increased after left hand training during MI. In the trained side, we found increased excitability in the agonist muscle area of the primary motor cortex. However, in the untrained side, excitability decreased in the homonymous muscle area of the primary motor cortex. This constitutes an increase in inhibitory effects and suggests that excitability changes in the respective neural circuit contribute to skilled performance by the ipsilateral and contralateral sides in the same motor task.

Emotional Theory of Rationality

In recent decades, the existence of a close relationship between emotional phenomena and rational processes has certainly been established, yet there is still no unified definition or effective model to describe them. To advance our understanding of the mechanisms governing the behavior of living beings, we must integrate multiple theories, experiments, and models from both fields. In this article we propose a new theoretical framework that allows integrating and understanding the emotion-cognition duality, from a functional point of view. Based on evolutionary principles, our reasoning adds to the definition and understanding of emotion, justifying its origin, explaining its mission and dynamics, and linking it to higher cognitive processes, mainly with attention, cognition, decision-making, and consciousness. According to our theory, emotions are the mechanism for brain function optimization, aside from the contingency and stimuli prioritization system. As a result of this approach, we have developed a dynamic systems-level model capable of providing plausible explanations for certain psychological and behavioral phenomena and establishing a new framework for the scientific definition of some fundamental psychological terms.

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.

Descriptive pilot study of vividness and temporal equivalence during motor imagery training after quadriplegia

BACKGROUND

Motor imagery (MI) training is often used to improve physical practice (PP), and the functional equivalence between imagined and practiced movements is widely considered essential for positive training outcomes.

OBJECTIVE

We previously showed that a 5-week MI training program improved tenodesis grasp in individuals with C6-C7 quadriplegia. Here we investigated whether functional equivalence changed during the course of this training program.

METHODS

In this descriptive pilot study, we retrospectively analyzed data for 6 individuals with C6-C7 quadriplegia (spinal cord injured [SCI]) and 6 healthy age-matched controls who trained for 5 weeks in visual and kinesthetic motor imagery or visualization of geometric shapes (controls). Before training, we assessed MI ability by using the Kinesthetic and Visual Imagery Questionnaire (KVIQ). We analyzed functional equivalence by vividness measured on a visual analog scale (0-100) and MI/PP time ratios computed from imagined and physically practiced movement durations measured during MI training. These analyses were re-run considering that half of the participants with quadriplegia were good imagers and the other half were poor imagers based on KVIQ scores. To investigate generalization of training effects, we analyzed MI/PP ratios for an untrained pointing task before (3 baseline measures), immediately after, and 2 months after training.

RESULTS

During MI training, imagery vividness increased significantly. Only the good imagers evolved toward temporal equivalence during training. Good imagers were also the only participants who showed changes in temporal equivalence on the untrained pointing task.

CONCLUSION

This is the first study reporting improvement in functional equivalence during an MI training program that improved tenodesis grasp in individuals with C6-C7 quadriplegia. We recommend that clinical MI programs focus primarily on vividness and suggest that feedback about movement duration could potentially improve temporal equivalence, which could in turn lead to further improvement in PP.

Suppressing Systemic Interference in fNIRS Monitoring of the Hemodynamic Cortical Response to Motor Execution and Imagery

Hemodynamic response to motor execution (ME) and motor imagery (MI) was investigated using functional near-infrared spectroscopy (fNIRS). We used a 31 channel fNIRS system which allows non-invasive monitoring of cerebral oxygenation changes induced by cortical activation. Sixteen healthy subjects (mean-age 24.5 yeas) were recruited and the changes in concentration of hemoglobin were examined during right and left hand finger tapping tasks and kinesthetic MI. To suppress the systemic physiological interference, we developed a preprocessing procedure which prevents over-activated reporting in NIRS-SPM. In the condition of ME, more activation was observed in the anterior part of the motor cortex including the pre-motor and supplementary motor area (pre-motor and SMA), primary motor cortex (M1) and somatosensory motor cortex (SMC; t₍₁₅₎ > 2.27), however, in the condition of MI, more activation was found in the posterior part of motor cortex including SMC (t₍₁₅₎ > 1.81), which is in line with previous observations with functional magnetic resonance imaging (fMRI).

Suppressing Systemic Interference in fNIRS Monitoring of the Hemodynamic Cortical Response to Motor Execution and Imagery

Hemodynamic response to motor execution (ME) and motor imagery (MI) was investigated using functional near-infrared spectroscopy (fNIRS). We used a 31 channel fNIRS system which allows non-invasive monitoring of cerebral oxygenation changes induced by cortical activation. Sixteen healthy subjects (mean-age 24.5 yeas) were recruited and the changes in concentration of hemoglobin were examined during right and left hand finger tapping tasks and kinesthetic MI. To suppress the systemic physiological interference, we developed a preprocessing procedure which prevents over-activated reporting in NIRS-SPM. In the condition of ME, more activation was observed in the anterior part of the motor cortex including the pre-motor and supplementary motor area (pre-motor and SMA), primary motor cortex (M1) and somatosensory motor cortex (SMC; t₍₁₅₎ > 2.27), however, in the condition of MI, more activation was found in the posterior part of motor cortex including SMC (t₍₁₅₎ > 1.81), which is in line with previous observations with functional magnetic resonance imaging (fMRI).

Experience-dependent modulation of alpha and beta during action observation and motor imagery

Background

EEG studies investigating the neural networks that facilitate action observation (AO) and kinaesthetic motor imagery (KMI) have shown reduced, or desynchronized, power in the alpha (8–12 Hz) and beta (13–30 Hz) frequency bands relative to rest, reflecting efficient activation of task-relevant areas. Functional modulation of these networks through expertise in dance has been established using fMRI, with greater activation among experts during AO. While there is evidence for experience-dependent plasticity of alpha power during AO of dance, the influence of familiarity on beta power during AO, and alpha and beta activity during KMI, remain unclear. The purpose of the present study was to measure the impact of familiarity on confidence ratings and EEG activity during (1) AO of a brief ballet sequence, (2) KMI of this same sequence, and (3) KMI of non-dance movements among ballet dancers, dancers from other genres, and non-dancers.

Results

Ballet dancers highly familiar with the genre of the experimental stimulus demonstrated higher individual alpha peak frequency (iAPF), greater alpha desynchronization, and greater task-related beta power during AO, as well as faster iAPF during KMI of non-dance movements. While no between-group differences in alpha or beta power were observed during KMI of dance or non-dance movements, all participants showed significant desynchronization relative to baseline, and further desynchronization during dance KMI relative to non-dance KMI indicative of greater cognitive load.

Conclusions

These findings confirm and extend evidence for experience-dependent plasticity of alpha and beta activity during AO of dance and KMI. We also provide novel evidence for modulation of iAPF that is faster when tuned to the specific motor repertoire of the observer. By considering the multiple functional roles of these frequency bands during the same task (AO), we have disentangled the compounded contribution of familiarity and expertise to alpha desynchronization for mediating task engagement among familiar ballet dancers and reflecting task difficulty among unfamiliar non-dance subjects, respectively. That KMI of a complex dance sequence relative to everyday, non-dance movements recruits greater cognitive resources suggests it may be a more powerful tool in driving neural plasticity of action networks, especially among the elderly and those with movement disorders.

Cortical Dynamic Causality Network for Auditory-Motor Tasks

Motor preparation and execution require the interactions of a large-scale brain network, while the study of the dynamic changes of their interactions could uncover the underlying neural mechanism of the corresponding information processing. This dynamic analysis requires high temporal resolution of the recorded signals. Electroencephalogram (EEG) with high temporal resolution has been widely used in related studies. However, studies based on scalp EEG always lead to distorted results, due to scalp volume conduction, compared with that of cortically recorded signals. In the current study, the dynamic networks of motor preparation and execution are investigated using Go/No-go tasks performed with the left/right hand. In the analysis, the EEG source localization and dynamic causal model are combined together to investigate the neural processes of motor preparation and execution. The results show that similar network patterns with nodes distributed in the bilateral occipital lobe, bilateral temporal lobe, bilateral dorsolateral prefrontal cortex, and contralateral supplementary motor area could be revealed for both the Go and No-go tasks. Statistical testing further indicates that stronger couplings with the supplementary motor area could be found in Go and right-hand response tasks compared with No-go and left-hand response tasks, respectively. The findings in the current study demonstrate that the information exchange within the motor related brain networks plays an important role for motor related functions, i.e., the different motor functions may have the different information exchange and processing network patterns.

Can motor imagery and hypnotic susceptibility explain Conversion Disorder with motor symptoms?

Marked distortions in sense of agency can be induced by hypnosis in susceptible individuals, including alterations in subjective awareness of movement initiation and control. These distortions, with associated disability, are similar to those experienced with Conversion Disorder (CD), an observation that has led to the hypothesis that hypnosis and CD share causal mechanisms. The purpose of this review is to explore the relationships among motor imagery (MI), hypnotic susceptibility, and CD, then to propose how MI ability may contribute to hypnotic responding and CD. Studies employing subjective assessments of mental imagery have found little association between imagery abilities and hypnotic susceptibility. A positive association between imagery abilities and hypnotic susceptibility becomes apparent when objective measures of imagery ability are employed. A candidate mechanism to explain motor responses during hypnosis is kinaesthetic MI, which engages a strategy that involves proprioception or the "feel" of movement when no movement occurs. Motor suppression imagery (MSI), a strategy involving inhibition of movement, may provide an alternate objective measurable phenomenon that underlies both hypnotic susceptibility and CD. Evidence to date supports the idea that there may be a positive association between kinaesthetic MI ability and hypnotic susceptibility. Additional evidence supports a positive association between hypnotic susceptibility and CD. Disturbances in kinaesthetic MI performance in CD patients indicate that MI mechanisms may also underlie CD symptoms. Further investigation of the above relationships is warranted to explain these phenomena, and establish theoretical explanations underlying sense of agency.

Embodied mental rotation: a special link between egocentric transformation and the bodily self

This experiment investigated the influence of motor expertise on object-based versus egocentric transformations in a chronometric mental rotation task using images of either the own or another person’s body as stimulus material. According to the embodied cognition viewpoint, we hypothesized motor-experts to outperform non-motor experts specifically in the egocentric condition because of higher kinesthetic representation and motor simulations compared to object-based transformations. In line with this, we expected that images of the own body are solved faster than another person’s body stimuli. Results showed a benefit of motor expertise and representations of another person’s body, but only for the object-based transformation task. That is, this other-advantage diminishes in egocentric transformations. Since motor experts did not show any specific expertise in rotational movements, we concluded that using human bodies as stimulus material elicits embodied spatial transformations, which facilitates performance exclusively for egocentric transformations. Regarding stimulus material, the other-advantage ascribed to increased self-awareness-consciousness distracting attention-demanding resources, disappeared in the egocentric condition. This result may be due to the stronger link between the bodily self and motor representations compared to that emerging in object-based transformations.

Experts bodies, experts minds: How physical and mental training shape the brain

Skill learning is the improvement in perceptual, cognitive, or motor performance following practice. Expert performance levels can be achieved with well-organized knowledge, using sophisticated and specific mental representations and cognitive processing, applying automatic sequences quickly and efficiently, being able to deal with large amounts of information, and many other challenging task demands and situations that otherwise paralyze the performance of novices. The neural reorganizations that occur with expertise reflect the optimization of the neurocognitive resources to deal with the complex computational load needed to achieve peak performance. As such, capitalizing on neuronal plasticity, brain modifications take place over time-practice and during the consolidation process. One major challenge is to investigate the neural substrates and cognitive mechanisms engaged in expertise, and to define “expertise” from its neural and cognitive underpinnings. Recent insights showed that many brain structures are recruited during task performance, but only activity in regions related to domain-specific knowledge distinguishes experts from novices. The present review focuses on three expertise domains placed across a motor to mental gradient of skill learning: sequential motor skill, mental simulation of the movement (motor imagery), and meditation as a paradigmatic example of “pure” mental training. We first describe results on each specific domain from the initial skill acquisition to expert performance, including recent results on the corresponding underlying neural mechanisms. We then discuss differences and similarities between these domains with the aim to identify the highlights of the neurocognitive processes underpinning expertise, and conclude with suggestions for future research.

Performance improvements from imagery: evidence that internal visual imagery is superior to external visual imagery for slalom performance

We report three experiments investigating the hypothesis that use of internal visual imagery (IVI) would be superior to external visual imagery (EVI) for the performance of different slalom-based motor tasks. In Experiment 1, three groups of participants (IVI, EVI, and a control group) performed a driving-simulation slalom task. The IVI group achieved significantly quicker lap times than EVI and the control group. In Experiment 2, participants performed a downhill running slalom task under both IVI and EVI conditions. Performance was again quickest in the IVI compared to EVI condition, with no differences in accuracy. Experiment 3 used the same group design as Experiment 1, but with participants performing a downhill ski-slalom task. Results revealed the IVI group to be significantly more accurate than the control group, with no significant differences in time taken to complete the task. These results support the beneficial effects of IVI for slalom-based tasks, and significantly advances our knowledge related to the differential effects of visual imagery perspectives on motor performance.

How skill expertise shapes the brain functional architecture: an fMRI study of visuo-spatial and motor processing in professional racing-car and naïve drivers

The present study was designed to investigate the brain functional architecture that subserves visuo-spatial and motor processing in highly skilled individuals. By using functional magnetic resonance imaging (fMRI), we measured brain activity while eleven Formula racing-car drivers and eleven ‘naïve’ volunteers performed a motor reaction and a visuo-spatial task. Tasks were set at a relatively low level of difficulty such to ensure a similar performance in the two groups and thus avoid any potential confounding effects on brain activity due to discrepancies in task execution. The brain functional organization was analyzed in terms of regional brain response, inter-regional interactions and blood oxygen level dependent (BOLD) signal variability. While performance levels were equal in the two groups, as compared to naïve drivers, professional drivers showed a smaller volume recruitment of task-related regions, stronger connections among task-related areas, and an increased information integration as reflected by a higher signal temporal variability. In conclusion, our results demonstrate that, as compared to naïve subjects, the brain functional architecture sustaining visuo-motor processing in professional racing-car drivers, trained to perform at the highest levels under extremely demanding conditions, undergoes both ‘quantitative’ and ‘qualitative’ modifications that are evident even when the brain is engaged in relatively simple, non-demanding tasks. These results provide novel evidence in favor of an increased ‘neural efficiency’ in the brain of highly skilled individuals.

Individual differences in neural regions functionally related to real and imagined stuttering

Recent brain imaging investigations of developmental stuttering show considerable disagreement regarding which regions are related to stuttering. These divergent findings have been mainly derived from group studies. To investigate functional neurophysiology with improved precision, an individual-participant approach (N=4) using event-related functional magnetic resonance imaging and test-retest reliability measures was performed while participants produced fluent and stuttered single words during two separate occasions. A parallel investigation required participants to imagine stuttering or not stuttering on single words. The overt and covert production tasks produced considerable within-subject agreement of activated voxels across occasions, but little within-subject agreement between overt and covert task activations. However, across-subject agreement for regions activated by the overt and covert tasks was minimal. These results suggest that reliable effects of stuttering are participant-specific, an implication that might correspond to individual differences in stuttering severity and functional compensation due to related structural abnormalities.

Motor imagery in stroke patients, or plegic patients with spinal cord or peripheral diseases

OBJECTIVES

When motor imagery (MI) is impaired in stroke patients, it is not clear, whether this is caused by the central lesion with a disruption of networks or this may be due to inactivity/lack of practice following hemiparesis. To answer this question, we investigated MI in two groups of patients: stroke patients and patients with no central lesion, who suffered high-grade tetraparesis caused by myopathy or spinal muscular atrophy.

MATERIALS AND METHODS

The first study measured MI in 31 sub-acute and chronic stroke patients with hand paresis. We used self-assessment questionnaires [Kinaesthetic and Visual Imagery Questionnaire (KVIQ), the Vividness of Motor Imagery Questionnaire (VMIQ)] as well as a new chronometric test (mental version and normal/physical version of Box and Block Test). The second study assessed MI in 10 patients without a central lesion, but with severe tetraparesis of peripheral origin. They were incapable of performing the requested task physically.

RESULTS

MI in patients was better (i) for the third-person (VMIQ(3.P) ) compared to the first-person perspective (VMIQ(1.P) ), (ii) in patients without sensory impairment compared to those with impaired proprioception, (iii) in patients with light paresis compared to severe paresis and (iv) for the non-affected than the affected hand (KVIQ-10). Patients with severe tetraparesis were able to imagine another person's knee bends, but were not capable of imagining themselves performing knee bends.

CONCLUSIONS

MI may be hampered on the affected side in severely paretic patients, particularly in the presence of impaired proprioception. Remarkably, the second study illustrates that motor experiences shape MI. This confirms the close relationship between MI and movement execution. The study advocates the careful use of test batteries for assessment of MI when investigating mental training in clinical trials. Not all patients might benefit to the same extent from MI training. This is possibly contingent on intact proprioception and preserved MI.

Befunde aus EEG-Untersuchungen zum Mentalen Training

Mentales Training (MT) im Sinne der planmäßig wiederholten Vorstellung eines Bewegungsablaufes ist ein zentraler Gegenstand sportpsychologischer Forschung. Im Hochleistungssport und in der Rehabilitation wird es zur Optimierung von Bewegungen eingesetzt. Einen Erklärungsansatz der Trainingswirkung bietet die Simulationstheorie mit dem zentralen Postulat, dass Bewegungsausführung und -vorstellung gleiche neuronale Strukturen aktivieren (funktionale Äquivalenz). Diese Annahme wurde mittels verschiedener neurophysiologischer Methoden geprüft, die teils zu widersprüchlichen Befunden führten. Die Elektroenzephalographie (EEG) kann unserer Ansicht nach dabei helfen, Lücken im theoretischen Erkenntnisprozess zu schließen. In diesem Artikel geben wir einen Überblick über die aktuelle Befundlage zum Mentalen Training mittels EEG. Es sollen drei wesentliche Vorteile der Methode aufgezeigt werden: (a) das EEG liefert Maße der neurophysiologischen Aktivität mit hoher zeitlicher Auflösung, (b) technische Weiterentwicklungen (drahtlose Hardware, tragbare Ausrüstung) erlauben die notwendige Bewegungsfreiheit für eine Anwendung im Sportkontext und (c) in der Rehabilitation kann die Vorstellung von Bewegungen als mentale Strategie dienen, um eine Neuroprothese auf Basis von Hirnsignalen zu steuern.

A combined robotic and cognitive training for locomotor rehabilitation: evidences of cerebral functional reorganization in two chronic traumatic brain injured patients

It has been demonstrated that automated locomotor training can improve walking capabilities in spinal cord-injured subjects but its effectiveness on brain damaged patients has not been well established. A possible explanation of the discordant results on the efficacy of robotic training in patients with cerebral lesions could be that these patients, besides stimulation of physiological motor patterns through passive leg movements, also need to train the cognitive aspects of motor control. Indeed, another way to stimulate cerebral motor areas in paretic patients is to use the cognitive function of motor imagery. A promising possibility is thus to combine sensorimotor training with the use of motor imagery. The aim of this paper is to assess changes in brain activations after a combined sensorimotor and cognitive training for gait rehabilitation. The protocol consisted of the integrated use of a robotic gait orthosis prototype with locomotor imagery tasks. Assessment was conducted on two patients with chronic traumatic brain injury and major gait impairments, using functional magnetic resonance imaging. Physiatric functional scales were used to assess clinical outcomes. Results showed greater activation post-training in the sensorimotor and supplementary motor cortices, as well as enhanced functional connectivity within the motor network. Improvements in balance and, to a lesser extent, in gait outcomes were also found.

The delayed and noisy nervous system: implications for neural control

Recent advances in the study of delay differential equations draw attention to the potential benefits of the interplay between random perturbations ('noise') and delay in neural control. The phenomena include transient stabilizations of unstable steady states by noise, control of fast movements using time-delayed feedback and the occurrence of long-lived delay-induced transients. In particular, this research suggests that the interplay between noise and delay necessitates the use of intermittent, discontinuous control strategies in which corrective movements are made only when controlled variables cross certain thresholds. A potential benefit of such strategies is that they may be optimal for minimizing energy expenditures associated with control. In this paper, the concepts are made accessible by introducing them through simple illustrative examples that can be readily reproduced using software packages, such as XPPAUT.

Rehabilitation with mental practice has similar effects on mobility as rehabilitation with relaxation in people with Parkinson's disease: a multicentre randomised trial

QUESTIONS

Is mental practice embedded in standard physiotherapy compared with relaxation embedded in standard physiotherapy more effective at improving mobility tasks in people with Parkinson's disease in the community? Does disease severity influence the treatment effect?

DESIGN

A multicentre randomised controlled trial.

PARTICIPANTS

People with Parkinson's disease.

INTERVENTION

During a six-week intervention period, both groups received physiotherapy as usual with the addition of either mental practice (experimental group) or relaxation (control group). Imagery skills were taught using a four-step protocol. Movement imagery (in thought) and the performance of motor activities were combined.

OUTCOME MEASURES

Outcomes were assessed at six weeks and three months with: the patient- and therapist-perceived effect on walking performance (visual analogue scale), the Timed Up and Go test, and the 10 m Walk test. Primary analysis was performed using intention-totreat and was repeated as a per-protocol analysis, and as a sub-group analysis of participants with Hoehn and Yahr stage of less than 3. Generalised estimating equations were used to analyse effects.

RESULTS

47 participants were assigned to the control (n = 22) and experimental (n = 25) groups. No effect in favour of the mental practice intervention on any outcome measure could be detected at any of the measurement points. In the sub-group analysis of participants with milder disease, the experimental group improved more than the control group but this was not statistically significant.

CONCLUSION

In this study, we did not find differences between embedded mental practice and relaxation with current standard of care.

TRIAL REGISTRATION

Nederlands Trial Register: NTR1735.

Feasibility of a mental practice intervention in stroke patients in nursing homes; a process evaluation

Background

Within a multi-centre randomised controlled trial in three nursing homes, a process evaluation of a mental practice intervention was conducted. The main aims were to determine if the intervention was performed according to the framework and to describe the therapists' and participants' experiences with and opinions on the intervention.

Methods

The six week mental practice intervention was given by physiotherapists and occupational therapists in the rehabilitation teams and consisted of four phases: explanation of imagery, teaching patients how to use imagery, using imagery as part of therapy, and facilitating the patient in using it alone and for new tasks. It had a mandatory and an optional part. Data were collected by means of registration forms, pre structured patient files, patient logs and self-administered questionnaires.

Results

A total of 14 therapists and 18 patients with stroke in the sub acute phase of recovery were involved. Response rates differed per assessment (range 57-93%). Two patients dropped out of the study (total n = 16). The mandatory part of the intervention was given to 11 of 16 patients: 13 received the prescribed amount of mental practice and 12 practiced unguided outside of therapy. The facilitating techniques of the optional part of the framework were partly used. Therapists were moderately positive about the use of imagery in this specific sample. Although it was more difficult for some patients to generate images than others, all patients were positive about the intervention and reported perceived short term benefits from mental practice.

Conclusions

The intervention was less feasible than we hoped. Implementing a complex therapy delivered by existing multi-professional teams to a vulnerable population with a complex pathology poses many challenges.