Topics in Stroke Rehabilitation ISSN: 1074-9357 (Print) 1945-5119 (Online) Journal homepage: http://www.tandfonline.com/loi/ytsr20 Simulation of Bilateral Movement Training Through Mirror Reflection: A Case Report Demonstrating an Occupational Therapy Technique for Hemiparesis Jennifer A. Stevens & Mary Ellen Phillips Stoykov To cite this article: Jennifer A. Stevens & Mary Ellen Phillips Stoykov (2004) Simulation of Bilateral Movement Training Through Mirror Reflection: A Case Report Demonstrating an Occupational Therapy Technique for Hemiparesis, Topics in Stroke Rehabilitation, 11:1, 59-66 To link to this article: http://dx.doi.org/10.1310/GCFE-QA7A-2D24-KHRU Published online: 02 Feb 2015. Submit your article to this journal Article views: 4 View related articles Citing articles: 19 View citing articles Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ytsr20 Download by: [Orta Dogu Teknik Universitesi] Date: 09 February 2016, At: 12:04 Grand Rounds Elliot J. Roth, MD, Editor Downloaded by [Orta Dogu Teknik Universitesi] at 12:04 09 February 2016 Simulation of Bilateral Movement Training Through Mirror Reflection: A Case Report Demonstrating an Occupational Therapy Technique for Hemiparesis Jennifer A. Stevens and Mary Ellen Phillips Stoykov 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. Key words: bilateral, hemiparesis, simulation F or the hemiparetic stroke survivor, voluntary motor tasks that had once been relatively easy to accomplish become challenging: brushing teeth, reaching for a cup, shaking hands with a friend. The neural circuits in the brain that are responsible for mediating an action intention and an executed action that precisely reflects that intention are no longer intact. Traditional occupational therapy techniques address this incompatibility by using behavior repetition. However, muscle weakness, spasticity, and disruption in movement coordination associated with hemiparesis often make it difficult to achieve smooth and controlled behaviors, even in the case of therapistassisted movements. Moreover, the experience of the recovering individual is often compromised by perceptions of the self operating in an uncoordinated manner, which provides a limited degree of positive reinforcement. We describe a method that provides an individual with hemiparesis with a means to experience his or her impaired limb completing successful movements through the use of a movement simulation. In this method, the individual moves his or her unaffected limb around in space and, through reflection in a mirror, experiences the impaired limb moving in concert with the affected limb. The perception of the controlled movements is intended to trigger the cognitive and neural processes associated with successful voluntary action by the impaired limb that is unlikely to occur during behavior due to physical movement limitations. Mental simulation of movement, or motor planning, implicitly precedes but ultimately predicts the outcome of subsequent behavior.1 Thus, it offers a novel but suitable level of action processing to explicitly target during stroke rehabilitation. Theoretical motivation for the use of movement simulation as a technique to be used in a rehabiliJennifer A. Stevens, PhD, is Research Scientist, Sensory Motor Performance Program, Rehabilitation Institute of Chicago, and is Assistant Research Professor, Physical Medicine & Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, Illinois. Mary Ellen Phillips Stoykov, MS, OTR/L, is Research Therapist, Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Illinois. Top Stroke Rehabil 2004;11(1):59–66 © 2004 Thomas Land Publishers, Inc. www.thomasland.com 59 60 TOPICS IN STROKE REHABILITATION/WINTER 2004 Downloaded by [Orta Dogu Teknik Universitesi] at 12:04 09 February 2016 tation setting is motivated by two literatures: the corpus of studies demonstrating a tight link between mentally simulated and physically executed action, and the demonstrable benefits of bilateral movement training on functional recovery of a paretic limb. A pilot study was completed to demonstrate that individuals with hemiparesis are able to imagine their impaired limb completing imagined movements.2 Shared Characteristics Between Mental Simulation and Physical Performance of Actions There are several groups of studies that demonstrate a tight link between real and imagined actions. Chronometric studies have demonstrated similar movement time functions—those that conform to principles of human movement—in both modalities. For example, individuals require about the same amount of time to complete actual and imagined handwriting in both small and large sizes.3 The large-sized tracings cover more distance but the small tracings require an increased level of precision to maintain the same degree of accuracy; increases in movement times occur in both cases but for different reasons. Brain imaging investigations reveal that real and simulated actions activate overlapping neural networks. For example, both have been found to activate supplementary motor area (SMA), premotor cortex (PM), and the cerebellum.4,5 It has also been suggested that the prefrontal cortex is responsible for the creation and maintenance of explicit representations that guide thought and action.6 In addition to neural activation, mental and physical actions share another physiological mechanism, autonomic response. Autonomic responses, such as heart and respiratory rate, are found to increase during imagined movements, and the increases are proportional to the work load imagined.7 One practical advantage of the link between mental simulation of action and physical performance is that practice in one modality (mental simulation) enhances performance in the other (physical performance). It has been reported for some time that mental simulation of movement enhances subsequent physical performance.8 Why does this bene- ficial relationship occur? Because of the tight link between the neural encoding of represented and executed action and the downstream responses activated by mental rehearsal, it seems likely that the facilitation is an effect of priming. During mental rehearsal, the motor pathways needed for upcoming action are activated. During subsequent physical execution they may be recruited more quickly, which results in a faster response time and more accurate performance. Indeed, mental practice results in increased muscle strength; although during simulation of movement, surface EMG reveals no significant muscle activity.9 Benefits of Bilateral Movement Training on Functional Recovery of a Paretic Limb In the technique described here, the reflection of the unaffected limb results in the perception of the impaired limb moving around successfully in space. In some instances, gaze direction and attention may be placed only on the limb reflected in the mirror; however, in most cases the overall perception is of bilateral movement. Bilateral movement presents a simpler context for movement for the recovering individual. When both arms are moving together, the propensity toward limb synchronization is strengthened, which minimizes attentional demands.10 In this way, bilateral movement presents a greater possibility for the translation of a simpler motor output command than that associated with individual arm sequences.11 Bilateral arm training, compared to unilateral or other forms of motor training, reveals significant improvements in upper extremity movement in individuals with both chronic and acute hemiparesis,12–14 but the effects of bilateral training are less effective with individuals who have dense hemiplegia.15 Increases in function after bilateral movement programs suggest that an interhemispheric disinhibition occurs, which allows reorganization at the neural level.16 The disinhibition can result in the recruitment of undamaged neurons to construct new task-relevant neural networks. On this view, intact ipsilateral pathways in the damaged hemisphere along with corticospinal pathways and contralateral pathways from the undamaged hemi- Downloaded by [Orta Dogu Teknik Universitesi] at 12:04 09 February 2016 Bilateral Training Simulation sphere form a coalition of connections that may support motor output of the affected limb. Functional magnetic resonance imaging (fMRI) has been used to provide a very direct measure of the effects of bilateral and unilateral movements during recovery from hemiparesis.17 In the acute phase of recovery, bilateral movements enhance activation in the primary motor cortex of the affected hemisphere. As recovery progresses, this activation looks similar across unilateral and bilateral movement conditions. This result suggests that bilateral movements may result in enhanced performance of a paretic limb due to reorganization at the central command level in the acute phase of recovery. Beneficial effects of repetitive bilateral movements for individuals with chronic hemiparesis reported in some studies may be due to changes at a more peripheral level such as increase in muscle strength and/or loosening. Also, a late-phase “unmasking” effect remains a possibility. In the present study, we hypothesized that through repeated priming and activation of the motor-specific brain regions with mental simulation of movement via mirror reflection, functional recovery of real movement capability by a paretic limb may be enhanced. Namely, we anticipated improved upper extremity performance including flexion and extension synergies, active movements, stability and coordination of the wrist and hand as measured in the Fugl-Meyer, and increases in movement control as demonstrated by decreases in movement times for the Jebsen test of hand function. Movement assessments were completed before during and after the 3-week intervention to evaluate performance improvements. Our anticipated result is based on the positive effects found by bilateral training in previous studies with individuals with chronic hemiparesis and studies that demonstrated beneficial effects of movement simulation practice on subsequent behavioral performance. Method Participant The patient is a 63-year-old male who suffered right hemisphere, posterior internal capsule stroke 61 that resulted in chronic left-side paresis. In the acute stage of recovery, he had a left visual field cut that was mostly resolved by the time he participated in the present intervention. Time between date of stroke and study participation was 1 year and 3 months. At initial evaluation, the participant’s left upper extremity was evaluated. Although he had finger movement, he reported that he rarely used his hand. It was noted that his affected left hand moved slowly and with poor efficiency. Objective testing using the Jebsen Hand Test of Function18 indicated that the participant’s scores for the affected arm were between 6 and 10 standard deviations from the norm. Also, the participant had limited motion in his shoulder, forearm, and wrist. His total score for the upper extremity portion of the Fugl-Meyer Motor Function Test19 was 47 out of a possible 66. Materials and apparatus The mirror-box apparatus is made of an 18 x 24-in. mirror affixed to two wooden posts so the mirror can stand alone at the patient’s midline (Figure 1). Design and procedure The participant completed a 3-week course of mental simulation intervention, comprised of 1hour visits to the laboratory three times a week. For the first 20 minutes of each intervention session, he completed computer-generated exercises designed to provide practice for performance of mental representation tasks. The computer presented movies of a person completing a left hand wrist extension and pronation-to-supinations at various speeds. At the end of each movie, the participant was asked to imagine completing a movement just like the one he had just observed in the movie. After the motor imagery warm-up tasks, the participant completed 35 minutes of mirror box training. The structure of the mirror reflection tasks presented to the client can be tailored to individual needs. During the first week of the presented participant’s intervention, we focused the individual on learning to identify the hand reflected in the mirror as his own paretic limb moving around for him. The clinician and participant Downloaded by [Orta Dogu Teknik Universitesi] at 12:04 09 February 2016 62 TOPICS IN STROKE REHABILITATION/WINTER 2004 Figure 1. The model demonstrates use of the mirror box apparatus for an individual with left-side upper extremity paresis. The affected limb is actually at rest behind the mirror while the unaffected limb moves around in space creating a perception of bilateral movements including smooth movement completed by the simulation of the affected limb. worked on achieving this identification by completing simple movements like finger tapping or wrist flexion and extension. In the subsequent weeks, relatively simple tasks were completed. For example, the participant completed simple manipulation tasks with objects of various sizes and weights, including pouring liquid and drinking from a cup. Perceptually challenging tasks that rely on the reflection of the limb and objects in the mirror provide compelling simulation experience for the individual. For example, the placement of numbered objects in a distinct order such as object “1” next to the object numbered “4.” With numbers printed backwards on the objects, perception of the hand and objects reflected in the mirror (i.e., perception of the affected limb interacting with objects) is necessary to successfully complete the task. Highest complexity tasks involve the use of a stylus. The individual is given a pen or pencil and is asked to draw a circle or square, or even to draw a simple animal such as mouse (depending on ability and experience).* Ultimately, mirror therapy is intended to facilitate movement through the practice of bilateral, symmetrical activities even though during the intervention the impaired upper extremity is actually hidden behind the mirror. However, through use of the mirror, the client views a more successful action than if he or she were looking at the impaired extremity attempting to complete the same or similar tasks. It is noteworthy that the participant reported the mirror box to be a compelling and exciting task. *For right-hand–dominant individuals recovering from left-hemisphere stroke, handwriting may also be practiced with the left hand essentially writing backward to gain a feeling that the right (paretic) hand is handwriting rather smoothly. Bilateral Training Simulation Downloaded by [Orta Dogu Teknik Universitesi] at 12:04 09 February 2016 Assessments and analysis We used two standardized clinical evaluation tests as a means to quantify improvements in performance. The first, the Jebsen Hand Test of Function,18 is a timed movement test that includes six subtests, three of which were used: subtest 2, turning over 5 playing cards; subtest 6, moving empty cans from a table surface onto a low shelf; and subtest 7, moving weighted cans from a table surface onto a low shelf. Both limbs completed each task. The second test we used was the FuglMeyer Motor Function Test.19 We restricted our use of the test to the upper extremity portion, which assesses a variety of multijoint movement and grasp patterns of the upper limb. There are four subscales including (a) upper extremity (measure of proximal movement), (b) wrist, (c) hand, and (d) coordination/speed. The maximum possible score for these four categories combined is 66. The Fugl-Meyer was only administered to the paretic limb. Repeated-measures analysis of variance (ANOVA) for the Jebsen card turning, unweighted objects, and weighted objects timed movement tests with day of assessment entered as a linear covariate can reveal significant decreases in movement times. Results The objective of mirror box training is to improve the patient’s ability to perform meaningful tasks with the affected upper extremity. Use of the mirror apparatus enables participants to practice graded occupations in a simulated bilateral movement framework. Activities may be selected according to the abilities and interests of the individual. 63 In our study, the individual completed only 3 weeks of the simulation therapy, however gains were made as his participation in the intervention increased. There was a 4-point increase in the Fugl-Meyer score, and the Jebsen revealed an overall shift in movement times for the affected limb (see Table 1). Although the left limb continued to move at an overall slower pace than the unaffected limb, there was a significant limb-specific decrease in movement times. A repeatedmeasures ANOVA was completed separately for the card turning, unweighted objects, and weighted objects timed movement tests with day of assessment entered as a linear covariate revealing the following results: card turning, F(1, 2) = 252.122, p = .004; unweighted objects, F(1, 2) = 47.342, p = .020; and weighted objects, F(1, 2) = 120.143, p = .008. These results are depicted in Figure 2. Also, a significant interaction was obtained for the card turning, F(1, 2) = 36.806, p = .026, and unweighted object, F(91, 2) = 9.389, p = .092, tests between day of assessment and arm indicating that the affected limb improvements were significantly greater than gains made with the unaffected limb. Discussion One of the most intriguing results is the incremental decrease in movement times over the 3 weeks. Similarly, while the overall gains in the Fugl-Meyer were not large, the increases continued through the 3-week period, which suggests that the performance improvements that result from bilateral movement simulation are a timebased function. Mirror reflection has been used to examine Table 1. Assessments scores over the intervention period Test Fugl-Meyer score (max. 66) Baseline 47 Day 7 45 Day 14 48 Day 21 51 Jebsen (seconds) Unweighted objects Right limb Left limb 5.97 11.2 5.60 8.88 6.05 9.88 6.21 9.84 Weighted objects Right limb Left limb 6.02 10.02 5.99 10.24 6.50 9.50 7.09 9.34 Card turning Right limb Left limb 8.87 19.41 8.72 18.5 6.53 12.68 5.70 9.92 64 TOPICS IN STROKE REHABILITATION/WINTER 2004 (A) Card Turning 22 Limb 20 Left hand 18 Right hand 16 14 12 10 8 6 4 2 0 .00 7.00 14.00 21.00 Day Movement time(s) (B) Unweighted Objects 14 Limb 13 Left 12 Right 11 10 9 8 7 6 5 4 .00 7.00 14.00 21.00 Day (C) Weighted Objects 12 Limb Movement time(s) Downloaded by [Orta Dogu Teknik Universitesi] at 12:04 09 February 2016 Movement time(s) 24 Left Right 10 8 6 4 .00 7.00 14.00 21.00 Day Figure 2. Movement times decrease in each of the three timed movement tests: (A) card turning, (B) unweighted objects, and (C) weighted objects. Downloaded by [Orta Dogu Teknik Universitesi] at 12:04 09 February 2016 Bilateral Training Simulation phantom kinesthetics and, in some cases, treat phantom limb pain.20 One earlier report demonstrated improvements in paretic limb performance as well as improvements in perception from use of a mirror apparatus, however the gains in performance were measured using nonstandardized assessment techniques.21 Another report demonstrated performance improvement by a paretic limb after mirror reflection training, however the intervention was coupled with a constraintinduced protocol.22 The sending of successful action signals, even through simulation, may provide a critical step in the recovery process. Movement representation tasks invite an individual to think about the self in action. Previous investigations reveal that stroke survivors’ cognitive processing of action is not limited to the extent that physical behavior is.2 Therefore, cognitive motor tasks seem to provide a means for stroke survivors to “practice” movements despite physical disability. Indeed, because the intervention is based on mental, not physical, practice, it may be an appropriate therapeutic intervention to introduce in the acute or subacute stages of recovery when repetition of actual behaviors is the most compromised because of the movement impairment. 65 Optimally, mirror therapy, an innovative therapeutic method, may be used to augment standard occupational therapy neuromuscular techniques that focus specifically on physical practice of the affected limb. The case study nature of the present report is one limitation of our investigation. However, the report outlines a simple and compelling technique that may be easily adapted for the occupational therapist’s clinical setting. Future investigations will benefit from increased participant numbers, study of the optimal length of intervention of this kind, and measurement of long-term effects that result from a therapy that includes simulation of motor movements. Moreover, there needs to be further investigation of the clinical as well as statistical relevance of this intervention. The most effective interventions are those that not only significantly increase function and range of motion but also increase the individual’s ability to complete activities of daily living. Acknowledgments This research was supported by National Institutes of Health grant 1F32HD08648 and the Falk Trust. REFERENCES 1. Jeannerod M. The representing brain: neural correlates of motor intention and imagery. Behav Brain Sci. 1994;17:187–245. 2. Stevens JA, Phillips ME. Maintenance of implicit motor imagery in hemiplegia. 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