Movement Imagery Research Articles

Eye gaze metrics reflect a shared motor representation for action observation and movement imagery

Action observation (AO) and movement imagery (MI) have been reported to share similar neural networks. This study investigated the congruency between AO and MI using the eye gaze metrics, dwell time and fixation number. A simple reach–grasp–place arm movement was observed and, in a second condition, imagined where the movement was presented from the first person perspective (1PP) and the third person perspective (3PP). Dwell time and number of fixations were calculated for whole scene and regions of interest (ROIs). For whole scene, no significant differences were found in the number of fixations for condition (AO, MI) or perspective. Dwell time, however, was significantly longer in AO than MI. For ROIs, the number of fixations was significantly greater in 1PP than 3PP. The data provide support for congruence between motor simulation states but also indicate some functional differences.

Neurofeedback Using Real-Time Near-Infrared Spectroscopy Enhances Motor Imagery Related Cortical Activation

Accumulating evidence indicates that motor imagery and motor execution share common neural networks. Accordingly, mental practices in the form of motor imagery have been implemented in rehabilitation regimes of stroke patients with favorable results. Because direct monitoring of motor imagery is difficult, feedback of cortical activities related to motor imagery (neurofeedback) could help to enhance efficacy of mental practice with motor imagery. To determine the feasibility and efficacy of a real-time neurofeedback system mediated by near-infrared spectroscopy (NIRS), two separate experiments were performed. Experiment 1 was used in five subjects to evaluate whether real-time cortical oxygenated hemoglobin signal feedback during a motor execution task correlated with reference hemoglobin signals computed off-line. Results demonstrated that the NIRS-mediated neurofeedback system reliably detected oxygenated hemoglobin signal changes in real-time. In Experiment 2, 21 subjects performed motor imagery of finger movements with feedback from relevant cortical signals and irrelevant sham signals. Real neurofeedback induced significantly greater activation of the contralateral premotor cortex and greater self-assessment scores for kinesthetic motor imagery compared with sham feedback. These findings suggested the feasibility and potential effectiveness of a NIRS-mediated real-time neurofeedback system on performance of kinesthetic motor imagery. However, these results warrant further clinical trials to determine whether this system could enhance the effects of mental practice in stroke patients.

Close Range Stereophotogrammetry and Video Imagery Analyses in Soil Ecohydrology Modelling

AbstractEcohydrology is an emerging discipline in the environmental sciences. Soil micro‐relief is of relevance to various ecohydrological processes such as rainwater redistribution, seed displacement through water runoff, water erosion and plant competition for water. Mechanical–optical methods to characterise the soil surface and its incidence in these processes are time consuming and can produce modifications of soil relief. This research explores a methodology combining non‐contact techniques (close range stereophotogrammetry and geostatistical modelling) for microtopographic description with video imagery analysis to formulate quantitative determination of surface water movement and infiltration in undisturbed field plots. The numerical quality of the results obtained was tested with ad hoc laboratory models representing various elementary landforms (basin, hill and ridge), as well as with infiltration runoff experiments in undisturbed field plots. The requirements to define a minimum set of properly oriented digital images to attain target precision thresholds in modelling soil microtopography for ecohydrological applications are shown as well as the conditions and experimental arrangement to obtain adequate video imagery of water movement on the soil surface. The use of geostatistical algorithms to analyse ecohydrological processes occurring at the soil surface is illustrated with results obtained from field plots. The methodology presented serves to characterise and quantify water‐related ecological processes occurring at the soil surface while preserving undisturbed soil conditions. Potential applications are in ecohydrology, soil erosion science and environmental material transport studies.

Motor Imagery Ability in Patients With Traumatic Brain Injury

Oostra KM, Vereecke A, Jones K, Vanderstraeten G, Vingerhoets G. Motor imagery ability in patients with traumatic brain injury. ObjectiveTo assess motor imagery (MI) ability in patients with moderate to severe traumatic brain injury (TBI). DesignProspective, cohort study. SettingUniversity hospital rehabilitation unit. ParticipantsPatients with traumatic brain injury (mean coma duration, 18d) undergoing rehabilitation (n=20) and healthy controls (n=17) matched for age and education level. InterventionsNot applicable. Main Outcome MeasuresThe vividness of MI was assessed using a revised version of the Movement Imagery Questionnaire—Revised second version (MIQ-RS); the temporal features were assessed using the time-dependent motor imagery (TDMI) screening test, the temporal congruence test, and a walking trajectory imagery test; and the accuracy of MI was assessed using a mental rotation test. ResultsThe MIQ-RS revealed a decrease of MI vividness in the TBI group. An increasing number of stepping movements was observed with increasing time periods in both groups during the TDMI screening test. The TBI group performed a significantly smaller number of imagery movements in the same movement time. The temporal congruence test revealed a significant correlation between imagery and actual stepping time in both groups. The walking trajectory test revealed an increase of the imagery and actual walking time with increasing path length in both groups, but the ratio of imaginary walking over actual walking time was significantly greater than 1 in the TBI group. Results of the hand mental rotation test indicated significant effects of rotation angles on imagery movement times in both groups, but rotation time was significantly slower in the TBI group. ConclusionsOur patients with TBI demonstrated a relatively preserved MI ability indicating that MI could be used to aid rehabilitation and subsequent functional recovery.

Abstract 3317: Neurofeedback Enhance The Efficacy Of Mental Practice With Motor Imagery In Post-acute Stroke Victims: A Pilot Study.

Background/Objective: Accumulating evidence indicates that motor imagery and motor execution share common neural networks. Accordingly, mental practice with motor imagery has been implemented in the rehabilitation regimes of stroke patients. However, several studies investigating the efficacy of mental practice with motor imagery revealed inconsistent results. We hypothesized that difficulty for monitoring effort and compliance during motor imagery would cause inconsistency, and feedback of cortical activities (neurofeedback) may enhance the efficacy of mental practice with motor imagery. Methods: We recruited 15 post-acute hemiparetic patients with subcortical stroke (9 males, age: 58.7 ± 6.8 years). Averaged duration from onset was 132.1 ± 38.5 days. In addition to the usual training sessions of up to 180 min per day, all participants received 20 min session of the mental practice with motor imagery 3 times a week for 2 weeks. Mental practice consisted of video based motor imagery for 10 min followed by motor imagery with neurofeedback for 10 min. Participants were randomly assigned to the Real group or the Sham group. During neurofeedback, participants performed 16 repetitions of 5 sec motor imagery task, and cortical activation from the contralateral motor cortex was measured by a near infrared spectroscopy (NIRS). In the Real group, cortical activation processed in a real-time fashion was feedbacked, and irrelevant randomized value was feedbacked in the Sham group. Primary outcome measure was the finger and arm subscales of the Fugl-Meyer assessment (FMA), and the action research arm test (ARAT) was also assessed. Upper limb function was assessed at before, immediately after, and two weeks after the mental practice. Motor activity log (MAL), and kinesthetic and visual motor imagery questionnaire was also assessed before and after mental practice. We used repeated measures ANOVA to test the effect of mental practice and neurofeedback. For evaluation of the motor imagery related cortical activation changes during mental practice, contrast between cortical activation in the first and last session was assessed and unpaired t-test for group difference was performed. Results: In the finger function subscale in FMA, there was significant effect of time (F2,13=25.622, p<0.001) and interaction between time and group (F2,13=10.689, p<0.005) with more functional gain in the Real group. Mental practice also affected other outcome measures including arm subscale of FMA, ARAT, and MAL, but there was no significant interaction. Enhancement of finger movement imagery related cortical activation was significantly greater in the Real group than the Sham group (t88 =2.046 p<0.05). Conclusion: Our results imply that NIRS mediated neurofeedback has a positive add-on effect on the efficacy of mental practice with motor imagery and its related cortical activation.

Age Differences in the Vividness of Youth Sport Performers’ Imagery Ability

Abstract The Vividness of Movement Imagery Questionnaire-2 (VMIQ-2; Roberts et al., 2008) is a recent addition to tools developed for investigating movement imagery ability. To date, few studies have adopted this measure within youth sport cohorts, as a result little is known about the vividness aspect of imagery ability in samples of 21 years of age and younger. Participants included 169 youth sport performers between 12 and 21 years of age (M = 16.62, SD = 3.02), representing 14 sports at 4 levels of competitive engagement. Participants completed the VMIQ-2 and were grouped according to age, competitive level, and gender. Significant differences between the VMIQ-2’s subscales were demonstrated with participants recording greatest imagery vividness for internal visual imagery and least vividness for external visual imagery. Significant age differences existed for kinesthetic imagery between the 12-13 and 20-21 age groups, with the 20-21 group recording greater imagery vividness than their younger counterparts. The results demonstrate age can influence imagery vividness with youth sport performers recording higher vividness for internal visual imagery compared to kinesthetic and external visual imagery. Future investigations should attempt to determine why age cohort differences in vividness of imagery occur.

Mental Practice is Modifiable: Changes in Perspective Maintenance and Vividness Post-Stroke

Abstract This exploratory study investigated effects of a mental practice (MP) intervention on imagery vividness and perspective maintenance in post-stroke subjects. Additionally, the relationship between internal and external imagery vividness and kinesthetic imagery was examined. Data were drawn from 17 persons participating in a RCT investigating the effects of perspective use during MP on post-stroke recovery. The Vividness of Movement Imagery Questionnaire-2 (VMIQ-2) and a self-report perspective rating scale were used to examine changes in vividness and perspective maintenance, respectively. Findings indicate improvements in vividness were most evident in those with the weakest initial ability. Perspective maintenance improved significantly from the first score to the last for all groups. Visual imagery vividness was strongly related to kinesthetic imagery regardless of imagery perspective. Preliminary findings suggest certain aspects of imagery ability can be improved with practice post-stroke.

Further Validation and Development of the Movement Imagery Questionnaire

This research validated and extended the Movement Imagery Questionnaire- Revised (MIQ-R; Hall & Martin, 1997). Study 1 (N = 400) examined the MIQ-R's factor structure via multitrait-multimethod confirmatory factor analysis. The questionnaire was then modified in Study 2 (N = 370) to separately assess the ease of imaging external visual imagery and internal visual imagery, as well as kinesthetic imagery (termed the Movement Imagery Questionnaire-3; MIQ-3). Both Studies 1 and 2 found that a correlated-traits correlated-uniqueness model provided the best fit to the data, while displaying gender invariance and no significant differences in latent mean scores across gender. Study 3 (N = 97) demonstrated the MIQ-3's predictive validity revealing the relationships between imagery ability and observational learning use. Findings highlight the method effects that occur by assessing each type of imagery ability using the same four movements and demonstrate that better imagers report greater use of observational learning.

Silent Communication: Toward Using Brain Signals

From the 1980s movie Firefox to the more recent Avatar, popular science fiction has speculated about the possibility of a persons thoughts being read directly from his or her brain. Such braincomputer interfaces (BCIs) might allow people who are paralyzed to communicate with and control their environment, and there might also be applications in military situations wherever silent user-to-user communication is desirable. Previous studies have shown that BCI systems can use brain signals related to movements and movement imagery or attention-based character selection. Although these systems have successfully demonstrated the possibility to control devices using brain function, directly inferring which word a person intends to communicate has been elusive. A BCI using imagined speech might provide such a practical, intuitive device. Toward this goal, our studies to date addressed two scientific questions: (1) Can brain signals accurately characterize different aspects of speech? (2) Is it possible to predict spoken or imagined words or their components using brain signals?

Brain Activity during the Observation, Imagery, and Execution of Tool Use: An fNIRS/EEG Study

This study used a functional near-infrared spectroscopy (fNIRS)/electroencephalogram (EEG) system to investigate brain activity during a daily living situation where subjects are engaged in the observation, imagery, and execution of tool use. The subjects were 24 healthy adults who signed an agreement to participate in the present study. All subjects were right-handed according to the Edinburgh Handedness Inventory. The subjects sat on a chair and participated in the observation, imagery, and execution of chopstick and hammer movements. Each trial consisted of observation, imagery, and execution and the trials were performed in triplicate. The timing protocol was 15.0, 15.0, 15.0, 15.0, and 15.0 s for rest, task, rest, task, and rest, respectively, and brain activity was measured during these periods. fNIRS and EEG were used to measure brain activity. Optical fibers of fNIRS were positioned over the frontoparietal area. Oxyhemoglobin served as a parameter, and NIRS-statistical parametric mapping (SPM) was used for data analysis. EEG measurements were made using 32 electrodes with an international 10–20 system. The event-related desynchronization of the Mu frequency band (8-12 Hz) was calculated by power spectrum analysis. The brain regions activated during the imagery and execution of the chopsticks movement were the dorsolateral prefrontal cortex, inferior frontal gyrus, premotor cortex, and primary somatosensory cortex, while the mu ERD values were obtained under both conditions. The brain regions that were mainly activated under all three conditions of the hammer movement, i.e., observation, imagery, and execution, were the dorsolateral prefrontal cortex, inferior frontal gyrus, and premotor cortex, while the mu ERD values were obtained under all three conditions. These results suggest that brain activity during the observation, imagery, and execution of tool use differed according to the sensory modality linked to a tool.

Effects of Levodopa on Vividness of Motor Imagery in Parkinson Disease

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. 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. 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). 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 Online Envelope Detection Based on Sliding Window ICA and Its Application to Brain-Computer Interface

Independent component analysis(ICA) is an effective spatial filtering method and has promising potentials in the field of brain computer interface(BCI).This paper focuses on the adaptive ICA algorithm based on sliding window,and a novel approach of ICA-based envelope detection is proposed,which is applied to the envelope detection of mu rhythm induced by motor imagination and the corresponding classification algorithm is developed.With this algorithm,the offline and online experiments of BCI of movement imagery are carried out,and the good recognition results are obtained.

The Movement Imagery Questionnaire-Revised, Second Edition (MIQ-RS) Is a Reliable and Valid Tool for Evaluating Motor Imagery in Stroke Populations

Mental imagery can improve motor performance in stroke populations when combined with physical therapy. Valid and reliable instruments to evaluate the imagery ability of stroke survivors are needed to maximize the benefits of mental imagery therapy. The purposes of this study were to: examine and compare the test-retest intra-rate reliability of the Movement Imagery Questionnaire-Revised, Second Edition (MIQ-RS) in stroke survivors and able-bodied controls, examine internal consistency of the visual and kinesthetic items of the MIQ-RS, determine if the MIQ-RS includes both the visual and kinesthetic dimensions of mental imagery, correlate impairment and motor imagery scores, and investigate the criterion validity of the MIQ-RS in stroke survivors by comparing the results to the KVIQ-10. Test-retest analysis indicated good levels of reliability (ICC range: .83–.99) and internal consistency (Cronbach α: .95–.98) of the visual and kinesthetic subscales in both groups. The two-factor structure of the MIQ-RS was supported by factor analysis, with the visual and kinesthetic components accounting for 88.6% and 83.4% of the total variance in the able-bodied and stroke groups, respectively. The MIQ-RS is a valid and reliable instrument in the stroke population examined and able-bodied populations and therefore useful as an outcome measure for motor imagery ability.

Facilitation of Corticospinal Excitability during Motor Imagery of Wrist Movement with Visual or Quantitative Inspection of EMG Activity

The present study investigated facilitation of corticospinal excitability during motor imagery of wrist movement with visual or quantitative inspection of background electromyographic (EMG) activity. Ten healthy participants imagined wrist extension from a first-person perspective in response to a start cue. Transcranial magnetic stimulation was delivered to the motor cortex 2 sec. after the start cue. EMG signals were recorded from the extensor carpi radialis muscle. Trials with background EMG activity were discarded based on visual inspection. Both motor-evoked potential (MEP) and background EMG amplitudes increased during motor imagery. The amount of increase in MEP amplitude was positively correlated with the amount of increase in background EMG amplitude during motor imagery. The statistically significant increase in MEP amplitude during motor imagery disappeared when the effect of muscle activity was statistically eliminated or after trials with background EMG activity were discarded based on strict quantitative criteria. Facilitation of corticospinal excitability during motor imagery of wrist movement depends partially on muscle activity. Discarding background EMG activity during motor imagery based on visual inspection is not sufficient to equalize background EMG amplitude between resting and motor imagery. Discarding trials with background EMG activity through strict quantitative criteria is useful to equalize background EMG amplitude between at rest and during motor imagery.

Abnormal Parietal Function in Conversion Paresis

The etiology of medically unexplained symptoms such as conversion disorder is poorly understood. This is partly because the interpretation of neuroimaging results in conversion paresis has been complicated by the use of different control groups, tasks and statistical comparisons. The present study includes these different aspects in a single data set. In our study we included both normal controls and feigners to control for conversion paresis. We studied both movement execution and imagery, and we contrasted both within-group and between-group activation. Moreover, to reveal hemisphere-specific effects that have not been reported before, we performed these analyses using both flipped and unflipped data. This approach resulted in the identification of abnormal parietal activation which was specific for conversion paresis patients. Patients also showed reduced activity in the prefrontal cortex, supramarginal gyrus and precuneus, including hemisphere-specific activation that is lateralized in the same hemisphere, regardless of right- or left-sided paresis. We propose that these regions are candidates for an interface between psychological mechanisms and disturbed higher-order motor control. Our study presents an integrative neurophysiological view of the mechanisms that contribute to the etiology of this puzzling psychological disorder, which can be further investigated with other types of conversion symptoms.

Effects of Visual Transformation on Object Manipulation in 3D Space

People can effortlessly manipulate the cursor on 2D screen without seeing their hands. What happens in the 3D case? This study is to examine how visual feedback influences the performance of object manipulation in 3D space. In our experiments virtual 3D disks in different orientations were sequentially shown to subjects wearing stereo shutter glasses. Subjects' task was to touch the disks from designated directions with the stylus of a force-feedback device as fast as possible. Three conditions of visual feedbacks were set: (1) the subjects looked down at their hand and the virtual stylus was shown at the location of the actual stylus using a mirror; (2) the subjects looked straight forward and the virtual stylus was translated to the height of eye position; and (3) the subjects looked straight forward as in condition (2) whereas the virtual stylus was shown from the viewpoint of condition (1). The average performance time of condition (1) was shortest whereas that of (3) was in between. The results suggest that mental imagery of hand movement may be constructed from the viewpoint when looking at the hand in current posture, and used for manipulating objects in 3D space when the hand is not visible.

The relationship between corticospinal excitability during motor imagery and motor imagery ability

It is commonly reported that transcranial magnetic stimulation (TMS) of the motor cortex during action observation and motor imagery results in increases in the amplitude of motor evoked potentials (MEPs) in muscles specific to the observed or imagined action. This study aimed to determine whether MEP amplitude was related to the motor imagery ability of participants. Participants were 15 healthy, right-handed adults (five male), with a mean age of 29.7 years. Motor imagery ability was measured using the Vividness of Movement Imagery Questionnaire-2 (VMIQ-2) and a hand rotation task. TMS was delivered during observation and imagery of a finger-thumb opposition sequence and MEPs were measured in the abductor pollicis brevis. Significant increases in MEP amplitude, from baseline, were recorded during observation and imagery conditions. The change in amplitude to both observation and imagery was expressed as a percentage of baseline amplitude. There was a significant correlation between MEP change for the imagery condition and imagery ability, with greater change linked to more vivid images and faster response times. The relationship between MEP change for the observation condition and imagery ability was less salient. This is the first study to show that the strength of corticospinal activation during imagery, which may be a determinant of the effectiveness of imagery training, is related to imagery ability in the general population, and has implications for clinical programs.

The Functional Equivalence Between Movement Imagery, Observation, and Execution Influences Imagery Ability

Based on literature identifying movement imagery, observation, and execution to elicit similar areas of neural activity, research has demonstrated that movement imagery and observation successfully prime movement execution. To investigate whether movement and observation could prime ease of imaging from an external visual-imagery perspective, an internal visual-imagery perspective, and kinesthetic modality, 36 participants (M age = 20.58; SD = 3.11; 18 women and 18 men) completed an adapted version of the Movement Imagery Questionnaire-Revised under four modes of delivery (movement prime, external observation prime, internal observation prime, and image-only). The results revealed that ease of imaging was significantly greater during the movement and observation prime conditions compared to the image-only condition (p < .05). Specifically when priming external visual imagery and internal visual imagery, observation facilitated ease of imaging only when the perspective was congruent with the imagery perspective. The results support the use of movement and observation to facilitate ease of imaging, but highlight the importance of considering the visual perspective when using observation.

Use of movement imagery in neurorehabilitation

Since the beginning of the new millennium, the use of mental practice and movement imagery within several medical professions in rehabilitation and therapy has received an increased attention. Before this introduction in healthcare, the use of movement imagery was mainly researched in sports science. Mental practice is a complex intervention. When a complex intervention is applied in a new target group or population, the intervention is most likely needed to be adjusted, developed, and evaluated. Recently, a dissertation has been published in which the researchers describe their efforts to transfer the use of movement imagery in sports to rehabilitation. This study reports two aspects from this research project: (a) What did the researcher do? (b) What do the results mean for future research? First, however, some background information is given, in which the use of movement imagery in athletes is discussed.

Feature Extraction from Subband Brain Signals and Its Classification

This paper considers both the non-stationarity as well as independence/uncorrelated criteria along with the asymmetry ratio over the electroencephalogram (EEG) signals and proposes a hybrid approach of the signal preprocessing methods before the feature extraction. A filter bank approach of the discrete wavelet transform (DWT) is used to exploit the non-stationary characteristics of the EEG signals and it decomposes the raw EEG signals into the subbands of different center frequencies called as rhythm. A post processing of the selected subband by the AMUSE algorithm (a second order statistics based ICA/BSS algorithm) provides the separating matrix for each class of the movement imagery. In the subband domain the orthogonality as well as orthonormality criteria over the whitening matrix and separating matrix do not come respectively. The human brain has an asymmetrical structure. It has been observed that the ratio between the norms of the left and right class separating matrices should be different for better discrimination between these two classes. The alpha/beta band asymmetry ratio between the separating matrices of the left and right classes will provide the condition to select an appropriate multiplier. So we modify the estimated separating matrix by an appropriate multiplier in order to get the required asymmetry and extend the AMUSE algorithm in the subband domain. The desired subband is further subjected to the updated separating matrix to extract subband sub-components from each class. The extracted subband sub-components sources are further subjected to the feature extraction (power spectral density) step followed by the linear discriminant analysis (LDA).