Robot-aided intensive training in post-stroke recovery

Exploring the relationship between visuospatial function and age-related deficits in motor skill transfer

BACKGROUND

Generalizing learned information from one motor task to another is critical for effective motor rehabilitation. A recent study demonstrated age-related declines in motor skill transfer, yet findings from other motor learning studies suggest that visuospatial impairments may explain such aging effects.

AIMS

The purpose of this secondary analysis was to test whether age-related deficits in motor skill transfer were related to low visuospatial ability.

METHODS

Forty-two participants (mean ± SD age: 72.1 ± 9.9 years) were tested on an upper extremity dexterity task before and after 3 days of training on an upper extremity reaching task. Training and control data have been published previously. Prior to training, global cognitive status and specific cognitive domains (visuospatial/executive, attention, and delayed memory) were evaluated using the Montreal Cognitive Assessment.

RESULTS

Backward-stepwise linear regression indicated that the Visuospatial/Executive subtest was related to motor skill transfer (i.e., the amount of change in performance on the untrained motor task), such that participants with higher visuospatial scores improved more on the untrained dexterity task than those with lower scores. Global cognitive status was unrelated to motor skill transfer.

DISCUSSION

Consistent with previous studies showing a positive relationship between visuospatial function and other aspects of motor learning, this secondary analysis indicates that less motor skill transfer among older adults may indeed be due to declines in visuospatial function.

CONCLUSIONS

The present study highlights the potential utility of assessing older patients' visuospatial ability within motor rehabilitation to provide valuable insight into the extent to which they may learn and generalize motor skills through training.

Wrist Rehabilitation Assisted by an Electromyography-Driven Neuromuscular Electrical Stimulation Robot After Stroke

BACKGROUND

Augmented physical training with assistance from robot and neuromuscular electrical stimulation (NMES) may introduce intensive motor improvement in chronic stroke.

OBJECTIVE

To compare the rehabilitation effectiveness achieved by NMES robot-assisted wrist training and that by robot-assisted training.

METHODS

This study was a single-blinded randomized controlled trial with a 3-month follow-up. Twenty-six hemiplegic subjects with chronic stroke were randomly assigned to receive 20-session wrist training with an electromyography (EMG)-driven NMES robot (NMES robot group, n = 11) and with an EMG-driven robot (robot group, n = 15), completed within 7 consecutive weeks. Clinical scores, Fugl-Meyer Assessment (FMA), Modified Ashworth Score (MAS), and Action Research Arm Test (ARAT) were used to evaluate the training effects before and after the training, as well as 3 months later. An EMG parameter, muscle co-contraction index, was also applied to investigate the session-by-session variation in muscular coordination patterns during the training.

RESULTS

The improvement in FMA (shoulder/elbow, wrist/hand) obtained in the NMES robot group was more significant than the robot group (P < .05). Significant improvement in ARAT was achieved in the NMES robot group (P < .05) but absent in the robot group. NMES robot-assisted training showed better performance in releasing muscle co-contraction than the robot-assisted across the training sessions (P < .05).

CONCLUSIONS

The NMES robot-assisted wrist training was more effective than the pure robot. The additional NMES application in the treatment could bring more improvements in the distal motor functions and faster rehabilitation progress.

The value of robotic systems in stroke rehabilitation

In this paper, we discuss robot-mediated neurorehabilitation as a significant emerging field in clinical medicine. Stroke rehabilitation is advancing toward more integrated processes, using robotics to facilitate this integration. Rehabilitation approaches have tremendous value in reducing long-term impairments in stroke patients during hospitalization and after discharge, of which robotic systems are a new modality that can provide more effective rehabilitation. The function of robotics in rehabilitative interventions has been examined extensively, generating positive yet not completely satisfactory clinical results. This article presents state-of-the-art robotic systems and their prospective function in poststroke rehabilitation of the upper and lower limbs.

Randomized trial of a robotic assistive device for the upper extremity during early inpatient stroke rehabilitation

BACKGROUND

A recent Cochrane Review showed that early robotic training of the upper limb in stroke survivors can be more effective than other interventions when improving activities of daily living involving the arm function is the aim of therapy.

OBJECTIVE

We tested for efficacy of the study a protocol which involved the use of the NeReBot therapy in partial substitution of standard upper limb rehabilitation in post-acute stroke patients.

METHODS

In this dose-matched, randomized controlled clinical trial, 34 hemiparetic participants with movement against gravity in shoulder, elbow, and wrist muscle groups were enrolled within 15 days of the onset of stroke. All participants received a total daily rehabilitation treatment for 120 minutes, 5 days per week for 5 weeks. The control group received standard therapy for the upper limb. The experimental group received standard therapy (65% of exercise time) associated with robotic training (35% of exercise time). Muscle tone (Modified Ashworth Scale), strength (Medical Research Council), and synergism (Fugl-Meyer motor scores) were measured at impairment level, whereas dexterity (Box and Block Test and Frenchay Arm Test) and activities of daily living (Functional Independence Measure) were measured at activity level. All assessments were performed at baseline, at the end of therapy (time T1), at 3 months (time T2), and at 7 months (time T3) after entry. All between-group analyses were tested using nonparametric test with Bonferroni's adjustments for multiple testing.

RESULTS

No significant between-group differences were found with respect to demographic characteristics, motor, dexterity, and ADLs at baseline, postintervention (T1) and at follow-up (T2 and T3).

CONCLUSIONS

The robot therapy by NeReBot did not lead to better outcomes compared with conventional inpatient rehabilitation.

Effect of task-related continuous auditory feedback during learning of tracking motion exercises

Background

This paper presents the results of a set of experiments in which we used continuous auditory feedback to augment motor training exercises. This feedback modality is mostly underexploited in current robotic rehabilitation systems, which usually implement only very basic auditory interfaces. Our hypothesis is that properly designed continuous auditory feedback could be used to represent temporal and spatial information that could in turn, improve performance and motor learning.

Methods

We implemented three different experiments on healthy subjects, who were asked to track a target on a screen by moving an input device (controller) with their hand. Different visual and auditory feedback modalities were envisaged. The first experiment investigated whether continuous task-related auditory feedback can help improve performance to a greater extent than error-related audio feedback, or visual feedback alone. In the second experiment we used sensory substitution to compare different types of auditory feedback with equivalent visual feedback, in order to find out whether mapping the same information on a different sensory channel (the visual channel) yielded comparable effects with those gained in the first experiment. The final experiment applied a continuously changing visuomotor transformation between the controller and the screen and mapped kinematic information, computed in either coordinate system (controller or video), to the audio channel, in order to investigate which information was more relevant to the user.

Results

Task-related audio feedback significantly improved performance with respect to visual feedback alone, whilst error-related feedback did not. Secondly, performance in audio tasks was significantly better with respect to the equivalent sensory-substituted visual tasks. Finally, with respect to visual feedback alone, video-task-related sound feedback decreased the tracking error during the learning of a novel visuomotor perturbation, whereas controller-task-related sound feedback did not. This result was particularly interesting, as the subjects relied more on auditory augmentation of the visualized target motion (which was altered with respect to arm motion by the visuomotor perturbation), rather than on sound feedback provided in the controller space, i.e., information directly related to the effective target motion of their arm.

Conclusions

Our results indicate that auditory augmentation of visual feedback can be beneficial during the execution of upper limb movement exercises. In particular, we found that continuous task-related information provided through sound, in addition to visual feedback can improve not only performance but also the learning of a novel visuomotor perturbation. However, error-related information provided through sound did not improve performance and negatively affected learning in the presence of the visuomotor perturbation.

Upper limb movements and cerebral plasticity in post-stroke rehabilitation

Rehabilitative interventions for the plegic/paretic upper limb of stroke survivors are more effective if they are early, intensive, and provide multisensory stimulation. Various rehabilitative approaches have been proposed to date, but little has been published on clinical efficacy. The mechanism underlying recovery of neurological injury after stroke is still incompletely understood, but more than one process is probably involved and cerebral plasticity undoubtedly plays a key role. The goal of this review was to identify which movements and type of therapeutic arm exercises may influence cerebral plasticity in plegic/paretic stroke survivors. Evidence suggests that plasticity is stimulated more by the arm's movement trajectory than by its final position in space. Rehabilitation should be based on simple, repetitive, unidirectional or, better still, complex and multidirectional movements in all spatial planes, such as circular or spiral movements. It should also incorporate a feedback system, since this seems to bring about earlier and better motor and functional outcomes.