Influence of Posturographic Platform Biofeedback Training on the Dynamic Balance of Adult Stroke Patients Janusz Maciaszek, PhD,* Sylwia Borawska, MSc,† and Jacek Wojcikiewicz, MD†
The aim of the experiment was to analyze the influence of posturographic platform biofeedback training on the dynamic balance of patients who experienced ischemic stroke. The study included 21 patients treated at the Rehabilitation Center of the District Hospital in Bia1ogard, in the Ward of Neurological Rehabilitation with the Stroke Division. The age of the patients (11 in the experimental and 10 in the control group) ranged between 55 and 65 years. The level of dynamic balance was determined with Timed Up and Go Test. The experimental group was subjected to the biofeedback training, practicing maintenance of body balance (forced sway training) on posturographic platform for 15 consecutive days. The perception of dynamic balance in the group subjected to biofeedback training improved to a markedly greater extent (P , .05) as compared with conventionally rehabilitated group. Participation in biofeedback training exerted stronger effect on the dynamic balance of patients who experienced the stroke of the left hemisphere with right-sided hemiparesis than in those with right hemisphere stroke and left-sided hemiparesis. The utilization of feedback mechanisms during training on a posturographic platform can be reflected by enhanced stimulation and further improvement of the control of performed motor tasks. Key Words: Stroke—biofeedback—body balance—adults— posturography. Ó 2014 by National Stroke Association
Introduction Stroke constitutes an important cause of decreased functional capacity in humans.1 Among numerous consequences of the stroke, marked decrease in the perception of body balance and ability to maintain correct spatial orientation are frequently mentioned. These balance disorders can be reflected by an increased risk of falling, which is particularly high in neurologic patients.2-4 Not only are such disorders very frequent but can also persist for a considerable time after the stroke episode.5 From the *Department of Theory of Physical Education and Anthropomotorics, University School of Physical Education in Pozna n, Pozna n; and †Neurological Rehabilitation Unit, Rehabilitation Center of the Hospital in Bia1ogard, Poland. Received July 9, 2013; revision received September 4, 2013; accepted October 14, 2013. Address correspondence to Janusz Maciaszek, PhD, Department of Theory of Physical Education and Anthropomotorics, University School of Physical Education in Pozna n, ul. Kr olowej Jadwigi 27/39, 61–871 Pozna n, Poland. E-mail: [email protected]. 1052-3057/$ - see front matter Ó 2014 by National Stroke Association http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2013.10.029
Noticeably, the balance disorders markedly affect the patient’s daily living activities. Despite preventive measures, falls are significantly more frequent in stroke patients than in healthy individuals.6 Nyberg and Gustafson7 analyzed the risk of falling among 161 patients subjected to geriatric rehabilitation after the stroke and revealed that 39% of the subjects experienced falling. Of note is the high variability of factors that play a direct role in falling of such patients. According to Tsur and Segal,8 most documented falls affect patients who suffer from decreased muscular tone (70%), paresis (54%), or unilateral hypoesthesia. Other factors that increase the risk of falling in stroke patients include sedatives or neuroleptics, hemianopia, loss of vision, and visual agnosia. Campbell and Matthews9 published a comprehensive review of experiments addressing the potential risk factors of falling during hospital rehabilitation of men and women after stroke. The authors concluded that the specific risk of falling, such as balance disorders, visuospatial hemineglect, and lack of caution, can be stronger predictors of falling than more general risk factors such as age or impaired sensual function.
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Falls are particularly frequent among individuals with severe neurologic deficits, marked impairment, and neglect syndrome.10 However, the number of falls can be significantly reduced by properly conducted rehabilitation process; moreover, its effects can be observed quite quickly. Rogind et al11 revealed that early implemented rehabilitation activity is reflected by improvement of posturographic parameters during each (1st, 2nd, 4th, and between the 8th and 52nd) week of exercise. The rate and degree of patient’s improvement are modulated by an array of factors, such as the site and size of stroke, patient’s age, general status, and implemented therapeutic and rehabilitation modalities. Yelnik et al12 verified the role of this latter factor, comparing 2 rehabilitation strategies of improving balancing abilities of stroke patients. Their study included 28 patients who experienced the first episode of hemiparesis 3 to 15 months earlier. However, they did not confirm the superiority of multisensorial rehabilitation, as based on higher intensity of balance tasks and exercise during visual deprivation, over the neurodevelopmental theory–based therapy among patients treated at an outpatient setting. Biofeedback methods are used in rehabilitation with increasing frequency.13,14 Biofeedback enables obtaining information on the present state of the body with an aid of various devices. Such information enables voluntary changes to the spatial orientation of the body. The most frequently used types of feedback include visual, acoustic, thermal, strength, electromyographic, and electrokinesiologic biofeedback. Intiso et al15 emphasized the efficacy of this method during the rehabilitation of stroke patients. Nonetheless, each hemiparetic stroke patient may have unique combination of postural abnormalities,16 which may be reflected by highly variable effect of rehabilitation on the balance of such patients. A comparative study of the effectiveness of functional electrostimulation, biofeedback, and kinesiotherapy on various parameters of lower limb muscular strength, walking kinematics, and body balance of stroke patients revealed biofeedback as the most effective of all analyzed methods of treatment.17 On the other hand, the results of available randomized trials did not confirm the efficacy of biofeedback in resuming the mobility of hemiparetic joints.18 Although the results of some preliminary clinical trials seem promising, the studied techniques are relatively new. Thus, the number of randomized trials necessary to ultimately confirm the usefulness of modern task-based feedback technologies in rehabilitation is limited.19 Glanz et al13 thought that the initial case reports and small uncontrolled series on biofeedback therapy in stroke included differences in the treatment, studied populations, outcome measures, random variation, and systematic variation (also known as bias). These constitute the potential sources of explanation for the disparate conclusions in clinical trials. As a result, stroke rehabilitation in particular
began to be widely discussed by health care professionals and intensively develops. Nevertheless, subsequent articles have delineated the lack of objective evidence for the efficacy of various neuromuscular rehabilitative techniques in stroke and the need for further research in the area. Therefore, there is a need for further studies analyzing the effects of biofeedback training on the fitness, including dynamic balance, of stroke patients. The aim of the experiment was to analyze the influence of posturographic platform biofeedback training on the dynamic balance of patients who experienced ischemic stroke.
Materials and Methods In our study, stroke was defined according to the World Health Organization criteria as rapidly developed clinical signs of focal disturbance, lasting more than 24 hours, with no apparent cause other than vascular origin. 21 adult individuals with ischemic stroke
11 subjects with biofeedback training
10 subjects parcipang in a standard hospital treatment
The study included patients treated at the Rehabilitation Center of the Hospital in Bia1ogard, in the Ward of Neurological Rehabilitation with the Stroke Division. During the designing stage of the study, we strived to provide maximal homogeneity of examined group. Participants were in the subacute phase (functional rehabilitation) and did not possess cognitive or executive impairment or aphasia precluding contact; additionally, the subjects were capable of independent walking and did not have any other conditions associated with balancing disorders. The age of the patients ranged between 55 and 65 years. The group included women and men who were randomized to the experimental (n 5 11) and control group (n 5 10). All the patients experienced ischemic stroke with right- or left-sided hemiparesis, with no laryngologic or ophthalmologic problems. Participation in the study was voluntary and every subject expressed the written consent to take part in the experiment, after receiving written information about the process of examination and participation in an exercise group. The study was approved by the Local Committee of Ethics in Research.
Pre- and Post-training Measurements Control group was subjected to measurements solely at admission and discharge. The measurements of the experimental group were taken at the same time points, but the participants from this group practiced maintenance of body balance (forced sway training) on GOOD
INFLUENCE OF POSTUROGRAPHIC PLATFORM BIOFEEDBACK
3
Figure 1. Pathways covered by the vertical projections of participants’ gravity center during biofeedback training.
BALANCE GB300/GB200 posturographic platform (Metitur Oy, Jyvaskyla, Finland) on daily basis. The level of dynamic balance was determined with Timed Up and Go Test, which uses the time needed by the person to rise independently from a chair where he/she was seated with arms crossed on the chest, walk 3 m, turn around 180 , walk back to chair, and sit down independently in the starting position.20,21 This test is widely used to determine the risk of falling in diseased and older individuals.22,23
Procedure of Training The experiment lasted for 15 days. During the ‘‘forced sway training,’’ the subject stood straight on a posturographic platform with arms held along the trunk. Subsequently, the participant swayed to the extent and direction determined by computer software.24 A screen showing graphical representation of the vertical projection of one’s center of gravity was located in front of the subject, 2.5 m away and 1.5 m above the ground. This point moved in accordance with the direction and extent of sways performed by the participant standing on the platform. Upper part of the screen corresponded to the
anterior part of the platform. Participant’s task pertained to swaying and displacing the vertical projection of his/ her center of pressure so that its image on the screen (point) fit into the required area (square). The square where the participants were instructed to place the center of gravity was marked by a cross. The intended pathway of movement of the center of gravity was projected on the screen, and each successive target square was marked with a consecutive number: ‘‘1,’’ ‘‘2,’’ [.], ‘‘8’’ (Fig 1). The patient had to displace his/her center of gravity in such a way that the corresponding point touched the square with the cross, which was confirmed by a sound signal. Each exercise started with placing the point illustrating the center of gravity in the first square and ended after reaching the last square of a given pathway. In each case, the patient returned to the baseline position (the area in the center of the screen labeled as no. 1) after reaching the next test area.
Statistical Analyses Statistical analyses were performed using Statistica 7 software (StatSoft, Krak ow, Poland), and statistical
Table 1. Baseline characteristics of study subject and difference’s level of UGT E
K
U test
Z
P value
18.9 20.0 16.0-21.0
21.0 20.5 17.0-25.0
31.0
21.7
.097
18.1 17.5 16.0-20.0
20.2 19.0 17.0-25.0
11.5
21.2
.241
21.0 21.0 21.0-21.0
21.8 22.0 20.0-25.0
6.0
2.3
.765
Characteristics UGT (sec) right- and left-sided hemiparesis Mean Median Range UGT (sec) right-sided hemiparesis Mean Median Range UGT (sec) left-sided hemiparesis Mean Median Range
Abbreviation: sec, seconds; UGT, Timed Up and Go Test.
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The results of analysis for groups ‘‘E’’ and ‘‘K’’ with right-sided hemiparesis were found to be Z 5 1.61, P 5.107, and with left-sided hemiparesis, Z 5 .74, P 5.456.
Discussion
Figure 2. Changes in the level of dynamic balance in groups ‘‘E’’ and ‘‘K’’ among right- and left-sided hemiparesis patients. Abbreviations: (s), seconds; UGT, Timed Up and Go Test.
significance was defined as a P value of .05 or less. For each parameter determined in this way, a mean, medium, and range were calculated for the whole group of subjects. To determine the significance of differences between experimental and control groups, the Mann–Whitney test was used. For the analysis of variation of results in pretest and post-test, Wilcoxon matched-pair rank test was used.
Results Data presented in Table 1 suggests that before the training program patients who were randomly selected to groups ‘‘E’’ and ‘‘K’’ did not differ significantly regarding the level of dynamic balance (P . .05). The measurements taken after 15 days of rehabilitation suggest that the score of dynamic balance in the group subjected to biofeedback training improved to a markedly greater extent (Z 5 2.01) as compared with conventionally rehabilitated group (Fig 2). The documented intergroup differences in post-training changes proved statistically significant (P , .05). Participation in biofeedback training exerted stronger effect on the dynamic balance of patients who experienced the stroke of the left hemisphere with right-sided hemiparesis than in those with right hemisphere stroke and left-sided hemiparesis (Fig 3).
Our experiment revealed significant, positive influence of biofeedback training on the selected component of functional fitness, that is, the dynamic balance of ischemic stroke patients. Our findings suggest that enriching traditional rehabilitation with biofeedback-based exercise should be taken into consideration. Previous studies on the efficacy of biofeedback training on posturographic force plates showed an improvement in postural stability measured on the platform. However, the application of biofeedback to other activities still remains controversial. Some authors consider it effective,13,25 whereas others do not.26,27 Our study documented relatively large and statistically significant (P 5 .044) differences in the degree of body balance changes in the group subjected to biofeedback training and the controls. Therefore, as body balance disorders and falls occur frequently enough to be considered a significant problem in stroke rehabilitation, such forms of rehabilitation should be implemented.7 Thus, postural strategies should be developed and included in rehabilitation programs. The positive effects of biofeedback regarding the rehabilitation of stroke patients were already reported previously.15,28,29 However, so far, the mechanism through which biofeedback may support the rehabilitation of the stroke patient is not clear; in fact, it may be mediated by various mechanisms. Perhaps, this constitutes the reason for poorly developed rehabilitation of balance in those patients. It is likely that motor training can promote plastic changes in injured motor networks even at a chronic stage of illness. However, simple interventions such as repetitive movement practice fail to induce profound plastic changes.30 It appears that skill learning must be present to promote cortical plasticity.31 In fact, most of the functional recovery after a stroke may represent actual relearning of the skills with the injured brain. Therefore, demanding tasks should be given to the patient (his/her brain), forcing him/her to learn something new, for example, new (for stroke-affected brain) movements.
Figure 3. Changes in the level of dynamic balance in individuals from groups ‘‘E’’ and ‘‘K’’ with right- or left-sided hemiparesis. Abbreviations: (s), seconds; UGT, Timed Up and Go Test.
INFLUENCE OF POSTUROGRAPHIC PLATFORM BIOFEEDBACK
Swaying the body in directions defined by computer software satisfies this criterion. Learning is reflected by the strengthening of existing neural pathways on one hand and by the new functional and structural changes on the other, thus, resulting in the expression of neuroplasticity.32 However, our findings are not consistent with all previously published reports. According to Barclay-Goddard et al,33 force platform feedback (visual or auditory) improved stance symmetry but not sway in standing, clinical balance outcomes, or measurements of independence. Also, Geiger et al27 questioned the efficacy of biofeedback training. In their 4-week experiment, an improvement in balance and mobility was documented both in the experimental group trained on the NeuroCom Balance Master and in the controls. However, no additional effects were found in the group that received visual biofeedback/forceplate training combined with other physical therapy. One explanation of this finding is that balance retraining is very context or task specific.34 Each patient is different; moreover, we know that although physical training can lead to neurofunctional adaptation within a matter of minutes, long-term representational changes may take days or weeks of practice.35 This could be the reason behind such variation in the outcomes of experiments conducted among the stroke patients. Furthermore, it cannot be excluded that the reason behind discrepancies between previously published studies includes the site of the stroke, which was not always considered in some experiments. Our study revealed that the outcome of rehabilitation varies depending on the stroke site. Although the effectiveness of biofeedback training was relatively strong (but no statistically significant) among patients with right hemiparesis, the rehabilitation of patients with the left hemiparesis subjected to biofeedback training was reflected by a similar outcome as in the untrained controls. Therefore, the side of the stroke significantly modulated the efficacy of biofeedback-extended rehabilitation on a posturographic platform. Left-sided hemiparesis was associated not only with worse baseline scores but also gives a worse prognosis in the rehabilitation process. Wade et al36 observed that patients with right hemiplegia attended rehabilitation longer. Although right hemiplegia was associated with aphasia, and left hemiplegia with spatial disorder and loss of sitting balance, these associations were not strong enough to affect functional recovery. The research of Sonde et al37 on the low transcutaneous electrical nerve stimulation treatment of poststroke paretic arm indicates that the site of lesion plays a role in prognosis/outcome; this issue requires further investigation.
Conclusions Methods based on biofeedback training can significantly improve the efficacy of standard rehabilitation in ischemic stroke patients. The utilization of feedback
5
mechanisms during training on a posturographic platform can be reflected by enhanced stimulation and further improvement of the control of performed motor tasks. The effect of proposed training is the improvement in movement control during the center of gravity displacement. This in turn will be reflected by lower risk of losing balance and falling, both of which frequently occur in stroke patients.
References 1. Ryan AS, Dobrovolny CL, Silver KH, et al. Cardiovascular fitness after stroke: role of muscle mass and gait deficit severity. J Stroke Cerebrovasc Dis 2000;9:185-191. 2. Teasell R, Foley N, Fisher J, et al. The incidence, management, and complications of dysphagia in patients with medullary strokes admitted to a rehabilitation unit. Dysphagia 2002;17:115-120. 3. Rabadi MH, Rabadi FM, Peterson M. An analysis of falls occurring in patients with stroke on an acute rehabilitation unit. Rehabil Nurs 2008;33:104-109. 4. Olsson E, L€ ofgren B, Gustafson Y, et al. Validation of a fall risk index in stroke rehabilitation. J Stroke Cerebrovasc Dis 2005;14:23-28. 5. Harris JE, Eng JJ, Marigold DS, et al. Relationship of balance and mobility to fall incidence in people with chronic stroke. Phys Ther 2005;85:150-158. 6. Sze K, Wong E, Leung HY, et al. Falls among Chinese stroke patients during rehabilitation. Arch Phys Med Rehabil 2001;82:1219-1225. 7. Nyberg L, Gustafson Y. Patient falls in stroke rehabilitation. A challenge to rehabilitation strategies. Stroke 1995; 26:838-842. 8. Tsur A, Segal Z. Falls in stroke patients: risk factors and risk management. IMAJ 2010;12:216-219. 9. Campbell GB, Matthews JT. An integrative review of factors associated with falls during post-stroke rehabilitation. J Nurs Scholarsh 2010;42:395-404. 10. Czernuszenko A. Risk factors for falls in post-stroke patients treated in a neurorehabilitation ward. Neurol Neuroch Pol 2007;41:28-35. 11. Rogind H, Christensen J, Danneskiold-Samsoe B, et al. Posturographic description of the regaining of postural stability following stroke. Clin Physiol Funct Imaging 2005;25:1-9. 12. Yelnik AP, Le Breton F, Colle FM, et al. Rehabilitation of balance after stroke with multisensorial training: a single-blind randomized controlled study. Neurorehabil Neural Repair 2008;22:468-476. 13. Glanz M, Klawansky S, Chalmers T. Biofeedback therapy in stroke rehabilitation: a review. J R Soc Med 1997; 90:33-39. 14. Do gan-Aslan M, Nakipo glu-Y€ uzer GF, Do gan A, et al. The effect of electromyographic biofeedback treatment in improving upper extremity functioning of patients with hemiplegic stroke. J Stroke Cerebrovasc Dis 2012; 21:187-192. 15. Intiso D, Santilli V, Grasso MG, et al. Rehabilitation of walking with electromyographic biofeedback in footdrop after stroke. Stroke 1994;25:1189-1192. 16. Horak FB. Postural orientation and equilibrium: what do we need to know about neural control of balance to prevent falls? Age Ageing 2006;35(Suppl 2):ii7-ii11. 17. Ghasemi E, Shaygannejad V, Jokar S, et al. The effectiveness of functional electrical stimulation (FES), biofeedback
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and exercise therapy on various parameters of lower limb muscle strength, kinematics of gait and balance in stroke patients: a comparative study. JRRS 2010;6:1-2. Glanz M, Klawansky S, Stason W, et al. Biofeedback therapy in poststroke rehabilitation: a meta-analysis of the randomized controlled trials. Arch Phys Med Rehabil 1995;76:508-515. Huang H, Wolf SL, He J. Recent developments in biofeedback for neuromotor rehabilitation. JNER 2006;3:11. Rikli RE, Jones CJ. Development and validation of a functional fitness test for community-residing older adults. J Aging Phys Act 1999;7:129-161. Rikli RE, Jones CJ. Senior fitness test manual. California State University, Fullerton; Champaign, IL: Human Kinetics; 2001. Faria CD, Teixeira-Salmela L, Silva EB, et al. Expanded Timed Up and Go Test with subjects with stroke: reliability and comparisons with matched healthy controls. Arch Physic Med Rehabil 2012;93:1034-1039. Tiago AS, Meira DM, Rico NC, et al. Accuracy of Timed Up and Go Test for screening risk of falls among community-dwelling elderly. Braz J Phys Ther 2012; 16:381-386. Maciaszek J, Osi nski W, Szeklicki R, et al. Effect of tai chi on body balance: randomised controlled trial in men with osteopenia or osteoporosis. AJCM 2007;35:1-9. Cheng PT, Wu SH, Liaw MY, et al. Symmetrical bodyweight distribution training in stroke patients and its effect on fall prevention. Arch Phys Med Rehabil 2001; 82:1650-1654. Bonan IV, Colle FM, Guichard JP, et al. Reliance on visual information after stroke. Part I: balance on dynamic posturography. Arch Phys Med Rehabil 2004;85:268-273. Geiger RA, Allen JB, O’Keefe J, et al. Balance and mobility following stroke: effects of physical therapy interventions with and without biofeedback/forceplate training. Phys Ther 2001;81:995-1005.
28. Sackley CM, Bagully BI. Visual feedback after stroke with balance performance monitor: two single case studies. Clin Rehabil 1993;7:189-195. 29. Srokowska A, Srokowski G, Kuczma W, et al. Ocena _ skutecznosci biologicznego sprze˛zenia zwrotnego w cwiczeniach na Platformie MTD control jako czynnika wspomagaja˛cego fizjoterapie˛ u os ob po przebytym udarze m ozgu. Balneol Pol 2008;50:116-124. 30. Plautz EJ, Milliken GW, Nudo RJ. Effects of repetitive motor training on movement representations in adult squirrel monkeys: role of use versus learning. Neurobiol Learn Mem 2000;74:27-55. 31. Zhuang P, Dang N, Waziri A, et al. Implicit and explicit learning in an auditory serial reaction time task. Acta Neurol Scand 1998;97:131-137. 32. Pascual-Leone A, Amedi A, Fregni F, et al. The plastic human brain cortex. Annu Rev Neurosci 2005;28: 377-401. 33. Barclay-Goddard R, Stevenson T, Poluha W, et al. Force platform feedback for standing balance training after stroke. Cochrane Database Syst Rev 2004;CD004129. 34. Shumway-Cook A. Critical analysis of measurements in balance: a clinical approach. In: Proceedings of the 16th Annual Eugene Michels Researchers’ Forum, American Physical Therapy Association Combined Sections Meeting, Atlanta, GA. Alexandria, VA: American Physical Therapy Association 1996:5-8. 35. Bolognini N, Pascual-Leone A, Fregni F. Using noninvasive brain stimulation to augment motor traininginduced plasticity. JNER 2009;6:8-21. 36. Wade DT, Hewer RL, Wood VA. Stroke: influence of patient’s sex and side of weakness on outcome. Arch Phys Med Rehabil 1984;65:513-516. 37. Sonde L, Bronge L, Kalimo H, et al. Can the site of brain lesion predict improved motor function after low-TENS treatment on the post-stroke paretic arm? Clin Rehabil 2001;15:545-551.
The aim of the experiment was to analyze the influence of posturographic platform biofeedback training on the dynamic balance of patients who experienced ischemic stroke. The study included 21 patients treated at the Rehabilitation Center of the District Hospital in Bia1ogard, in the Ward of Neurological Rehabilitation with the Stroke Division. The age of the patients (11 in the experimental and 10 in the control group) ranged between 55 and 65 years. The level of dynamic balance was determined with Timed Up and Go Test. The experimental group was subjected to the biofeedback training, practicing maintenance of body balance (forced sway training) on posturographic platform for 15 consecutive days. The perception of dynamic balance in the group subjected to biofeedback training improved to a markedly greater extent (P , .05) as compared with conventionally rehabilitated group. Participation in biofeedback training exerted stronger effect on the dynamic balance of patients who experienced the stroke of the left hemisphere with right-sided hemiparesis than in those with right hemisphere stroke and left-sided hemiparesis. The utilization of feedback mechanisms during training on a posturographic platform can be reflected by enhanced stimulation and further improvement of the control of performed motor tasks. Key Words: Stroke—biofeedback—body balance—adults— posturography. Ó 2014 by National Stroke Association
Introduction Stroke constitutes an important cause of decreased functional capacity in humans.1 Among numerous consequences of the stroke, marked decrease in the perception of body balance and ability to maintain correct spatial orientation are frequently mentioned. These balance disorders can be reflected by an increased risk of falling, which is particularly high in neurologic patients.2-4 Not only are such disorders very frequent but can also persist for a considerable time after the stroke episode.5 From the *Department of Theory of Physical Education and Anthropomotorics, University School of Physical Education in Pozna n, Pozna n; and †Neurological Rehabilitation Unit, Rehabilitation Center of the Hospital in Bia1ogard, Poland. Received July 9, 2013; revision received September 4, 2013; accepted October 14, 2013. Address correspondence to Janusz Maciaszek, PhD, Department of Theory of Physical Education and Anthropomotorics, University School of Physical Education in Pozna n, ul. Kr olowej Jadwigi 27/39, 61–871 Pozna n, Poland. E-mail: [email protected]. 1052-3057/$ - see front matter Ó 2014 by National Stroke Association http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2013.10.029
Noticeably, the balance disorders markedly affect the patient’s daily living activities. Despite preventive measures, falls are significantly more frequent in stroke patients than in healthy individuals.6 Nyberg and Gustafson7 analyzed the risk of falling among 161 patients subjected to geriatric rehabilitation after the stroke and revealed that 39% of the subjects experienced falling. Of note is the high variability of factors that play a direct role in falling of such patients. According to Tsur and Segal,8 most documented falls affect patients who suffer from decreased muscular tone (70%), paresis (54%), or unilateral hypoesthesia. Other factors that increase the risk of falling in stroke patients include sedatives or neuroleptics, hemianopia, loss of vision, and visual agnosia. Campbell and Matthews9 published a comprehensive review of experiments addressing the potential risk factors of falling during hospital rehabilitation of men and women after stroke. The authors concluded that the specific risk of falling, such as balance disorders, visuospatial hemineglect, and lack of caution, can be stronger predictors of falling than more general risk factors such as age or impaired sensual function.
Journal of Stroke and Cerebrovascular Diseases, Vol. -, No. - (---), 2014: pp 1-6
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Falls are particularly frequent among individuals with severe neurologic deficits, marked impairment, and neglect syndrome.10 However, the number of falls can be significantly reduced by properly conducted rehabilitation process; moreover, its effects can be observed quite quickly. Rogind et al11 revealed that early implemented rehabilitation activity is reflected by improvement of posturographic parameters during each (1st, 2nd, 4th, and between the 8th and 52nd) week of exercise. The rate and degree of patient’s improvement are modulated by an array of factors, such as the site and size of stroke, patient’s age, general status, and implemented therapeutic and rehabilitation modalities. Yelnik et al12 verified the role of this latter factor, comparing 2 rehabilitation strategies of improving balancing abilities of stroke patients. Their study included 28 patients who experienced the first episode of hemiparesis 3 to 15 months earlier. However, they did not confirm the superiority of multisensorial rehabilitation, as based on higher intensity of balance tasks and exercise during visual deprivation, over the neurodevelopmental theory–based therapy among patients treated at an outpatient setting. Biofeedback methods are used in rehabilitation with increasing frequency.13,14 Biofeedback enables obtaining information on the present state of the body with an aid of various devices. Such information enables voluntary changes to the spatial orientation of the body. The most frequently used types of feedback include visual, acoustic, thermal, strength, electromyographic, and electrokinesiologic biofeedback. Intiso et al15 emphasized the efficacy of this method during the rehabilitation of stroke patients. Nonetheless, each hemiparetic stroke patient may have unique combination of postural abnormalities,16 which may be reflected by highly variable effect of rehabilitation on the balance of such patients. A comparative study of the effectiveness of functional electrostimulation, biofeedback, and kinesiotherapy on various parameters of lower limb muscular strength, walking kinematics, and body balance of stroke patients revealed biofeedback as the most effective of all analyzed methods of treatment.17 On the other hand, the results of available randomized trials did not confirm the efficacy of biofeedback in resuming the mobility of hemiparetic joints.18 Although the results of some preliminary clinical trials seem promising, the studied techniques are relatively new. Thus, the number of randomized trials necessary to ultimately confirm the usefulness of modern task-based feedback technologies in rehabilitation is limited.19 Glanz et al13 thought that the initial case reports and small uncontrolled series on biofeedback therapy in stroke included differences in the treatment, studied populations, outcome measures, random variation, and systematic variation (also known as bias). These constitute the potential sources of explanation for the disparate conclusions in clinical trials. As a result, stroke rehabilitation in particular
began to be widely discussed by health care professionals and intensively develops. Nevertheless, subsequent articles have delineated the lack of objective evidence for the efficacy of various neuromuscular rehabilitative techniques in stroke and the need for further research in the area. Therefore, there is a need for further studies analyzing the effects of biofeedback training on the fitness, including dynamic balance, of stroke patients. The aim of the experiment was to analyze the influence of posturographic platform biofeedback training on the dynamic balance of patients who experienced ischemic stroke.
Materials and Methods In our study, stroke was defined according to the World Health Organization criteria as rapidly developed clinical signs of focal disturbance, lasting more than 24 hours, with no apparent cause other than vascular origin. 21 adult individuals with ischemic stroke
11 subjects with biofeedback training
10 subjects parcipang in a standard hospital treatment
The study included patients treated at the Rehabilitation Center of the Hospital in Bia1ogard, in the Ward of Neurological Rehabilitation with the Stroke Division. During the designing stage of the study, we strived to provide maximal homogeneity of examined group. Participants were in the subacute phase (functional rehabilitation) and did not possess cognitive or executive impairment or aphasia precluding contact; additionally, the subjects were capable of independent walking and did not have any other conditions associated with balancing disorders. The age of the patients ranged between 55 and 65 years. The group included women and men who were randomized to the experimental (n 5 11) and control group (n 5 10). All the patients experienced ischemic stroke with right- or left-sided hemiparesis, with no laryngologic or ophthalmologic problems. Participation in the study was voluntary and every subject expressed the written consent to take part in the experiment, after receiving written information about the process of examination and participation in an exercise group. The study was approved by the Local Committee of Ethics in Research.
Pre- and Post-training Measurements Control group was subjected to measurements solely at admission and discharge. The measurements of the experimental group were taken at the same time points, but the participants from this group practiced maintenance of body balance (forced sway training) on GOOD
INFLUENCE OF POSTUROGRAPHIC PLATFORM BIOFEEDBACK
3
Figure 1. Pathways covered by the vertical projections of participants’ gravity center during biofeedback training.
BALANCE GB300/GB200 posturographic platform (Metitur Oy, Jyvaskyla, Finland) on daily basis. The level of dynamic balance was determined with Timed Up and Go Test, which uses the time needed by the person to rise independently from a chair where he/she was seated with arms crossed on the chest, walk 3 m, turn around 180 , walk back to chair, and sit down independently in the starting position.20,21 This test is widely used to determine the risk of falling in diseased and older individuals.22,23
Procedure of Training The experiment lasted for 15 days. During the ‘‘forced sway training,’’ the subject stood straight on a posturographic platform with arms held along the trunk. Subsequently, the participant swayed to the extent and direction determined by computer software.24 A screen showing graphical representation of the vertical projection of one’s center of gravity was located in front of the subject, 2.5 m away and 1.5 m above the ground. This point moved in accordance with the direction and extent of sways performed by the participant standing on the platform. Upper part of the screen corresponded to the
anterior part of the platform. Participant’s task pertained to swaying and displacing the vertical projection of his/ her center of pressure so that its image on the screen (point) fit into the required area (square). The square where the participants were instructed to place the center of gravity was marked by a cross. The intended pathway of movement of the center of gravity was projected on the screen, and each successive target square was marked with a consecutive number: ‘‘1,’’ ‘‘2,’’ [.], ‘‘8’’ (Fig 1). The patient had to displace his/her center of gravity in such a way that the corresponding point touched the square with the cross, which was confirmed by a sound signal. Each exercise started with placing the point illustrating the center of gravity in the first square and ended after reaching the last square of a given pathway. In each case, the patient returned to the baseline position (the area in the center of the screen labeled as no. 1) after reaching the next test area.
Statistical Analyses Statistical analyses were performed using Statistica 7 software (StatSoft, Krak ow, Poland), and statistical
Table 1. Baseline characteristics of study subject and difference’s level of UGT E
K
U test
Z
P value
18.9 20.0 16.0-21.0
21.0 20.5 17.0-25.0
31.0
21.7
.097
18.1 17.5 16.0-20.0
20.2 19.0 17.0-25.0
11.5
21.2
.241
21.0 21.0 21.0-21.0
21.8 22.0 20.0-25.0
6.0
2.3
.765
Characteristics UGT (sec) right- and left-sided hemiparesis Mean Median Range UGT (sec) right-sided hemiparesis Mean Median Range UGT (sec) left-sided hemiparesis Mean Median Range
Abbreviation: sec, seconds; UGT, Timed Up and Go Test.
J. MACIASZEK ET AL.
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The results of analysis for groups ‘‘E’’ and ‘‘K’’ with right-sided hemiparesis were found to be Z 5 1.61, P 5.107, and with left-sided hemiparesis, Z 5 .74, P 5.456.
Discussion
Figure 2. Changes in the level of dynamic balance in groups ‘‘E’’ and ‘‘K’’ among right- and left-sided hemiparesis patients. Abbreviations: (s), seconds; UGT, Timed Up and Go Test.
significance was defined as a P value of .05 or less. For each parameter determined in this way, a mean, medium, and range were calculated for the whole group of subjects. To determine the significance of differences between experimental and control groups, the Mann–Whitney test was used. For the analysis of variation of results in pretest and post-test, Wilcoxon matched-pair rank test was used.
Results Data presented in Table 1 suggests that before the training program patients who were randomly selected to groups ‘‘E’’ and ‘‘K’’ did not differ significantly regarding the level of dynamic balance (P . .05). The measurements taken after 15 days of rehabilitation suggest that the score of dynamic balance in the group subjected to biofeedback training improved to a markedly greater extent (Z 5 2.01) as compared with conventionally rehabilitated group (Fig 2). The documented intergroup differences in post-training changes proved statistically significant (P , .05). Participation in biofeedback training exerted stronger effect on the dynamic balance of patients who experienced the stroke of the left hemisphere with right-sided hemiparesis than in those with right hemisphere stroke and left-sided hemiparesis (Fig 3).
Our experiment revealed significant, positive influence of biofeedback training on the selected component of functional fitness, that is, the dynamic balance of ischemic stroke patients. Our findings suggest that enriching traditional rehabilitation with biofeedback-based exercise should be taken into consideration. Previous studies on the efficacy of biofeedback training on posturographic force plates showed an improvement in postural stability measured on the platform. However, the application of biofeedback to other activities still remains controversial. Some authors consider it effective,13,25 whereas others do not.26,27 Our study documented relatively large and statistically significant (P 5 .044) differences in the degree of body balance changes in the group subjected to biofeedback training and the controls. Therefore, as body balance disorders and falls occur frequently enough to be considered a significant problem in stroke rehabilitation, such forms of rehabilitation should be implemented.7 Thus, postural strategies should be developed and included in rehabilitation programs. The positive effects of biofeedback regarding the rehabilitation of stroke patients were already reported previously.15,28,29 However, so far, the mechanism through which biofeedback may support the rehabilitation of the stroke patient is not clear; in fact, it may be mediated by various mechanisms. Perhaps, this constitutes the reason for poorly developed rehabilitation of balance in those patients. It is likely that motor training can promote plastic changes in injured motor networks even at a chronic stage of illness. However, simple interventions such as repetitive movement practice fail to induce profound plastic changes.30 It appears that skill learning must be present to promote cortical plasticity.31 In fact, most of the functional recovery after a stroke may represent actual relearning of the skills with the injured brain. Therefore, demanding tasks should be given to the patient (his/her brain), forcing him/her to learn something new, for example, new (for stroke-affected brain) movements.
Figure 3. Changes in the level of dynamic balance in individuals from groups ‘‘E’’ and ‘‘K’’ with right- or left-sided hemiparesis. Abbreviations: (s), seconds; UGT, Timed Up and Go Test.
INFLUENCE OF POSTUROGRAPHIC PLATFORM BIOFEEDBACK
Swaying the body in directions defined by computer software satisfies this criterion. Learning is reflected by the strengthening of existing neural pathways on one hand and by the new functional and structural changes on the other, thus, resulting in the expression of neuroplasticity.32 However, our findings are not consistent with all previously published reports. According to Barclay-Goddard et al,33 force platform feedback (visual or auditory) improved stance symmetry but not sway in standing, clinical balance outcomes, or measurements of independence. Also, Geiger et al27 questioned the efficacy of biofeedback training. In their 4-week experiment, an improvement in balance and mobility was documented both in the experimental group trained on the NeuroCom Balance Master and in the controls. However, no additional effects were found in the group that received visual biofeedback/forceplate training combined with other physical therapy. One explanation of this finding is that balance retraining is very context or task specific.34 Each patient is different; moreover, we know that although physical training can lead to neurofunctional adaptation within a matter of minutes, long-term representational changes may take days or weeks of practice.35 This could be the reason behind such variation in the outcomes of experiments conducted among the stroke patients. Furthermore, it cannot be excluded that the reason behind discrepancies between previously published studies includes the site of the stroke, which was not always considered in some experiments. Our study revealed that the outcome of rehabilitation varies depending on the stroke site. Although the effectiveness of biofeedback training was relatively strong (but no statistically significant) among patients with right hemiparesis, the rehabilitation of patients with the left hemiparesis subjected to biofeedback training was reflected by a similar outcome as in the untrained controls. Therefore, the side of the stroke significantly modulated the efficacy of biofeedback-extended rehabilitation on a posturographic platform. Left-sided hemiparesis was associated not only with worse baseline scores but also gives a worse prognosis in the rehabilitation process. Wade et al36 observed that patients with right hemiplegia attended rehabilitation longer. Although right hemiplegia was associated with aphasia, and left hemiplegia with spatial disorder and loss of sitting balance, these associations were not strong enough to affect functional recovery. The research of Sonde et al37 on the low transcutaneous electrical nerve stimulation treatment of poststroke paretic arm indicates that the site of lesion plays a role in prognosis/outcome; this issue requires further investigation.
Conclusions Methods based on biofeedback training can significantly improve the efficacy of standard rehabilitation in ischemic stroke patients. The utilization of feedback
5
mechanisms during training on a posturographic platform can be reflected by enhanced stimulation and further improvement of the control of performed motor tasks. The effect of proposed training is the improvement in movement control during the center of gravity displacement. This in turn will be reflected by lower risk of losing balance and falling, both of which frequently occur in stroke patients.
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