Motor imagery beyond the motor repertoire: Activity in the primary visual cortex during kinesthetic motor imagery of difficult whole body movements

Enhancing the quality of kinesthetic motor imagery for complex motor skills through simulated muscle activation color visualization: Evidence from time-frequency and functional connectivity analyses

It is well established that providing visual guidance within demonstration models positively influences the quality of kinesthetic motor imagery (kMI) for complex motor skills. Given that action execution and kMI share several underlying mechanisms, we hypothesize that color-coded visual cues indicating muscle activation in demonstration models can enhance the quality of kMI in the acquisition of complex motor skills. To test this hypothesis. We employed AnyBody Modeling System to develop demonstration model videos of complex motor skills. Thirty participants (mean age = 20.3 ± 0.6 years; 7 men and 8 women per group) were assigned to an experimental group, which engaged in kMI after viewing demonstration videos supplemented with simulated muscle activation color cues, or to a control group, which performed kMI following videos without such cues. All participants scored above 5 on the Motor Imagery Questionnaire-2 (MIQ-2). The vividness of kMI was assessed using the Vividness of Motor Imagery Questionnaire-2 (VMIQ-2). A 64-channel EEG cap was utilized for data acquisition. Changes in alpha and beta range oscillations during kMI were examined, and region of interest (ROI) analysis was conducted to extract the correlation coefficient matrix among kMI-related subcortical nuclei. Our results demonstrated that the vividness of kMI in the experimental group was significantly higher than that in the control group by 19.9 % (P < 0.05). Conversely, alpha event-related synchronization (ERS) in the parietal and occipital regions, as well as ERS in the frontal, central, and temporal regions, were significantly lower in the experimental group compared to the control group. The source-functional connectivity results revealed that the primary differences between the experimental and control groups were concentrated between the left V1 and right V1, as well as among the posterior parietal cortex (PPC), dorsolateral prefrontal cortex (DLPFC), and primary motor cortex (M1). In conclusion, the demonstration model, which incorporates simulated muscle activation and color visualization, enhances the vividness of kMI in complex motor skills. This enhancement is associated with the selective inhibition of the frontal, central, and temporal brain regions, the activation of the occipital and parietal regions within brain rhythmic activity, and increased information flow between the occipital-parietal and frontal-parietal brain regions.

Evidence for the dependence of visual and kinesthetic motor imagery on isolated visual and motor practice

Motor imagery (MI) is a cognitive process believed to rely on the representation developed through experience. The equivalence between MI and execution has been questioned and the relationship between experience types and MI is unclear. We tested how observational and physical practice of hand gesture sequences impacted visual and kinesthetic MI and transfer to the unpracticed effector. Three groups (n = 22/gp.); no-vision physical practice, observational practice and no-practice control, practiced and visually and kinesthetically imagined performing the sequences. MI was assessed using mental chronometry, a movement time (MT) congruency measure and subjective ratings. Physical practice improved kinesthetic MI ratings and observational practice improved visual MI ratings. Contrary to predictions, physical practice did not enhance timing congruency. Imagined MTs were longer in transfer after physical practice, suggesting MI was not based on the same representation. These data question ideas of equivalence, with poor temporal matching after no-vision physical practice.

White matter disconnection impacts proprioception post-stroke

Proprioceptive impairments occur in approximately 50-64% of people following stroke. While much is known about the grey matter structures underlying proprioception, our understanding of the white matter correlates of proprioceptive impairments is less well developed. It is recognised that behavioural impairments post-stroke are often the result of disconnection between wide-scale brain networks, however the disconnectome associated with proprioception post-stroke is unknown. In the current study, white matter disconnection was assessed in relation to performance on a robotic arm position matching (APM) task. Neuroimaging and robotic assessments of proprioception were collected for 203 stroke survivors, approximately 2-weeks post-stroke. The robotic assessment was performed in a KINARM Exoskeleton robotic device and consisted of a nine-target APM task. First, the relationship between white matter tract lesion load and performance on the APM task was assessed. Next, differences in the disconnectome between participants with and without impairments on the APM task were examined. Greater lesion load to the superior longitudinal fasciculus (SLF II and III), arcuate fasciculus (all segments) and fronto-insular tracts were associated with worse APM task performance. In those with APM task impairments, there was, additionally, disconnection of the posterior corpus callosum, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus and optic radiations. This study highlights an important perisylvian white matter network supporting proprioceptive processing in the human brain. It also identifies white matter tracts, important for relaying proprioceptive information from parietal and frontal brain regions, that are not traditionally considered proprioceptive in nature.

Early sleep after action observation plus motor imagery improves gait and balance abilities in older adults

Action observation plus motor imagery (AOMI) is a rehabilitative approach to improve gait and balance performance. However, limited benefits have been reported in older adults. Early sleep after motor practice represents a strategy to enhance the consolidation of trained skills. Here, we investigated the effects of AOMI followed by early sleep on gait and balance performance in older adults. Forty-five older adults (mean age: 70.4 ± 5.2 years) were randomized into three groups performing a 3-week training. Specifically, AOMI-sleep and AOMI-control groups underwent observation and motor imagery of gait and balance tasks between 8:00 and 10:00 p.m. or between 8:00 and 10:00 a.m. respectively, whereas Control group observed landscape video-clips. Participants were assessed for gait performance, static and dynamic balance and fear of falling before and after training and at 1-month follow-up. The results revealed that early sleep after AOMI training sessions improved gait and balance abilities in older adults compared to AOMI-control and Control groups. Furthermore, these benefits were retained at 1-month after the training end. These findings suggested that early sleep after AOMI may represent a safe and easy-applicable intervention to minimize the functional decay in older adults.

Handedness effects on imagery of dominant- versus non-dominant-hand movements: An electroencephalographic investigation

Mental representations of our bodies are thought to influence how we interact with our surroundings. We can examine these mental representations through motor imagery, the imagination of movement using scalp EEG recordings. The visual modality of motor imagery emphasises 'seeing' the imagined movement and is associated with increased activity in the alpha rhythm (8-14 Hz) measured over the occipital regions. The kinaesthetic modality emphasises 'feeling' the movement and is associated with decreased activity in the mu rhythm (8-14 Hz) measured over the sensorimotor cortices. These two modalities can be engaged in isolation or together. We recorded EEG activity while 37 participants (17 left-hand dominant) completed an objective hand motor imagery task. Left-handers exhibited significant activity differences between occipital and motor regions only during imagery of right-hand (non-dominant-hand) movements. This difference was primarily driven by less oscillatory activity in the mu rhythm, which may reflect a shift in imagery strategy wherein participants placed more effort into generating the kinaesthetic sensations of non-dominant-hand imagery. Spatial features of 8-14 Hz activity generated from principal component analysis (PCA) provide further support for a strategy shift. Right-handers also exhibited significant differences between alpha and mu activity during imagery of non-dominant movements. However, this difference was not primarily driven by either rhythm, and no differences were observed in the group's PCA results. Together, these findings indicate that individuals imagine movement differently when it involves their dominant versus non-dominant hand, and left-handers may be more flexible in their motor imagery strategies.

The Neuroscience of Dance: A Conceptual Framework and Systematic Review

Ancient and culturally universal, dance pervades many areas of life and has multiple benefits. In this article, we provide a conceptual framework and systematic review, as a guide for researching the neuroscience of dance. We identified relevant articles following PRISMA guidelines, and summarised and evaluated all original results. We identified avenues for future research in: the interactive and collective aspects of dance; groove; dance performance; dance observation; and dance therapy. Furthermore, the interactive and collective aspects of dance constitute a vital part of the field but have received almost no attention from a neuroscientific perspective so far. Dance and music engage overlapping brain networks, including common regions involved in perception, action, and emotion. In music and dance, rhythm, melody, and harmony are processed in an active, sustained pleasure cycle giving rise to action, emotion, and learning, led by activity in specific hedonic brain networks. The neuroscience of dance is an exciting field, which may yield information concerning links between psychological processes and behaviour, human flourishing, and the concept of eudaimonia.

Recognizable Rehabilitation Movements of Multiple Unilateral Upper Limb: an fMRI Study of Motor Execution and Motor Imagery

BACKGROUND

This paper presents a study investigating the recognizability of multiple unilateral upper limb movements in stroke rehabilitation.

METHODS

A functional magnetic experiment is employed to study motor execution (ME) and motor imagery (MI) of four movements for the unilateral upper limb: hand-grasping, hand-handling, arm-reaching, and wrist-twisting. The functional magnetic resonance imaging (fMRI) images of ME and MI tasks are statistically analyzed to delineate the region of interest (ROI). Then parameter estimation associated with ROIs for each ME and MI task are evaluated, where differences in ROIs for different movements are compared using analysis of covariance (ANCOVA).

RESULTS

All movements of ME and MI tasks activate motor areas of the brain, and there are significant differences (p<0.05) in ROIs evoked by different movements. The activation area is larger when executing the hand-grasping task instead of the others.

CONCLUSION

The four movements we propose can be adopted as MI tasks, especially for stroke rehabilitation, since they are highly recognizable and capable of activating more brain areas during MI and ME.

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.

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

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

Neural Activity During Imagery Supports Three Imagery Abilities as Measured by the Movement Imagery Questionnaire-3

Self-report and neural data were examined in 14 right-handed college-age males screened from a pool of 200 to verify neural activity during imagery and that the neural activity (area of brain) varies as a function of the imagery type. Functional magnetic resonance imaging data collected during real-time imagery of the three Movement Imagery Questionnaire-3 abilities indicated frontal areas, motor areas, and cerebellum active during kinesthetic imagery, motor areas, and superior parietal lobule during internal visual imagery, and parietal lobule and occipital cortex during external visual imagery. Central and imagery-specific neural patterns were found providing further biological validation of kinesthetic, internal visual, and external visual complementing results on females. Next, research should (a) compare neural activity between male participants screened by self-reported imagery abilities to determine if good imagers have more efficient neural networks than poor imagers and (b) determine if there is a statistical link between participants' neural activity during imagery and self-report Movement Imagery Questionnaire-3 scores.

Effect of skill proficiency on motor imagery ability between amateur dancers and non-dancers

Evidence has shown that athletes with high motor skill proficiency possess higher motor imagery ability than those with low motor skill proficiency. However, less is known whether this superiority in motor imagery ability emerges over amateur athletes. To address the issue, the present study aimed to investigate the individual differences in motor imagery ability between amateur dancers and non-dancers. Forty participants completed a novel dance movement reproduction task and measures of the vividness of visual imagery questionnaire (VVIQ) and the vividness of motor imagery questionnaire (VMIQ). The results showed that, relative to non-dancers, amateur dancers had higher ability of motor imagery to reproduce the lower-limb and upper-limb dance movements during the dance movement reproduction task. Besides, amateur dancers displayed higher abilities of the visual motor imagery and the kinesthetic imagery, but comparable visual imagery ability as the non-dancers. These findings suggest that the mental representation of motors but not the visual is affected by the motor skill levels, due to the motor imagery practice in sports amateurs.

Decoding of Motor Imagery Involving Whole-body Coordination

The present study investigated whether different types of motor imageries can be classified based on the location of the activation peaks or the multivariate pattern analysis (MVPA) of functional magnetic resonance imaging (fMRI) and compared the difference between visual motor imagery (VI) and kinesthetic motor imagery (KI). During fMRI scanning sessions, 25 participants imagined four movements included in the Motor Imagery Questionnaire-Revised (MIQ-R): knee lift, jump, arm movement, and waist bend. These four imagined movements were then classified based on the peak location or the patterns of fMRI signal values. We divided the participants into two groups based on whether they found it easier to generate VI (VI group, n = 10) or KI (KI group, n = 15). Our results show that the imagined movements can be classified using both the location of the activation peak and the spatial activation patterns within the sensorimotor cortex, and MVPA performs better than the activation peak classification. Furthermore, our result reveals that the KI group achieved a higher MVPA decoding accuracy within the left primary somatosensory cortex than the VI group, suggesting that the modality of motor imagery differently affects the classification performance in distinct brain regions.

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.

Translation and Validation of the Spanish Movement Imagery Questionnaire Revised Second Version (MIQ-RS)

BACKGROUND

Motor imagery, which emphasizes mental rehearsal of motor skills to improve function, is frequently used in clinical practice. Because of its increasing use, reliable and valid tools are necessary to evaluate motor imagery abilities. However, there are few questionnaires translated and validated into Spanish language.

OBJECTIVE

To translate, transculturally adapt, and validate the Spanish version of the Movement Imagery Questionnaire-Revised Second Version (MIQ-RS).

DESIGN

A single-center observational study.

SETTING

University community.

PARTICIPANTS

One hundred fifty-five healthy participants were recruited.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Spanish translation of the MIQ-RS and psychometric performances of the questionnaire were tested using concurrent-criterion and content validity, construct validity, internal consistency, and test-rest reliability. Internal consistency, concurrent-criterion validity, construct validity, and test-rest reliability were assessed with Cronbach´s alpha, Spearman´s correlation coefficient, confirmatory factor analysis, and intraclass correlation coefficient (ICC), respectively.

RESULTS

Results showed satisfactory internal consistency (Cronbach α = 0.90), test-rest reliability (ICC for visual items = 0.844 and for kinesthetic items = 0.70) and content and criterion-concurrent validity (Spearman´s correlation coefficient for visual items, 0.60 and for kinesthetic items, 0.81) of the MIQ-RS Spanish version. The two-factor structure was supported by confirmatory factor analysis. Statistically significant gender differences were observed in mean kinesthetic motor imagery scores and in mean visual motor imagery scores according to sports practice. No significant differences for gender, age, and sports, musical, and dance practice were reported.

CONCLUSIONS

The Spanish version of the MIQ-RS is a valid and reliable tool to assess motor imagery abilities in healthy young people.

Task-independent Electrophysiological Correlates of Motor Imagery Ability from Kinaesthetic and Visual Perspectives

Motor imagery (MI) ability is highly subjective, as indicated by the individual scores of the MIQ-3 questionnaire, and poor imagers compensate for the difficulty in performing MI with larger cerebral activations, as demonstrated by MI studies involving hands/limbs. In order to identify general, task-independent MI ability correlates, 16 volunteers were stratified with MIQ-3. The scores in the kinaesthetic (K) and 1st-person visual (V) perspectives were associated with EEG patterns obtained during K-MI and V-MI of the same complex MIQ-3 movements during these MI tasks (Spearman's correlation, significance at <0.05, SnPM corrected). EEG measures were relative to rest (relaxation, closed eyes), and based on six electrode clusters both for band spectral content and connectivity (Granger causality). Lower K-MI ability was associated with greater theta decreases during tasks in fronto-central clusters and greater inward information flow to prefrontal clusters for theta, high alpha and beta bands. On the other hand, power band relative decreases were associated with V-MI ability in fronto-central clusters for low alpha and left fronto-central and both centro-parietal clusters for beta bands. The results thus suggest different computational mechanisms for MI-V and MI-K. The association between low alpha/beta desynchronization and V-MIQ scores and between theta changes and K-MIQ scores suggest a cognitive effort with greater cerebral activation in participants with lower V-MI ability. The association between information flow to prefrontal hub and K-MI ability suggest the need for a continuous update of information to support MI-related executive functions in subjects with poor K-MI ability.

Subjective vividness of motor imagery has a neural signature in human premotor and parietal cortex

Motor imagery (MI) is the process in which subjects imagine executing a body movement with a strong kinesthetic component from a first-person perspective. The individual capacity to elicit such mental images is not universal but varies within and between subjects. Neuroimaging studies have shown that these inter-as well as intra-individual differences in imagery quality mediate the amplitude of neural activity during MI on a group level. However, these analyses were not sensitive to forms of representation that may not map onto a simple modulation of overall amplitude. Therefore, the present study asked how far the subjective impression of motor imagery vividness is reflected by a spatial neural code, and how patterns of neural activation in different motor regions relate to specific imagery impressions. During fMRI scanning, 20 volunteers imagined three different types of right-hand actions. After each imagery trial, subjects were asked to evaluate the perceived vividness of their imagery. A correlation analysis compared the rating differences and neural dissimilarity values of the rating groups separately for each region of interest. Results showed a significant positive correlation in the left vPMC and right IPL, indicating that these regions particularly reflect perceived imagery vividness in that similar rated trials evoke more similar neural patterns. A decoding analysis revealed that the vividness of the motor image related systematically to the action specificity of neural activation patterns in left vPMC and right SPL. Imagined actions accompanied by higher vividness ratings were significantly more distinguishable within these areas. Altogether, results showed that spatial patterns of neural activity within the human motor cortices reflect the individual vividness of imagined actions. Hence, the findings reveal a link between the subjective impression of motor imagery vividness and objective physiological markers.

Effect of fine and gross motor training or motor imagery, delivered via novel or routine modes, on cognitive function

There is extensive literature linking motor activity to cognitive effects at various stages in life, promoting both development and the reduction of aging associated pathologies. It is unclear whether the benefits of this activity on the cognitive level are associated with brain functions that are necessary for their performance or recurrence of activity or type of activity itself. The aim of this study was to evaluate whether the type of motor activity (fine, gross, and motor imagery) in two modes (novel and routine) can affect cognitive functions such as attention, executive functions, and praxis in college students. A 2 × 3 factorial design with repeated measures was used without a control group and pre- and post-training evaluation. Fifty-three young people (14 men and 39 women) participated, with mean age of 18.94 years (SD = 1.61 years) and were divided into six groups. Each of the groups performed relevant training 20 minutes per day for five days depending on the group. Measures were taken pre and post-training for attention tests, attention span, working memory, visual constructive skills, procedural memory, and motor skills. The results show a "learning effect" from the exposure to the tests in measurements after training. It was also found that between groups, there is a difference in some of the variables of procedural memory (number of errors) and working memory. More extensive training could better reflect the effects of the training, and longitudinal evaluation could show the rate of change of functions. The main clinical implication could be the evaluation of training programs for recovery and motor training in cerebral plasticity having effect on the cognitive aspects.

The format of mental imagery: from a critical review to an integrated embodied representation approach

The issue of the format of mental imagery is still an open debate. The classical analogue (depictive)-propositional (descriptive) debate has not provided definitive conclusions. Over the years, the debate has shifted within the frame of the embodied cognition approach, which focuses on the interdependence of perception, cognition and action. Although the simulation approach still retains the concept of representation, the more radical line of the embodied cognition approach emphasizes the importance of action and clearly disregards the concept of representation. In particular, the enactive approach focuses on motor procedures that allow the body to interact with the environment, whereas the sensorimotor approach focuses on the possession and exercise of sensorimotor knowledge about how the sensory input changes as a function of movement. In this review, the embodied approaches are presented and critically discussed. Then, in an attempt to show that the format of mental imagery varies according to the ability and the strategy used to represent information, the role of individual differences in imagery ability (e.g., vividness and expertise) and imagery strategy (e.g., object vs. spatial imagers) is reviewed. Since vividness is mainly associated with perceptual information, reflecting the activation level of specific imagery systems, whereas the preferred strategy used is mainly associated with perceptual (e.g., object imagery) or amodal and motor information (e.g., spatial imagery), the format of mental imagery appears to be based on dynamic embodied representations, depending on imagery abilities and imagery strategies.

Vividness and accuracy: Two independent aspects of motor imagery

Motor imagery is the mental execution of an action without any actual movement. Although numerous studies have utilized questionnaires to evaluate the vividness of motor imagery, it remains unclear whether it is related to the accuracy of motor imagery. To examine the relationship between vividness and accuracy, we investigated brain activity during kinesthetic and visual motor imagery, by using a novel sequential finger-tapping task. We estimated accuracy by measuring the fidelity of the actual performance and evaluated vividness by using a visual analog scale. We found that accuracy of visual motor imagery was correlated with the activity in the left visual cortex, as well as with bilateral sensorimotor regions. In contrast, vividness of visual motor imagery was associated with the activity in the right orbitofrontal cortex. However, there was no correlation in the brain activity between the right orbitofrontal cortex and visuomotor regions or between vividness and accuracy of motor imagery. In addition, we did not find any correlation in the kinesthetic imagery condition. We conclude that vividness of visual motor imagery is associated with the right orbitofrontal cortex and is independent of processes occurring in sensorimotor regions, which would be responsible for the accuracy of visual motor imagery.

Visual and Motor Recovery After "Cognitive Therapeutic Exercises" in Cortical Blindness: A Case Study

BACKGROUND AND PURPOSE

Spontaneous visual recovery is rare after cortical blindness. While visual rehabilitation may improve performance, no visual therapy has been widely adopted, as clinical outcomes are variable and rarely translate into improvements in activities of daily living (ADLs). We explored the potential value of a novel rehabilitation approach "cognitive therapeutic exercises" for cortical blindness.

CASE DESCRIPTION

The subject of this case study was 48-year-old woman with cortical blindness and tetraplegia after cardiac arrest. Prior to the intervention, she was dependent in ADLs and poorly distinguished shapes and colors after 19 months of standard visual and motor rehabilitation. Computed tomographic images soon after symptom onset demonstrated acute infarcts in both occipital cortices.

INTERVENTION

The subject underwent 8 months of intensive rehabilitation with "cognitive therapeutic exercises" consisting of discrimination exercises correlating sensory and visual information.

OUTCOMES

Visual fields increased; object recognition improved; it became possible to watch television; voluntary arm movements improved in accuracy and smoothness; walking improved; and ADL independence and self-reliance increased. Subtraction of neuroimaging acquired before and after rehabilitation showed that focal glucose metabolism increases bilaterally in the occipital poles.

DISCUSSION

This study demonstrates feasibility of "cognitive therapeutic exercises" in an individual with cortical blindness, who experienced impressive visual and sensorimotor recovery, with marked ADL improvement, more than 2 years after ischemic cortical damage.Video Abstract available for additional insights from the authors (see Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A173).

Motor Imagery as a Function of Disease Severity in Multiple Sclerosis: An fMRI Study

Motor imagery (MI) is defined as mental execution without any actual movement. While healthy adults usually show temporal equivalence, i.e., isochrony, between the mental simulation of an action and its actual performance, neurological disorders are associated with anisochrony. Unlike in patients with stroke and Parkinson disease, only a few studies have investigated differences of MI ability in multiple sclerosis (MS). However, the relationship among disease severity, anisochrony and brain activation patterns during MI has not been investigated yet. Here, we propose to investigate MI in MS patients using fMRI during a behavioral task executed with dominant/non-dominant hand and to evaluate whether anisochrony is associated with disease severity. Thirty-seven right-handed MS patients, 17 with clinically isolated syndrome (CIS) suggestive of MS and 20 with relapsing-remitting MS (RR-MS) and 20 right-handed healthy controls (HC) underwent fMRI during a motor task consisting in the actual or imaged movement of squeezing a foam ball with the dominant and non-dominant hand. The same tasks were performed outside the MRI room to record the number of actual and imagined ball squeezes, and calculate an Index of performance (IP) based on the ratio between actual and imagined movements. IP showed that a progressive loss of ability in simulating actions (i.e., anisochrony) more pronounced for non-dominant hand, was found as function of the disease course. Moreover, anisochrony was associated with activation of occipito-parieto-frontal areas that were more extensive at the early stages of the disease, probably in order to counteract the changes due to MS. However, the neural engagement of compensatory brain areas becomes more difficult with more challenging tasks, i.e., dominant vs. non-dominant hand, with a consequent deficit in behavioral performance. These results show a strict association between MI performance and disease severity, suggesting that, at early stages of the disease, anisochrony in MI could be considered as surrogate behavioral marker of MS severity.