Belén Rubio Ballester

Social Integration of Stroke Patients through the Multiplayer Rehabilitation Gaming System

Stroke is a leading cause of serious long-term disability in adults (Go et al, 2013). The impact of stroke induced impairments goes beyond the mere loss of motor abilities. The psychosocial implications caused by changes in performance of the activities of daily living have to be considered in modern rehabilitation processes since they do influence the potential outcome. From the perspective of traditional rehabilitation it is difficult to directly address these social factors. Here we propose to capitalize on a rising trend in rehabilitation to deploy virtual reality environments in order to overcome this limitation. By creating a multiplayer game that enhances performance of the patient through an adaptive mapping methodology, we compensate for motor impairments and allow the patient to interact with other participants on an equal level. We propose that this approach influences psychosocial dynamics as it changes the participant’s mutual perception. We conducted a psychosocial study to gain insight into the patients’ social environment and tested the system in two at home experiments. The results suggest that our system is able to equalize a healthy and disabled player and benefits the social interaction.

The visual amplification of goal-oriented movements counteracts acquired non-use in hemiparetic stroke patients

BackgroundStroke-induced impairments result from both primary and secondary causes, i.e. damage to the brain and the acquired non-use of the impaired limbs. Indeed, stroke patients often under-utilize their paretic limb despite sufficient residual motor function. We hypothesize that acquired non-use can be overcome by reinforcement-based training strategies.MethodsHemiparetic stroke patients (n = 20, 11 males, 9 right-sided hemiparesis) were asked to reach targets appearing in either the real world or in a virtual environment. Sessions were divided into 3 phases: baseline, intervention and washout. During the intervention the movement of the virtual representation of the patients’ paretic limb was amplified towards the target.ResultsWe found that the probability of using the paretic limb during washout was significantly higher in comparison to baseline. Patients showed generalization of these results by displaying a more substantial workspace in real world task. These gains correlated with changes in effector selection patterns.ConclusionsThe amplification of the movement of the paretic limb in a virtual environment promotes the use of the paretic limb in stroke patients. Our findings indicate that reinforcement-based therapies may be an effective approach for counteracting learned non-use and may modulate motor performance in the real world.Stroke-induced impairments result from both primary and secondary causes, i.e. damage to the brain and the acquired non-use of the impaired limbs. Indeed, stroke patients often under-utilize their paretic limb despite sufficient residual motor function. We hypothesize that acquired non-use can be overcome by reinforcement-based training strategies. Hemiparetic stroke patients (n = 20, 11 males, 9 right-sided hemiparesis) were asked to reach targets appearing in either the real world or in a virtual environment. Sessions were divided into 3 phases: baseline, intervention and washout. During the intervention the movement of the virtual representation of the patients’ paretic limb was amplified towards the target. We found that the probability of using the paretic limb during washout was significantly higher in comparison to baseline. Patients showed generalization of these results by displaying a more substantial workspace in real world task. These gains correlated with changes in effector selection patterns. The amplification of the movement of the paretic limb in a virtual environment promotes the use of the paretic limb in stroke patients. Our findings indicate that reinforcement-based therapies may be an effective approach for counteracting learned non-use and may modulate motor performance in the real world.

Counteracting learned non-use in chronic stroke patients with reinforcement-induced movement therapy

BackgroundAfter stroke, patients who suffer from hemiparesis tend to suppress the use of the affected extremity, a condition called learned non-use. Consequently, the lack of training may lead to the progressive deterioration of motor function. Although Constraint-Induced Movement Therapies (CIMT) have shown to be effective in treating this condition, the method presents several limitations, and the high intensity of its protocols severely compromises its adherence. We propose a novel rehabilitation approach called Reinforcement-Induced Movement Therapy (RIMT), which proposes to restore motor function through maximizing arm use. This is achieved by exposing the patient to amplified goal-oriented movements in VR that match the intended actions of the patient. We hypothesize that through this method we can increase the patients self-efficacy, reverse learned non-use, and induce long-term motor improvements.MethodsWe conducted a randomized, double-blind, longitudinal clinical study with 18 chronic stroke patients. Patients performed 30 minutes of daily VR-based training during six weeks. During training, the experimental group experienced goal-oriented movement amplification in VR. The control group followed the same training protocol but without movement amplification. Evaluators blinded to group designation performed clinical measurements at the beginning, at the end of the training and at 12-weeks follow-up. We used the Fugl-Meyer Assessment for the upper extremities (UE-FM) (Sanford et al., Phys Ther 73:447–454, 1993) as a primary outcome measurement of motor recovery. Secondary outcome measurements included the Chedoke Arm and Hand Activity Inventory (CAHAI-7) (Barreca et al., Arch Phys Med Rehabil 6:1616–1622, 2005) for measuring functional motor gains in the performance of Activities of Daily Living (ADLs), the Barthel Index (BI) for the evaluation of the patient’s perceived independence (Collin et al., Int Disabil Stud 10:61–63, 1988), and the Hamilton scale (Knesevich et al., Br J Psychiatr J Mental Sci 131:49–52, 1977) for the identification of improvements in mood disorders that could be induced by the reinforcement-based intervention. In order to study and predict the effects of this intervention we implemented a computational model of recovery after stroke.ResultsWhile both groups showed significant motor gains at 6-weeks post-treatment, only the experimental group continued to exhibit further gains in UE-FM at 12-weeks follow-up (p<.05). This improvement was accompanied by a significant increase in arm-use during training in the experimental group.ConclusionsImplicitly reinforcing arm-use by augmenting visuomotor feedback as proposed by RIMT seems beneficial for inducing significant improvement in chronic stroke patients. By challenging the patients’ self-limiting believe system and perceived low self-efficacy this approach might counteract learned non-use.Trial registrationClinical Trials NCT02657070.

Reinforcement-induced movement therapy: A novel approach for overcoming learned non-use in chronic stroke patients

An open question in stroke rehabilitation is, if and how chronic patients can still make improvements after they reached a plateau in motor recovery. Previous research has shown that Constraint-Induced Movement Therapy (CIMT) might be effective in treating hemiparesis and supporting functional improvements in chronic patients, but that it might also be associated with higher costs in terms of demand, resources and inconvenience for the patient. Here, we offer a new therapeutic approach that combines CIMT with a positive reinforcement component. We suggest that this new therapy, called Reinforcement-Induced Movement Therapy (RIMT), might be similarly effective as CIMT and could be suitable for a broader population of chronic stroke patients. We first implemented a computational model to study the potential outcome of different CIMT and RIMT therapy combinations. Then we present the results of an ongoing clinical trial that supports predictions from the model. We conclude that an optimally combined CIMT and RIMT therapy might propose a novel and powerful rehabilitation approach, addressing the specific needs of chronic stroke patients.

Accelerating motor adaptation by virtual reality based modulation of error memories

When exposed to visual perturbations, the motor system rapidly learns to reduce errors through adaptation of future motor commands. However, in cerebellar and stroke patients with proprioceptive impairments, motor adaptation rates are significantly slower. A recent study suggests that adaptation rates may be modulated by the stability of perturbations and the history of errors. We hypothesize that reducing the visual magnitude of directional error in a reaching task should increase the speed of motor adaptation to a perturbation. We developed a method for the modulation of error magnitudes in virtual reality (VR), and we conducted two experiments exploring its effects on adaptation. 34 healthy subjects used a chair-mounted arm support to perform reaching movements towards a target while learning to compensate for visuomotor rotations. We observed that diminishing the visually perceived variability of visual directional error through VR accelerates adaptation. This effect showed persistence into trials when virtual error reduction was no longer present confirming the modulatory role of error memory. These findings support the hypothesis that the brain may keep a history of recent errors and differentially adjusts learning rates relative to the frequency of occurrence of errors. We predict that exposure to a distribution of visual motor errors with low variability and centered around task-relevant error values accelerates motor adaptation in patients with cerebellar degeneration.

The effect of social gaming in virtual reality based rehabilitation of stroke patients

Therapy for motor recovery in stroke patients is strongly related to motivation and social factors [1, 2]. In this study, we evaluate the effects of social interaction in stroke rehabilitation.

Self beyond the body: task-relevant distal cues modulate performance and body ownership

The understanding of Body Ownership (BO) largely relies on the Rubber Hand Illusion (RHI) where synchronous stroking of real and Rubber Hands (RH) leads to an illusion of ownership of RH provided physical, anatomical, postural and spatial plausibility of the two body-parts. RHI also occurs during visuomotor synchrony, in particular, when the visual feedback of virtual arm movements follows the trajectory of the instantiated motor command. Hence BO seems to result from a bottom-up integration of afferent and efferent proximal multisensory evidence, and top-down prediction of both externally and self-generated signals, which occurs when the predictions about upcoming sensory signals are accurate. In motor control, the differential processing of predicted and actual sensory consequences of self-generated actions is addressed by, the so-called, Forward Model (FM). Based on an efference copy or corollary discharge, FM issues predictions about the sensory consequences of motor commands and compares them with the actual outcome. The discrepancies (Sensory Prediction Errors, SPEs) are used to correct the action on the consecutive trial and provide new estimates of the current state of the body and the environment. Here, we propose that BO might be computed by FMs, and therefore, it might depend on their consistency, specifically, in contexts where the sensory feedback is self-generated. Crucially, to reduce SPE, FMs integrate both proximal (proprioceptive) and distal (vision, audition) sensory cues relevant to the task. Thus, if BO depends on the consistency of FMs, it would be compromised by the incongruency of not only proximal but also distal cues. To test our hypothesis, we devised an embodied VR-based task where action outcomes were signaled by distinct auditory cues. By manipulating the cues with respect to their spatiotemporal congruency and valence, we show that distal feedback which violates predictions about action outcomes compromises both BO and performance. These results demonstrate that BO is influenced by not only efferent and afferent cues which pertain to the body itself but also those arising outside of the body and suggest that in goal-oriented tasks BO might result from a computation of FM.

Depression Modulates Attentional Processing After Stroke

Depression is a common sequela after stroke and has severe implications on a patient’s life. Post-stroke depression has been linked to cognitive impairment, but the mechanisms that lead to this deficit are not well understood. We tested 18 chronic stroke patients with depression in a psychophysical task to evaluate their attentional processing under varying cognitive loads. We found that the level of depression had no effect on the unconscious, bottom-up components of attentional processing but did influence the top-down ones. These results support the notion that depression might act like an additional cognitive load, impeding the conscious processes and responses although the information has been unconsciously processed.

Author Correction: Visuotactile integration modulates motor performance in a perceptual decision-making task

A correction to this article has been published and is linked from the HTML version of this paper. The error has been fixed in the paper.a

Goal-oriented feedback on motor behavior in virtual reality based stroke therapy: A case study using the rehabilitation gaming system

Aims: We address the role of short-term goals in virtual reality (VR) applications for motor relearning, which benefit stroke therapy. Methods: We let stroke patients as well as healthy participants perform reaching tasks in a VR environment for motor rehabilitation, the so-called rehabilitation gaming system (RGS). During the task, patients were provided with feedback about one’s own performance (mastery goal), healthy participants additionally received feedback of others performances (ego goal). Measurements include protocols for motor learning and different kinetic variables (both stroke patients and healthy participants) as well as subscales of the intrinsic motivation inventory (IMI) (only healthy participants). As healthy participants showed lower fatigue levels, we could apply additional measurements. Results: Both mastery goals and ego goals potentially enhance intrinsic Sebastian Marwecki1, Belén Rubio Ballester1, Esther Duarte2, Paul F.M.J. Verschure1,3 Affiliations: 1Laboratory of Synthetic Perceptive, Emotive and Cognitive Systems, Center of Autonomous Systems and Neurorobotics, Pompeu Fabra, Roc Boronat, Barcelona, Spain; 2Servei de Medicina Física I Rehabilitació, Hospitals del Mar I l’Esperança, Institut Hospital del Mar d’Investigacions Mèdiques, Barcelona, Spain; 3ICREA, Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys, Barcelona, Spain. Corresponding Author: Paul Verschure, Plaça de la Mercè, 10, 08002 Barcelona; Email: paul.verschure@upf.edu Received: 10 October 2016 Accepted: 17 January 2017 Published: 23 March 2017 motivation and adherence, as they show to foster task performance (e.g., response time in mastery goals decreased with p = 0.014 for healthy participants, for stroke patients with p = 0.011 in the first iteration) as well as perceived effort (p = 0.007 for mastery, p = 0.008 for ego goals). As a secondary outcome, by controlling task difficulty, motor learning does not change across conditions (p = 0.316 for stroke patients, p = 0.323 for healthy participants). This raises the question whether or not task difficulty alone fosters the effectivity of VR based therapy applications, i.e., motor learning, to which motivators such as short-term goals provide little trade-off. Conclusion: Firstly, we suggest the implementation of mastery and ego goals in VR based stroke therapy, as adherence benefits from the motivational context they provide. Secondly, we argue towards simplicity regarding heuristics in therapeutic game design, which apparently often does not differ from conventional game design apart from setting the right level of challenge.