Implicit and explicit motor imagery ability after SCI: Moving the elbow makes the difference.

Cervical spinal cord injury (SCI) causes dramatic sensorimotor deficits that restrict both activity and participation. Restoring activity and participation requires extensive upper limb rehabilitation focusing elbow and wrist movements, which can include motor imagery. Yet, it remains unclear whether MI ability is impaired or spared after SCI. We investigated implicit and explicit MI ability in individuals with C6 or C7 SCI (SCIC6 and SCIC7 groups), as well as in age- and gender-matched controls without SCI. Inspired by previous studies, implicit MI evaluations involved hand laterality judgments, hand orientation judgments (HOJT) and hand-object interaction judgments. Explicit MI evaluations involved mental chronometry assessments of physically possible or impossible movements due to the paralysis of upper limb muscles in both groups of participants with SCI. HOJT was the paradigm in which implicit MI ability profiles differed the most between groups, particularly in the SCIC6 group who had impaired elbow movements in the horizontal plane. MI ability profiles were similar between groups for explicit MI evaluations, but reflected task familiarity with higher durations in the case of unfamiliar movements in controls or attempt to perform movements which were no longer possible in persons with SCI. Present results, obtained from a homogeneous population of individuals with SCI, suggest that people with long-term SCI rely on embodied cognitive motor strategies, similar to controls. Differences found in behavioral response pattern during implicit MI mirrored the actual motor deficit, particularly during tasks that involved internal representations of affected body parts.

Assessing the implementation of community-based learning in public health: a mixed methods approach.

BACKGROUND: The French government has set up a community-based learning programme on health promotion for undergraduate health students to involve them in key public health objectives. At the University of Lyon, students first underwent formal instruction, including e-learning, lectures, and interactive seminars, and then became health educators for school pupils. The main objective of the present study was to assess the process of implementing this programme during the 2018-2019 academic year. METHODS: The satisfaction and perception of medical and midwife students with community-based learning experiences were assessed by a questionnaire, semi-directive interviews, and observations. Replies to the questionnaire were described by median and interquartile range or by proportion. A paired Wilcoxon-Mann-Whitney test was used to compare self-evaluated students' competence scores before and after the seminars (alpha risk of 5%). Thematic analyses using grounded theory were performed on recorded and transcribed interviews, and on transcribed notes taken during the observations. RESULTS: Over time the students have evolved from a negative perception of the community-based learning to a positive one. The students were mostly satisfied by interactive seminars that allowed them to gain confidence and competencies in health education. Their involvement in the programme increased their self-esteem. They became more aware of their educative responsibilities regarding public health issues as future professionals. CONCLUSIONS: The students had a positive perception of the implementation of a community-based learning programme in our University, as it appeared a pertinent strategy to raise their awareness of prevention and health education issues.

Inconclusive efficacy of intervention on upper-limb function after tetraplegia: A systematic review and meta-analysis.

BACKGROUND: Rehabilitation aims to improve hand-arm function, upper-limb strength, and functional independence that has been impaired by tetraplegia. On the basis of evidence derived from stroke rehabilitation, interventions aiming to increase intensity (i.e., duration and/or number of movements practiced) or alter brain plasticity (including motor imagery, virtual reality, transcranial direct-current or magnetic stimulations; i.e., neuromodulation) are now used during tetraplegic rehabilitation. However, no meta-analysis has investigated the efficacy of these interventions. OBJECTIVE: This systematic review and meta-analysis investigated, separately, the efficacy of these interventions to alter hand-arm function, upper-limb strength, and functional independence of individuals with tetraplegia. METHODS: Two independent reviewers followed the PROSPERO protocol (CRD42018098506) for this systematic review. MEDLINE, PEDro CENTRAL, and SCOPUS databases were searched for reports of randomized controlled trials of individuals with tetraplegia that were published in English. We performed a meta-analysis of intensive versus less intensive interventions and neuromodulation versus sham interventions considering hand-arm function, strength, and functional independence. RESULTS: From 168 records identified, we included 29 studies (all but 1 were single-centre) in the systematic review (647 participants with C2 to T1 tetraplegia [American Spinal Injury Association impairment scale A to D]). Interventions lasted from 66 to 40,320min. Five studies were retained in the intensity meta-analyses and 5 in the neuromodulation meta-analyses. Overall, 3/5 and 1/5 studies had adequate methodology (Cochrane Risk of Bias score ≥6/10). For each outcome, the p-values for the overall effect were>0.05. Heterogeneity was low, but when analyzing intensity, it was moderate for functional independence and high for hand-arm function. Quality of evidence was very low to low. CONCLUSIONS: We can provide no recommendations for using intensive versus less intensive interventions or neuromodulation versus sham during tetraplegia rehabilitation. Further multicentre studies of high methodological quality are required to reduce uncertainty about the efficacy of these interventions.

Limited evidence of physical therapy on balance after stroke: A systematic review and meta-analysis.

BACKGROUND: Stroke results in balance disorders and these directly affect autonomy and quality of life. The purpose of this systematic review and meta-analysis was to determine the efficacy of physical therapy (PT) on balance and postural control after stroke. METHODS: We included all randomized controlled trials assessing the efficacy of PT on balance and postural control in adult patients after stroke without language restriction. Medline, Embase/Scopus, Cochrane Central Register of Controlled Trials, PEDro, Pascal, and Francis databases were searched until January 2019. Primary outcomes were balance (Berg Balance scale and Postural Assessment Scale for Stroke) and postural control with postural deviation or stability measurement in sitting or standing static evaluation. A pair of independent reviewers selected studies, extracted data, and assessed risk of bias. Meta-analyses with subgroups (categories of PT, time post-stroke, and lesion location) and meta-regression (duration of PT) were conducted. RESULTS: A total of 145 studies (n = 5912) were selected from the 13,123 records identified. For balance, evidence was found in favor of the efficacy of functional task-training alone (standardized mean difference 0.39, 95% confidence interval [0.09; 0.68], heterogeneity I2 = 63%) or associated with musculoskeletal intervention and/or cardiopulmonary intervention (0.37, [0.19; 0.55], I2 = 48%), electrostimulation (0.91, [0.49; 1.34], I2 = 52%) immediately after intervention, compared to sham treatment or usual care (ST/UC). For postural deviation eyes open, assistive devices were more effective than no treatment (-0.21, [-0.37; -0.05], I2 = 0%) immediately after intervention; for postural stability eyes open, functional task-training and sensory interventions were more effective than ST/UC (0.97, [0.35; 1.59], I2 = 65% and 0.80, [0.46; 1.13], I2 = 37% respectively) immediately after intervention. CONCLUSIONS: Functional task-training associated with musculoskeletal intervention and/or cardiopulmonary intervention and sensory interventions seem to be immediately effective in improving balance and postural stability, respectively. The heterogeneity of PT and the weak methodological quality of studies limited the interpretation and the confidence in findings.

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.

Using eye movements to explore mental representations of space.

Visual mental imagery is a cognitive experience characterised by the activation of the mental representation of an object or scene in the absence of the corresponding stimulus. According to the analogical theory, mental representations have a pictorial nature that preserves the spatial characteristics of the environment that is mentally represented. This cognitive experience shares many similarities with the experience of visual perception, including eye movements. The mental visualisation of a scene is accompanied by eye movements that reflect the spatial content of the mental image, and which can mirror the deformations of this mental image with respect to the real image, such as asymmetries or size reduction. The present article offers a concise overview of the main theories explaining the interactions between eye movements and mental representations, with some examples of the studies supporting them. It also aims to explain how ocular-tracking could be a useful tool in exploring the dynamics of spatial mental representations, especially in pathological situations where these representations can be altered, for instance in unilateral spatial neglect.

Spontaneous ocular positioning during visual imagery in patients with hemianopia and/or hemineglect.

Spontaneous eye movements during imagery are not random and can be used to study and reveal mental visualization processes (Fourtassi et al., 2013; Johansson et al. 2006). For example, we previously showed that during memory recall of French towns via imagery healthy individuals looks straight ahead when recalling Paris and their subsequent gaze positions are significantly correlated with the real GPS coordinates of the recalled towns. This correlation suggests that memory retrieval is done via depictive representations as it is never found when the towns are recalled using verbal fluency. In the present paper we added to this finding by showing that the mental image is spontaneously centered on the head or body midline. In order to investigate the capacities of visual imagery in patients, and by extension, the role of primary visual cortex and fronto-parietal cortex in spatial visual imagery, we recorded gaze positions during memory recall of French towns in an imagery task, a non-imagery task (verbal fluency), and a visually-guided task in five patients with left or right hemianopia and in four patients with hemineglect (two with left hemianopia and two without). The correlation between gaze position and real GPS coordinates of the recalled towns was significant in all hemianopic patients, but in patients with hemineglect this was only the case for towns located on the right half of the map of France. This suggests hemianopic patients can perform spatially consistent mental imagery despite direct or indirect unilateral lesions of the primary visual cortex. In contrast, the left-sided towns recalled by hemineglect patients, revealed that they have some spatial inconsistency or representational difficulty. Hemianopic patients positioned and maintained their gaze in their contralesional hemispace, suggesting that their mental map was not centered on their head or body midline. This contralesional gaze positioning appeared to be a general compensation strategy and was not observed in patients with neglect (with or without hemianopia). Instead, neglect patients positioned their gaze in their ipsilesional hemispace and only when performing the visual imagery task. These findings are discussed in the context of the role of occipital and fronto-parietal cortices in the neuroanatomical model of visual imagery developed by Kosslyn et al. (2006).

Neuroplasticity of imagined wrist actions after spinal cord injury: a pilot study.

Motor imagery (MI - i.e., the mental representation of an action without physically executing it) stimulates brain motor networks and promotes motor learning after spinal cord injury (SCI). An interesting issue is whether the brain networks controlling MI are being reorganized with reference to spared motor functions. In this pilot study, we tested using magnetoencephalography (MEG) whether changes in cortical recruitment during MI were related to the motor changes elicited by rehabilitation. Over a 1-year period of inclusion, C6 SCI participants (n = 4) met stringent criteria for inclusion in a rehabilitation program focused on the tenodesis prehension (i.e., a compensatory prehension enabling seizing of objects in spite of hand and forearm muscles paralysis). After an extended baseline period of 5 weeks including repeated MEG and chronometric assessments of motor performance, MI training was embedded to the classical course of physiotherapy for five additional weeks. Posttest MEG and motor performance data were collected. A group of matched healthy control participants underwent a similar procedure. The MI intervention resulted in changes in the variability of the wrist extensions, i.e., a key movement of the tenodesis grasp (p < .05). Interestingly, the extent of cortical recruitment, quantified by the number of MEG activation sources recorded within Brodmann areas 1-8 during MI of the wrist extension, significantly predicted actual movement variability changes across sessions (p < .001). However, no such relationship was present for movement times. Repeated measurements afforded a reliable statistical power (range .70-.97). This pilot study does not provide straightforward evidence of MI efficacy, which would require a randomized controlled trial. Nonetheless, the data showed that the relationship between action and imagery of spared actions may be preserved after SCI.

Motor inhibition during motor imagery: a MEG study with a quadriplegic patient.

The neurophysiological substrates underlying motor imagery are now well established. However, the neural processes of motor inhibition while mentally rehearsing an action are poorly understood. This concern has received limited experimental investigations leading to divergent conclusions. Whether motor command suppression is mediated by specific brain structures or by intracortical facilitation/inhibition is a matter of debate. Interestingly, although motor commands are inhibited during motor imagery (MI) in healthy participants, spinal cord injury may result in weakened motor inhibition. Using magentoencephalography, we observed that mental and actual execution of a goal-directed pointing task elicited similar primary motor cortex activation in a C6-C7 quadriplegic patient, thus confirming the hypothesis of weakened motor inhibition during MI. In an age-matched healthy control participant, however, primary motor area activation during MI was significantly reduced compared to physical practice. Brain activation during actual movement resulted in enhanced recruitment of premotor areas in the patient. In the healthy participant, we found functional relationships between the primary motor area and peri-rolandic sites including the primary sensory area and the supplementary motor area during MI. This neural network was not activated when the quadriplegic patient performed MI. We assume that the primary sensory area and the supplementary motor area may be part of a functional network underlying motor inhibition during MI. These data provide insights into brain function changes due to neuroplasticity after spinal cord injury and evidence cortical substrates underlying weakened motor inhibition during MI after deafferentation and deefferentation.

Iterative fragmentation of cognitive maps in a visual imagery task.

It remains unclear whether spontaneous eye movements during visual imagery reflect the mental generation of a visual image (i.e. the arrangement of the component parts of a mental representation). To address this specificity, we recorded eye movements in an imagery task and in a phonological fluency (non-imagery) task, both consisting in naming French towns from long-term memory. Only in the condition of visual imagery the spontaneous eye positions reflected the geographic position of the towns evoked by the subjects. This demonstrates that eye positions closely reflect the mapping of mental images. Advanced analysis of gaze positions using the bi-dimensional regression model confirmed the spatial correlation of gaze and towns' locations in every single individual in the visual imagery task and in none of the individuals when no imagery accompanied memory retrieval. In addition, the evolution of the bi-dimensional regression's coefficient of determination revealed, in each individual, a process of generating several iterative series of a limited number of towns mapped with the same spatial distortion, despite different individual order of towns' evocation and different individual mappings. Such consistency across subjects revealed by gaze (the mind's eye) gives empirical support to theories postulating that visual imagery, like visual sampling, is an iterative fragmented processing.

Rehabilitation of the elbow extension with motor imagery in a patient with quadriplegia after tendon transfer.

OBJECTIVE: To test the effect of a postsurgical motor imagery program in the rehabilitation of a patient with quadriplegia. DESIGN: Crossover design with kinematic analysis. SETTING: Rehabilitation Hospital of Lyon. Study approved by the local Human Research Ethics Committee. PARTICIPANTS: C6-level injured patient (American Spinal Injury Association Impairment Scale grade A) with no voluntary elbow extension (triceps brachialis score 1). INTERVENTION: The surgical procedure was to transfer the distal insertion of the biceps brachii onto the triceps tendon of both arms. The postsurgical intervention on the left arm included 10 sessions of physical rehabilitation followed by 10 motor imagery sessions of 30 minutes each. The patient underwent 5 sessions a week during 2 consecutive weeks. The motor imagery content included mental representations based on elbow extension involved in goal-directed movements. The rehabilitation period of the right arm was reversed, with motor imagery performed first, followed by physical therapy. MAIN OUTCOME MEASURES: The kinematics of upper-limb movements was recorded (movement time and variability) before and after each type of rehabilitation period. A long-term retention test was performed 1 month later. RESULTS: Motor imagery training enhanced motor recovery by reducing hand trajectory variability-that is, improving smoothness. Motor performance then remained stable over 1 month. CONCLUSIONS: Motor imagery improved motor recovery when associated with physical therapy, with motor performance remaining stable over the 1-month period. We concluded that motor imagery should be successfully associated with classic rehabilitation procedure after tendon transfer. Physical sessions may thus be shortened if too stressful or painful.

Wheel-chair driving improvement following visuo-manual prism adaptation.

Prism adaptation has been used for several years to improve several aspects of unilateral neglect. Parameters ranging from the classical neuropsychological tests to mental imagery or to tactile extinction have been successfully ameliorated following a brief period of adaptation to wedge prisms shifting the visual field to the right. However the potential therapeutic implications of this technique depend on the investigation of more functional and ecological parameters. Here we describe a patient with left hemiplegia and unilateral neglect who was impaired during wheel-chair navigation in the clinical unit. Following a brief adaptation period, this patient showed a sudden improvement of wheel-chair driving as well as of classical tests. The potential implications of prism adaptation for the rehabilitation of unilateral neglect are highlighted by the long duration of improvement obtained after a single adaptation session.

Neglect and prism adaptation: a new therapeutic tool for spatial cognition disorders.

PURPOSE: A large proportion of right-hemisphere stroke patients show unilateral neglect, a neurological deficit of perception, attention, representation, and/or performing actions within their left-sided space, inducing many functional debilitating effects on everyday life, and responsible for poor functional recovery and ability to benefit from treatment. This spatial cognition disorder affects the orientation of behaviour with a shift of proprioceptive representations toward the lesion side. METHODS: This shift can be reduced after a prism adaptation period to a right lateral displacement of visual field (induced by a simple target-pointing task with base-left wedge prisms). The modification of visuo-motor or sensory-motor correspondences induced by prism adaptation involves improvement of different symptoms of neglect. RESULTS: Classical visuo-motor tests could be improved for at least 2h after adaptation, but also non-motor and non-visual tasks. In addition, cross-modal effects have been described (tactile extinction and dichotic listening), mental imagery tasks (geographic map, number bisection) and even visuo-constructive disorders. These cognitive effects are shown to result from indirect bottom-up effects of the deeper, adaptive realignment component of the reaction to prisms. Lesion studies and functional imaging data evoke a cerebello-cortical network in which each structure plays a specific role and not all structures are crucial for adaptation ability. CONCLUSIONS: These cognitive effects of prism adaptation suggest that prism adaptation does not act specifically on the ipsilesional bias characteristic of unilateral neglect but rehabilitates more generally the visuo-spatial functions attributed to the right cortical hemisphere. These results reinforce the idea that the process of prism adaptation may activate brain functions related to multisensory integration and higher spatial representations and show a generalization at a functional level. Prism adaptation therefore appears as a new powerful therapeutic tool for spatial cognition disorders.

Prism adaptation first among equals in alleviating left neglect: a review.

PURPOSE: The current paper was designed to provide a critical overview on the different methods proposed for the rehabilitation of left spatial neglect. METHODS: On the basis of a previous systematic review of the literature, we analyzed all articles available aiming at reducing left spatial neglect which included a long term functional assessment. RESULTS: The aim of most early rehabilitation approaches, such as visuo-scanning training, was to re-orient visual scanning toward the neglected side. This review confirmed the utility of this method for rehabilitation purposes. More recent - theory driven - procedures, also based on a training approach, include limb activation, mental imagery training and video-feedback training. Although there is ground for optimism, the functional effectiveness of these methods still relies on few single-case studies. Newer methods have tried to stimulate automatic orientation of gaze or attention towards neglected space in a bottom-up fashion. Sensory stimulations can remove most of the classical signs of left neglect but their effects are short-lived. Such stimulations are not functionally relevant for rehabilitation except for trunk rotation or repeated neck muscle vibrations if they are associated with an extensive training program. A more promising intervention is prism adaptation given the growing evidence of relatively long-term functional gains from comparatively short term usage. CONCLUSION: Overall, there is now evidence for several clinically relevant long-term benefits in the case of visual scanning training, mental imagery training, video feedback training, neck muscle vibration and trunk rotation if associated with visual scanning training and prism adaptation. However, the amount of evidence is still limited to a small number of relevant published articles and it is mandatory to continue the research in this field. In this review, the possible routes for new rehabilitation procedures are discussed on the basis of the actual knowledge regarding the neuro-cognitive mechanisms underlying the therapeutic effect of prism adaptation.

Visuo-spatial neglect: a systematic review of current interventions and their effectiveness.

Left visuo-spatial neglect is a well-recognized predictor of poor functional outcome following right hemisphere stroke. Over the past 60 years, 18 different methods have been described and evaluated aimed at reducing the effects of this impairment. Although there are some grounds for optimism particularly in terms of short-term impairment-based effects, the range and degree of disability borne by many patients remain high and the clinical effectiveness of the different methods viewed in terms of long-lasting functional improvement (i.e. improvement of disabilities or handicap) is not clear. A systematic review of the available clinically relevant literature, using comparative and stringent levels of evidence, indicates that visual scanning training (VST), trunk rotation (TR) or repeated neck muscle vibrations (NMV) when associated with an extensive training program, mental imagery training, video feedback training and prism adaptation (PA) can be recommended for the rehabilitation of patients with left neglect. More studies however are needed to determine the optimal paradigm of limb activation (LA) eliciting a sustained functional improvement. Sensory stimulations alone and Fresnel prisms do not appear to be functionally relevant. For the other methods, the actual literature is not sufficient to conclude whether or not a long-term functional improvement can be achieved.

Bottom-up transfer of sensory-motor plasticity to recovery of spatial cognition: visuomotor adaptation and spatial neglect.

A large proportion of right-hemisphere stroke patients show hemispatial neglect, a neurological deficit of perception, attention, representation, and/or performing actions within their left-sided space, inducing many functional debilitating effects on everyday life, and responsible for poor functional recovery and ability to benefit from treatment. This spatial cognition disorder affects the orientation of behavior with a shift of proprioceptive representations toward the lesion side. This shift is similar to that produced by psychophysical manipulations as a wedge-prism exposure in normal healthy subjects. In both subjects, one major compensative effect of short-term prism adaptation is a shift of proprioceptive representations, demonstrated by a shift in manual straight-ahead pointing in the dark, in a direction opposite to the visual shift. In neglect patients, prism adaptation involves the shift of proprioceptive representations to the left with a reduction of rightward bias observed in neglect patients in visuo-manual tasks as line-bisection, line-cancellation or copy drawing. Improvement of neglect is also observed in no visuo-manual tasks as mental imagery, auditory extinction or posture. This generalization of prism adaptation effects at different neglect level symptoms suggests that the process of prism adaptation may activate brain functions related to multisensory integration and higher spatial representations. Moreover the positive effects found for both sensorimotor and more cognitive spatial functions lasted for at least two or more hours after prism removal. Unlike reduction of neglect through sensory stimulations, the long-lasting improvement of neglect after prism adaptation suggests the activation of short-term plasticity of brain functions related to coordinate transformations and space representations. Lastly, the duration of these effects could be useful in rehabilitation programs, as suggested by the effects of prism adaptation on disabling neglect symptoms as wheelchair driving, posture or writing.

Bilateral vestibular stimulation does not improve visual hemineglect.

This work compared the effect of unilateral (right and left) and bilateral vestibular stimulation in a right-brain-damaged patient with neglect. Neglect was improved following left caloric vestibular stimulation, and worsened following right vestibular stimulation. On the other hand, no modification of neglect was observed after bilateral vestibular stimulation. These results support the idea that caloric vestibular stimulation may improve neglect through a specific effect; bilateral stimulation making the putative activation bilateral and symmetrical does not affect the lateral bias of neglect.

Improvement of mental imagery after prism exposure in neglect: a case study.

Previous work has shown that various symptoms of unilateral neglect, including the pathological shift of the subjective midline to the right, may be improved by a short adaptation period to a prismatic shift of the visual field to the right. We report here the improvement of imagined neglect after prism exposure in a patient with a left unilateral neglect. Despite a strong neglect observed for mental images as well as for conventional tests, the mental evocation of left-sided information from an internal image of the map of France map was fully recovered following prism adaptation to the right. This improvement could not be explained by the alteration of visuomotor responses induced by the prism adaptation. Prism adaptation may therefore act not only on sensory-motor levels but also on a higher cognitive level of mental space representation and/or exploration.