Mary Ellen Stoykov

Evaluation of robotic training forces that either enhance or reduce error in chronic hemiparetic stroke survivors.

This investigation is one in a series of studies that address the possibility of stroke rehabilitation using robotic devices to facilitate “adaptive training.” Healthy subjects, after training in the presence of systematically applied forces, typically exhibit a predictable “after-effect.” A critical question is whether this adaptive characteristic is preserved following stroke so that it might be exploited for restoring function. Another important question is whether subjects benefit more from training forces that enhance their errors than from forces that reduce their errors. We exposed hemiparetic stroke survivors and healthy age-matched controls to a pattern of disturbing forces that have been found by previous studies to induce a dramatic adaptation in healthy individuals. Eighteen stroke survivors made 834 movements in the presence of a robot-generated force field that pushed their hands proportional to its speed and perpendicular to its direction of motion — either clockwise or counterclockwise. We found that subjects could adapt, as evidenced by significant after-effects. After-effects were not correlated with the clinical scores that we used for measuring motor impairment. Further examination revealed that significant improvements occurred only when the training forces magnified the original errors, and not when the training forces reduced the errors or were zero. Within this constrained experimental task we found that error-enhancing therapy (as opposed to guiding the limb closer to the correct path) to be more effective than therapy that assisted the subject.

Using Motor Imagery in the Rehabilitation of Hemiparesis

OBJECTIVE To examine the effectiveness of using motor imagery training in the rehabilitation of hemiparesis. DESIGN A before-after trial with clinical and behavioral analyses of single cases. SETTING Academic-affiliated rehabilitation hospital. PARTICIPANTS Two survivors of embolic middle cerebral artery stroke that resulted in chronic hemiparesis. INTERVENTION A motor imagery training program consisting of imagined wrist movements (extension, pronation-supination) and mental simulations of reaching and object manipulation making use of a mirror box apparatus. Twelve 1-hour experimental sessions were delivered, 3 times a week for 4 consecutive weeks. MAIN OUTCOME MEASURES Two clinical assessments, grip strength, 4 wrist functionality measurements, and 3 timed performance tests. All outcome measures were recorded before training began, at 3 times during the intervention month, with 2 additional long-term measurements. RESULTS Performance of the paretic limb improved after the imagery intervention, indicated by increases in assessment scores and functionality and decreases in movement times. The improvements over baseline performance remained stable over a 3-month period. CONCLUSIONS These results demonstrate the potential for using motor imagery as a cognitive strategy for functional recovery from hemiparesis. The intervention targets the cognitive level of action processing while its effects may be realized in overt behavioral performance.

A Pneumatic Glove and Immersive Virtual Reality Environment for Hand Rehabilitative Training After Stroke

While a number of devices have recently been developed to facilitate hand rehabilitation after stroke, most place some restrictions on movement of the digits or arm. Thus, a novel glove was developed which can provide independent extension assistance to each digit while still allowing full arm movement. This pneumatic glove, the PneuGlove, can be used for training grasp-and-release movements either with real objects or with virtual objects in a virtual reality environment. Two groups of stroke survivors, with seven subjects in each group, completed a six-week rehabilitation training protocol, consisting of three 1-h sessions held each week. One group wore the PneuGlove during training, performed both within a novel virtual reality environment and outside of it with physical objects, while the other group completed the same training without the device. Across subjects, significant improvements were observed in the Fugl-Meyer Assessment for the upper extremity ( p<;;0.001), the hand/wrist portion of the Fugl-Meyer Assessment ( p<;;0.001), the Box and Blocks test ( p<;;0.05), and palmar pinch strength ( p<;;0.05). While changes in the two groups were not statistically different, the group using the PneuGlove did show greater mean improvement on each of these measures, such as gains of 3.7 versus 2.4 points on the hand/wrist portion of the Fugl-Meyer Assessment and 14 N versus 5 N in palmar pinch.

Comparison of Bilateral and Unilateral Training for Upper Extremity Hemiparesis in Stroke

Background. Upper extremity hemiparesis is the most common poststroke disability. Longitudinal studies have indicated that 30% to 66% of stroke survivors do not have full arm function 6 months poststroke. One promising treatment approach is bilateral training. To date, no randomized, blinded study of efficacy comparing 2 groups (bilateral training vs unilateral training) using analogous tasks has been performed in chronic stroke survivors with moderate upper extremity impairment. Objective. To compare the effectiveness of bilateral training with unilateral training for individuals with moderate upper limb hemiparesis. The authors hypothesized that bilateral training would be superior to unilateral training in the proximal extremity but not the distal one. Methods. Twenty-four subjects participated in a randomized, single-blind training study. Subjects in the bilateral group (n = 12) practiced bilateral symmetrical activities, whereas the unilateral group (n = 12) performed the same activity with the affected arm only. The activities consisted of reaching-based tasks that were both rhythmic and discrete. The Motor Assessment Scale (MAS), Motor Status Scale (MSS), and muscle strength were used as outcome measures. Assessments were administered at baseline and posttraining by a rater blinded to group assignment. Results. Both groups had significant improvements on the MSS and measures of strength. The bilateral group had significantly greater improvement on the Upper Arm Function scale (a subscale of the MAS-Upper Limb Items). Conclusion. Both bilateral and unilateral training are efficacious for moderately impaired chronic stroke survivors. Bilateral training may be more advantageous for proximal arm function.

Simulation of Bilateral Movement Training Through Mirror Reflection: A Case Report Demonstrating an Occupational Therapy Technique for Hemiparesis

Abstract In rehabilitation for hemiparesis, one of the goals of an occupational therapist is to practice upper extremity tasks with the recovering individual. The practice is intended to strengthen muscles and refine movements. It also provides examples for the recovering body and brain as they attempt to reestablish the now delicate cognitive and neural connections mediating voluntary behavior. However, the paresis significantly limits the movement sequence possibilities that may be physically practiced. We outline a method for using simulation of movement, which is intended to provide a means for experiencing a range of smooth and controlled movements completed by a paretic limb. The simulation provides a compelling perceptual experience of bilateral motion beyond the current capabilities of the affected limb. The benefits of this technique after a 3-week course of the simulation practice are exemplified by the presented case study that reveals improved function as demonstrated by increases in Fugl-Meyer scores and faster movement speeds as demonstrated by decreased movement times for the Jebsen test of hand function.

A review of bilateral training for upper extremity hemiparesis

Upper extremity hemiparesis is the most common post-stroke disability. Longitudinal studies have indicated that 30-66% of stroke survivors do not have full arm function 6 months post-stroke. The current gold standard for treatment of mild post-stroke upper limb impairment is constraint-induced therapy but, because of the inclusion criteria, alternative treatments are needed which target more impaired subjects. Bilateral arm training has been investigated as a potential rehabilitation intervention. Bilateral arm training encompasses a number of methods including: (1) bilateral isokinematic training; (2) mirror therapy using bilateral training; (3) device-driven bilateral training; and (4) bilateral motor priming. Neural mechanisms mediating bilateral training are first reviewed. The key bilateral training studies that have demonstrated evidence of efficacy will then be discussed. Finally, conclusions are drawn concerning clinical implications based on the reviewed literature.

Cortical Stimulation for Upper Limb Recovery Following Ischemic Stroke: A Small Phase II Pilot Study of a Fully Implanted Stimulator

Abstract Objective: To evaluate the feasibility of a fully implanted cortical stimulator for improving hand and arm function in patients following ischemic stroke. Method: Twenty-four chronic stroke patients with hemiplegia were randomized to targeted implanted cortical electrical stimulation of the motor cortex with upper limb rehabilitation therapy or rehabilitation therapy alone. Results: Using repeated measures regression models, we estimated and compared treatment effects between groups over the study follow-up period. The investigational group had significantly greater mean improvements in Upper Extremity Fugl-Meyer (UEFM) scores during the 6-month follow-up period (weeks 1–24 following therapy), as compared to the control group (difference in estimated means = 3.8, p = .042). Box and Block (B & B) test improvement from baseline scores were also significantly better in the investigational group across the 6-month follow-up assessments (difference in estimated means = 3.8, p = .046). There was one report of seizure after device implant but prior to cortical stimulation and rehabilitation therapy, but no reports of neurologic decline. There were no improvements seen in the other measures assessed. Conclusion: Evidence suggests that cortical stimulation with rehabilitation therapy produces a lasting treatment effect in upper extremity motor control and is not associated with serious neurological complications. A larger multicenter study is underway.

Motor priming in neurorehabilitation.

Priming is a type of implicit learning wherein a stimulus prompts a change in behavior. Priming has been long studied in the field of psychology. More recently, rehabilitation researchers have studied motor priming as a possible way to facilitate motor learning. For example, priming of the motor cortex is associated with changes in neuroplasticity that are associated with improvements in motor performance. Of the numerous motor priming paradigms under investigation, only a few are practical for the current clinical environment, and the optimal priming modalities for specific clinical presentations are not known. Accordingly, developing an understanding of the various types of motor priming paradigms and their underlying neural mechanisms is an important step for therapists in neurorehabilitation. Most importantly, an understanding of the methods and their underlying mechanisms is essential for optimizing rehabilitation outcomes. The future of neurorehabilitation is likely to include these priming methods, which are delivered prior to or in conjunction with primary neurorehabilitation therapies. In this Special Interest article, we discuss those priming paradigms that are supported by the greatest amount of evidence, including (i) stimulation-based priming, (ii) motor imagery and action observation, (iii) sensory priming, (iv) movement-based priming, and (v) pharmacological priming. Video Abstract available. (see Supplemental Digital Content 1, http://links.lww.com/JNPT/A86) for more insights from the authors.

Use of a pneumatic glove for hand rehabilitation following stroke

Hand impairment is common following stroke and is often resistant to traditional therapy methods. Successful interventions have stressed the importance of repeated practice to facilitate rehabilitation. Thus, we have developed a servo-controlled glove to assist extension of individual digits to promote practice of grasp-and-release movements with the hand. This glove, the PneuGlove, permits free movement of the arm throughout its workspace. A novel immersive virtual reality environment was created for training movement in conjunction with the device. Seven stroke suvrvivors with chronic hand impairment participated in 18 training sessions with the PneuGlove over 6 weeks. Overall, subjects displayed a significant 6-point improvement in the upper extremity score on the Fugl-Meyer assessment and this increase was maintained at the evaluation held one month after conclusion of all training (p < 0.01). The majority of this gain came from an increase in the hand/wrist score (3.8-point increase, p < 0.01). Thus, the system shows promise for rehabilitative training of hand movements after stroke.

Active-Passive Bilateral Therapy as a Priming Mechanism for Individuals in the Subacute Phase of Post-Stroke Recovery: A Feasibility Study

Stoykov ME, Stinear JW: Active-passive bilateral therapy as a priming mechanism for individuals in the subacute phase of post-stroke recovery: A feasibility study. Objective: To assess the feasibility of treating inpatient stroke survivors with active-passive bilateral therapy as a motor priming technique before occupational therapy. Design: Single case series with two matched pairs in the subacute post-stroke rehabilitation phase. The test patients received active-passive bilateral therapy plus upper limb motor training. Control patients received only the motor training. Results: Both Fugl-Meyer Upper Extremity scores and Action Research Arm Test scores improved in this small group of test and control patients. The magnitude of improvement was greater in test patients who received active-passive bilateral therapy plus unilateral training. Conclusions: We conclude that it is feasible and safe to administer active-passive bilateral therapy in a hospital setting.