Authors: Hwang-Jae Lee, MSc, PT Ki-Hun Cho, PhD, PT Wan-Hee Lee, PhD, PT
Stroke
Affiliations: From the Department of Physical Therapy, College of Health and Welfare, Sahmyook University, Seoul, Republic of Korea (H-JL, W-HL); and Department of Physical Therapy, Seoul Bukbu Hospital, Seoul, Republic of Korea (K-HC).
Correspondence: All correspondence and requests for reprints should be addressed to: Wan-Hee Lee, PhD, PT, Department of Physical Therapy, College of Health and Welfare, Sahmyook University, 26-12 Kongnung 2-dong Hwarangro-815 Nowon-gu, Seoul, Republic of Korea, 139-742.
ORIGINAL RESEARCH ARTICLE
The Effects of Body Weight Support Treadmill Training with Power-Assisted Functional Electrical Stimulation on Functional Movement and Gait in Stroke Patients
Editor’s Note
ABSTRACT
Accepted as a Rapid Communication on September 30, 2013.
Lee H-J, Cho K-H, Lee W-H: The effects of body weight support treadmill training with power-assisted functional electrical stimulation on functional movement and gait in stroke patients. Am J Phys Med Rehabil 2013;92:1051Y1059.
Disclosures: Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article.
0894-9115/13/9212-1051/0 American Journal of Physical Medicine & Rehabilitation Copyright * 2013 by Lippincott Williams & Wilkins DOI: 10.1097/PHM.0000000000000040
Objective: The aim of the current study was to examine the effect of body weight support treadmill training (BWSTT) with power-assisted functional electrical stimulation on functional movement and gait in stroke patients. Design: Thirty stroke patients were randomly assigned to either the experimental group (n = 15) or the control group (n = 15). All subjects participated in the same standard rehabilitation program. In addition, the experimental group participated in BWSTTwith power-assisted functional electrical stimulation for 30 mins per day, five times a week, for 4 wks, and those in the control group participated in BWSTT for 30 minutes per day, five times a week, for 4 wks. Functional movement was assessed using the Berg Balance Scale, the Timed Up and Go test, and the Stroke Rehabilitation Assessment of Movement. Gait ability was assessed using an electrical walkway system.
Results: Significant differences in the time factor for functional movement and gait (P G 0.05) were observed in the experimental and control groups. For the group time interaction, significant improvements were observed in the functional movement (Berg Balance Scale [10.93 vs. 6.00], Timed Up and Go test [j9.25 vs. j5.25 secs], and Stroke Rehabilitation Assessment of Movement scores [14.07 vs. 9.80]) and gait (velocity [40.07 vs. 18.64 cm/sec], cadence [30.57 vs. 17.75 steps per minute], paretic side step length [19.36 vs. 8.46 cm], and stride length [30.57 vs. 12.71 cm]) (P G 0.05).
Conclusions: The findings of the current study demonstrated the efficacy of BWSTT with power-assisted functional electrical stimulation on the functional movement and gait ability in stroke patients. Therefore, the authors suggest that power-assisted functional electrical stimulation may be an effective method for the improvement of functional movement and gait ability of stroke patients when added to BWSTT. Key Words: www.ajpmr.com
Body Weight Support Treadmill, Functional Electric Stimulation, Gait, Stroke
Body Weight Support Treadmill with FES Copyright © 2013 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
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espite extensive rehabilitation, many stroke patients live with dependent ambulation and limited activities of daily living.1 Thus, many therapeutic approaches for achievement of independent ambulation in stroke patients have been attempted.2,3 In particular, among the various therapeutic approaches, a partial body weight support (BWS) system continuously has been used for the improvement of gait ability in stroke patients.4Y7 BWS provides partial body weight to the lower extremities, thereby facilitating walking in patients with neurologic damages who cannot support the full weight on the lower extremity.5 Visintin and Barbeau8 reported that partial weight loading of the lower extremities induced improvement of gait ability in stroke patients. In addition, Mudge et al.9 demonstrated the effectiveness of BWS treadmill training (BWSTT) on balance control. However, interestingly, gait speed did not show significant change after BWSTT because compensatory movement patterns by induced foot drop can lead to slowed gait velocity and limited functional movement.9,10 To compensate for the lack of ankle dorsiflexor activation, BWSTT combined with functional electrical stimulation (FES) was attempted.11,12 FES is typically delivered to ankle dorsiflexors to correct foot drop during the swing phase, thereby promoting post-stroke gait deficits in other stance and swing phases.13 Hesse et al.14 investigated the effect of BWSTT combined with multichannel electrical stimulation in stroke patients and reported improvements of the gait ability, including gait speed, cadence, and stride length. In another study, the combination of BWSTT and FES led to improvements in motor recovery and seemed to have improved the gait pattern of stroke patients.15 Recently, a new FES system (power-assisted FES [PAFES] system) is being used as an approach for improvement of functional ability in stroke patients. PAFES induces greater muscle contraction by an electrical stimulation, which is regulated by the control system in proportion to the integrated electromyography (EMG) signal.16 Proprioceptive sensory feedback has been reported to play an important role in PAFES.17 Hara et al.16 reported that PAFES was effective in reducing the spasticity of the paretic upper extremity in stroke patients. In addition, another study reported that PAFES can effectively improve wrist and finger extension and shoulder flexion.17 Despite the fact that reduced walking ability is one of the major disabilities in stroke patients, investigations of PAFES for improvement of walking ability are insufficient. To the best of the authors’
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knowledge, this is the first report using PAFES for improvement of walking ability in stroke patients. The purpose of this study was to investigate the effect of BWSTT with PAFES (BWT-PAFES) on functional movement and gait in stroke patients. The authors hypothesized that stroke patients would show improvement in functional movement and gait performance after 4 wks of BWT-PAFES.
METHODS Participants Thirty-five stroke patients undergoing standard rehabilitation were recruited on a voluntary basis from the inpatient rehabilitation hospital. The inclusion criteria for this study were categorized as (1) a diagnosis of stroke (cerebral cortex lesion: ischemic brain injury or intracerebral hemorrhage) shown by magnetic resonance imaging or computed tomography, (2) at least 5 degrees of ankle passive range of motion and at least 1 of 5 in ankle dorsiflexion muscle strength (manual muscle test),18 (3) sufficient cognition to follow simple instructions and understand the content and purpose of the study (Korean version of the MiniYMental State Examination score of Q24 points), (4) ability to walk 10 m independently with or without use of an assistive device, (5) absence of a musculoskeletal condition that could potentially affect the ability to walk safely, (6) a Brunnstrom stage between 1 and 4 for the lower extremity, (7) absence of a hearing disorder, and (8) no skin allergy to electric stimulation. The exclusion criteria were (1) excessive spasticity in the affected leg, as defined with a score of 3 or greater on the Modified Ashworth Spasticity Scale; (2) any comorbidity or disability other than those that would preclude gait training; (3) participation in other studies or rehabilitation program; (4) severe heart disease or uncontrolled hypertension and pain; and (5) any neurologic or orthopedic diseases that may interfere with the study. Five of the 35 potential subjects were excluded because they failed to meet the inclusion criteria (uncontrolled hypertension, hearing disorder, and knee pain) or they met the exclusion criteria (participation in other studies). Finally, a total of 30 subjects were included in this study. The subjects were briefed on the experimental procedure, and written consents were collected from all subjects before the experiment. Human subject ethical approval was obtained from the relevant committee in the Sahmyook University institutional review board before conducting the experiment.
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Procedure This study used a randomized pretest and posttest control group design. Pretest and posttest analyses consisted of functional movement and gait ability. After the pretest, all participants were randomized to the BWT-PAFES group (n = 15) or the BWSTT group (n = 15). Randomization was computer generated using a basic random number generator. All subjects participated in a training program for 4 wks after the pretest. In addition, the posttest was conducted 3 days after the end of the intervention period. All measurements were performed while the patients were in the admitted rehabilitation ward, and the assessor was blinded. All subjects participated in the same standard rehabilitation program, which consisted of conventional physical therapy and occupational therapy. Conventional physical therapy, including increased trunk stability (bridge exercise and gym ball exercise), lower extremity muscle strength (standing on the paretic leg and going up and down the stairs),
and gait (gait pattern reeducation and parallel bar gait), was performed for 60 mins per day, five times a wk, for 4 wks. Occupational therapy, an upper extremity training program for activities of daily living (stretching, active-assisted range of motion, and reaching and grasping), was performed for 30 mins per day, five times a week, for 4 wks. In addition, the subjects in the experimental group participated in BWT-PAFES and the subjects in the control group participated in BWSTT. After pretest, training (BWTPAFES and BWSTT) and standard rehabilitation programs provided to the BWT-PAFES and BWSTT groups were conducted in a different therapeutic building. Thus, none of the subjects were aware of which group they were in. In addition, treadmill trainers and therapists (physical and occupational therapy) were unaware of the group allocation. Training sessions of both the experimental and control groups lasted 30 mins with an optional break time (3 mins). All participants successfully completed the study protocol, and the attendance rate was 100%
FIGURE 1 Flow diagram of the study. www.ajpmr.com
Body Weight Support Treadmill with FES Copyright © 2013 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
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for the 4-wk intervention. The flow chart of the study is shown in Figure 1.
Intervention BWSTT with PAFES PAFES, a portable two-channel neuromuscular stimulator (PAS; OG Giken, Okayama, Japan), was used for delivery of electrical stimulation during BWSTT. The PAFES device induces greater muscle contraction by electrical stimulation in proportion to the integrated EMG signal.16 The PAFES system was composed of a setting and input system and a portable stimulator. The setting and input system and the portable stimulator work together via a Bluetooth system connection, and the surface electrodes were connected to the portable stimulator. The surface electrodes pick up the EMG signals (threshold intensity) as the target muscle starts to contract. The setting and input system evaluates the amount of activity in the target muscle and determines whether the stimulation intensity is proportional to the muscle activity. In other words, the same surface electrodes detect the EMG signals at the target muscle and stimulate them with a stimulus intensity proportional to the integrated EMG signals. However, when there is no voluntary contraction to the target muscle, the PAFES system does not work. Sensitivity of the EMG signal can be set from 1,000 to 10,000 times, and stimulation output had a rectangular-wave biphasic pulse duration of 50 and an adjustable voltage between 0 and 160 V peak to peak. The PAFES has two channels; however, this study used only one channel. According to previous evidence on FES targeting stroke patients, the improvement of swing phase in the gait cycle, when FES was applied to both the dorsiflexor and plantarflexor
muscles, was less than when FES was applied to the dorsiflexor muscle alone.13 On the basis of a previous study, surface electrode was applied to the tibialis anterior muscle (Fig. 2A). Before the start of intervention, the subjects participated in an assessment for the detection of threshold intensity. The PAFES system was set on the basis of the detected threshold intensity. In addition, the trainer checked the settings of the PAFES device once a week and modified the threshold intensity settings for individuals as needed. BWT-PAFES was performed targeting the tibialis anterior muscle of the affected lower limb during BWS treadmill walking but will not work when the target muscle has no muscle contraction (Fig. 2B). The portable stimulator was fixed without shaking using a strap to the thigh. Because the portable stimulator is light, the patients could perform BWT-PAFES without interference. In addition, BWT-PAFES started with 40% BWS condition using a harness (walking harness; LINAK, Nordborg, Denmark).18 The BWS was decreased progressively by a 10% increment a week for the subjects’ muscle activity during BWT-PAFES.19,20 All subjects recorded walking speeds on the treadmill before and after the intervention. The mean treadmill speed for the subjects during the initial testing was 0.4 m/sec, and if the subjects maintained a good gait pattern, the treadmill speed was increased progressively as rapidly as possible. In this study, a good gait pattern indicates an increase in the single-limb support time on the paretic leg. According to a previous study on BWSTT of stroke patients, increment of single-limb support time on the paretic limb can lead to weight support on the paretic side.21 Thus, gait training to improve walking ability in hemiparetic individuals should provide increased single-limb support time on the
FIGURE 2 A, The location of surface electrode. B, Setting for the BWT-PAFES.
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paretic limb.21 All subjects received verbal cues during the intervention to maintain good gait pattern. Instructions, such as trunk alignment, step length, and knee flexion for the swing phase, were given according to the subjects’ abilities. The change for BWS and treadmill speed was applied with the same method in both the BWTPAFES and BWSTT groups. According to the recorded data, the mean treadmill speed was increased by 10% a week. In the final week of training, the mean treadmill speed and BWS was 0.6 m/sec and 10%, respectively. Emergency stop devices were operated for the subjects’ safety during intervention. In addition, a trainer watched the subjects carefully beside the treadmill during an intervention to prevent the subjects from experiencing a fall during training and for identification of any other signs of excessive fatigue.22 The subjects in the experimental group underwent BWT-PAFES for 30 mins per day, five times a week, for 4 wks, and those in the control group underwent BWSTT for 30 mins per day, five times a week, for 4 wks. In BWSTT, the treadmill walking speed, amount of BWS, and verbal cue during treadmill walking were controlled using a method similar to that used in the experimental group. However, PAFES was not applied in the control group.
Measurement Tools Functional Movement Ability. Functional movement was measured using the Berg Balance Scale (BBS), the Timed Up and Go test (TUG), and the Stroke Rehabilitation Assessment of Movement (STREAM). The BBS is a valid and reliable instrument for the measurement of balance ability in elderly or stroke patients. BBS scores range from 0 to 56 points, and higher scores indicate better dynamic balance.23 The TUG is measured as time (seconds) required for performance of the following series of actions: stand up from a chair, walk 3 m at normal walking speed, turn around, walk back, and sit down. Use of assistive devices was permitted when necessary.24 The STREAM is a clinical measurement tool for the evaluation of the recovery of voluntary movement and basic mobility after stroke. The final version of the STREAM measure consists of 30 items or test movements that are equally distributed among the three subscales: 10 items assessing upper limb movements, 10 items assessing lower limb movements, and 10 items for basic mobility. Limb movements are scored on a 3-point scale. Mobility items are scored on a 4point scale similar to that used for scoring limb movements except that a category has been added to www.ajpmr.com
allow for independence with the help of a mobility aid. Thus, the maximum raw total STREAM score is 70, with each of the limb subscales scored out of 20 points and the mobility subscale scored out of 30 points.25 The reliability of the STREAM scores was demonstrated by generalizability correlation coefficients of 0.99 for the total scores and 0.96 to 0.99 for the subscale scores.25 Gait Ability. Gait ability was measured using an electrical walkway system (GAITRite; CIR System Inc, New Jersey). The GAITRite system provided temporal and spatial gait parameters via an electronic walkway connected to the serial port of a personal computer. The standard GAITRite walkway contained six sensor pads encapsulated in a roll-up carpet with an active area of 3.66 m length and 0.61 m width.26 The participants walked across a walkway over the mat under three trials at a selfdetermined comfortable gait speed. A resting period (2 mins) was provided between the measurements to offset any potential fatigue effects. The subjects initiated and terminated walking for a minimum of 3 m from the start to the end of the walkway to maintain gait speed on the mat. A verbal command was given to initiate walking, and one of the examiners accompanied the subjects to prevent them from falling while walking. The subjects were allowed to use assistive devices that were used during testing. All values were averaged for the three trials. The gait parameters recorded were as follows: velocity, cadence, paretic side step length, and stride length.
Data Analysis Statistical analyses were performed using the Statistical Package for the Social Sciences, version 15.0. Descriptive statistics were used to describe patient characteristics. The Shapiro-Wilk test was used to confirm that all outcome variables were normally distributed. Independent t test (for continuous variables), Mann-Whitney U test (for ordinal variables), and W2 test (for categorical variables) were used for comparison of the baseline characteristics of the subjects in both groups. For measures of dependent variables, analysis of variance with mixed design (within-subject factor = time, between subject factor = group) was used to compare each outcome variable between two time points (pretest and posttest). To examine the main effects of the intervention, a two (group) two (time) analysis of variance with repeated measure was performed. A significance level of 0.05 was used in all measurements. Body Weight Support Treadmill with FES
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RESULTS
step length (F = 12.911, P = 0.001), and stride length (F = 14.731, P = 0.001).
Baseline Characteristics General characteristics of the subjects are shown in Table 1. No significant differences in general characteristics and dependent variables were observed between the BWT-PAFES and BTSTT groups.
Changes of Functional Movement and Gait Ability Changes in functional movement and gait ability are shown in Table 2. After 4 wks of intervention, both groups showed a main effect of time on the BBS (F = 135.946, P = 0.000), the TUG (F = 269.769, P = 0.000), the STREAM (F = 340.474, P = 0.000), velocity (F = 152.577, P = 0.000), cadence (F = 119.833, P = 0.000), paretic side step length (F = 84.066, P = 0.000), and stride length (F = 86.492, P = 0.000). In addition, significant differences were observed for the group time interactions of the BBS (F = 11.539, P = 0.002), the TUG (F = 20.431, P = 0.000), the STREAM (F = 10.881, P = 0.003), velocity (F = 20.328, P = 0.000), cadence (F = 15.653, P = 0.000), paretic side
DISCUSSION The current study was conducted to examine the effect of BWT-PAFES on functional movement and gait in stroke patients. After 4 wks of BWT-PAFES, significant improvements in functional movement and gait were observed between the BWT-PAFES and BWSTT groups. In the field of stroke rehabilitation, the effectiveness of treadmill training on functional ability of stroke patients has been demonstrated through previous studies.3,6 In addition, treadmill training for achievement of independent ambulation was used combined with various other approaches.15,27 Treadmill training may have the greatest impact when applied before overground gait training; in particular, it has been identified that the training effect was maximized when combined with other interventions.28 Trueblood27 reported that treadmill training with BWS induced normalization of the gait pattern and postural control in patients with chronic
TABLE 1 Homogeneity test for general characteristics and dependent variables of the subjects (N = 30)
General characteristics Sex Male/female Paretic side Left/right Etiology Infarction/hemorrhage Ankle dorsiflexor,a grade MAS (1/1+/2) Brunnstrom stages (2/3/4) Age, yrs Height, cm Weight, kg Stroke onset duration,b mos MMSE-K, score Dependent variables BBS, score TUG, secs STREAM, score Velocity, cm/sec Cadence, steps per minute P-step length, cm P-stride length, cm
BWT-PAFES (n = 15)
BWSTT (n = 15)
P
12/3
10/5
0.426d
7/8
8/7
0.726d
10/5 2 (1~2)c 5/9/1 5/7/3 52.47 T 9.41 169.26 T 7.92 65.67 T 10.28 4.0 T 0.41 26.53 T 1.96
12/3 2 (1~2)c 4/9/2 3/9/3 56.73 T 7.24 164.21 T 9.35 65.47 T 13.24 4.07 T 1.03 27.07 T 1.98
0.426d 0.539e V V 0.175f 0.122f 0.965f 0.868f 0.465f
34.13 T 3.81 24.36 T 3.85 45.00 T 8.06 35.93 T 20.08 61.97 T 21.02 32.29 T 9.18 62.27 T 19.45
34.27 T 27.30 T 43.40 T 38.08 T 66.55 T 34.49 T 61.29 T
2.66 5.73 7.38 19.64 20.14 10.67 15.98
0.912f 0.110f 0.575f 0.769f 0.547f 0.550f 0.881f
Values are expressed as number or mean T standard deviation. a Measured by manual muscle test. b Durations between stroke onset and pretest. c Median (range). d 2 W test. e Mann-Whitney U test. f Independent t test. MAS, Modified Ashworth Scale; MMSE-K, Korean version of the MiniYMental State Examination; P, paretic side.
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62.27 T 19.45 61.29 T 15.98 92.84 T 18.68 73.10 T 21.71 30.57 T 16.44a,b 12.71 T 7.39a 86.492 (0.000) 14.731 (0.001) T 9.18 T 10.67 T 9.34 T 11.41 T 7.82a,b T 8.77a (0.000) (0.001) 32.29 34.49 51.64 42.94 19.36 8.46 84.066 12.911 61.97 T 21.02 66.55 T 20.14 92.13 T 21.63 84.30 T 23.45 30.15 T 12.43a,b 17.75 T 13.16a 119.833 (0.000) 15.653 (0.000)
Values are expressed as mean T standard deviation. a Significant differences between pretest and posttest, P G 0.05. b Significant differences between the BWT-PAFES group and the BWSTT group, P G 0.05. P, paretic side.
35.93 T 20.08 38.08 T 19.64 76.00 T 19.96 56.72 T 28.81 40.07 T 11.55a,b 18.64 T 14.33a 152.577 (0.000) 20.328 (0.000) 24.36 T 3.85 27.30 T 5.73 15.10 T 3.40 22.04 T 4.79 j9.25 T 2.19a,b j5.25 T 2.63a 269.769 (0.000) 20.431 (0.000) Pretest
BWT-PAFES (n = 15) BWSTT (n = 15) Posttest BWT-PAFES (n = 15) BWSTT (n = 15) Change BWT-PAFES (n = 15) BWSTT (n = 15) F (P) for time factor F (P) for group time interaction
34.13 T 3.81 34.27 T 2.66 45.07 T 3.01 40.27 T 3.60 10.93 T 4.74a,b 6.00 T 3.02a 135.946 (0.000) 11.539 (0.002)
45.00 T 8.06 43.40 T 7.38 59.07 T 6.89 53.20 T 7.55 14.07 T 4.01a,b 9.80 T 3.00a 340.474 (0.000) 10.881 (0.003)
P-Stride Length, cm P-Step Length, cm Cadence, Steps per Minute TUG, secs Test
Group
BBS (Score)
STREAM (Score)
Velocity, cm/sec
Gait Ability Functional Movement
TABLE 2 Comparison of balance, functional movement, and gait ability within groups and between groups (N = 30)
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stroke. Hesse et al.4 reported that the combination of conventional physical therapy and BWSTT was more effective in improving gait ability than was physical therapy only. Previous studies on treadmill training combined with other interventions demonstrated that the repetitive gait pattern generated by treadmill walking induced motor recovery and brain reorganization, and it led to the improvement of functional activity.7,27 In addition, the combination of BWSTT and FES was attempted in stroke rehabilitation. FES can assist in the swing phase of the gait cycle during treadmill walking using electrical currents to activate the nerves innervating paretic lower extremity resulting from stroke.29 BWSTT combined with FES was more comfortable because the placement of the foot during early stance was easier and decreased the participation of the assistant during training.15 Many previous studies have demonstrated positive effects of a combination of BWSTT and FES on walking ability of stroke patients14,15; however, a recent study30 reported that the addition of FES to the BWSTT did not provide any additional benefits in motor function and walking ability. Although FES has been used for improvement of walking ability,29 preprogrammed stimulation of FES induced only cyclic muscle contractions without active participation of the subject.31 Of particular interest, a previous study reported that active participation in motor training is more effective than passive participation in improving functional activity.22 Currently, there is a growing interest in PAFES. PAFES provides stimulation when voluntarily generated EMG signals surpass a preset threshold.16 PAFES has shown a positive effect in paralyzed arm movement and function in stroke patients.16,17 However, efficacy of PAFES for walking remains unknown. Thus, the authors attempted a combination of BWSTT and PAFES used for improvement of walking ability. In this study, greater significant improvements in functional movement were observed in the BWT-PAFES group compared with the BWSTT group. Motor relearning is defined as the reacquisition of motor skills after injury of the central nervous system, and it is known to be facilitated when active repetitive movement was applied.32 Makowski et al.33 reported that FES combined with voluntary effort may have the potential to increase functional movement, and Boyaci et al.31 reported that EMGtriggered stimulation increased the upper limb motor function and functional recovery of stroke patients. The finding from the current study is consistent with that Body Weight Support Treadmill with FES
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from previous studies; the authors believe that the facilitation of motor relearning caused by voluntary movement in PAFES led to an improvement of functional movement of stroke patients. Another finding of the present study is the significant improvement observed in gait ability in the BWT-PAFES group compared with the BWSTT group. A possible reason for the improvement of gait ability between the groups may be the increased somatosensory input and facilitation of neuroplasticity caused by application of PAFES to the ankle dorsiflexor. Embrey et al.34 reported that an electrical stimulation of the dorsiflexor during the swing phase in gait cycle induced normal gait and the achievement of better outcomes of stroke patients. The basic role of PAFES is to assist in the activation of impaired efferent pathways.35 It is based on the sensory-motor integration theory36 that sensory input from movement of an affected limb directly influences the subsequent motor output. In other words, because impairment of the somatosensory input may be the cause of delayed motor recovery in stroke patients, accurate somatosensory input is essential for the achievement of motor recovery.37 According to previous evidence, activation of impaired efferent pathways is maximized when it occurs with active movement.22,31 In addition, increased somatosensory input during walking could provide improvement of gait patterns in stroke patients.38 Thus, it is assumed that an addition of PAFES to BWSTT could lead to an increased somatosensory input by active participation of the ankle dorsiflexor during the BWSTT, thereby leading to an improvement of gait ability. As another possible explanation for the current findings, previous studies on functional magnetic resonance imaging reported that active participation of an active stimulation method exerts a positive effect on neuroplasticity.39,40 However, because functional magnetic resonance imaging was not included as a dependent variable in this study, accurate comparison is difficult. Thus, more research is required to investigate the effect of PAFES on neuroplasticity. The findings of the current study demonstrated a beneficial effect of PAFES applied to the ankle dorsiflexor during BWSTT on functional movement and gait ability in stroke patients; however, it had some limitations. First, a statistical power was not calculated and a small number of subjects were recruited. Therefore, these results cannot be generalized to all stroke patients. Second, long-term follow-up of BWT-PAFES was not considered. Therefore, the authors suggest that further studies
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include long-term follow-up to examine the longterm effect of BWT-PAFES.
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15. Lindquist AR, Prado CL, Barros RM, et al: Gait training combining partial body-weight support, a treadmill, and functional electrical stimulation: Effects on poststroke gait. Phys Ther 2007;87:1144Y54 16. Hara Y, Ogawa S, Muraoka Y: Hybrid power-assisted functional electrical stimulation to improve hemiparetic upper-extremity function. Am J Phys Med Rehabil 2006;85:977Y85 17. Hara Y: Neurorehabilitation with new functional electrical stimulation for hemiparetic upper extremity in stroke patients. J Nippon Med Sch 2008;75:4Y14 18. Barth E, Herrman V, Levine P, et al: Low-dose, EMGtriggered electrical stimulation for balance and gait in chronic stroke. Top Stroke Rehabil 2008;15:451Y55 19. Lamontagne A, Fung J: Faster is better: Implications for speed-intensive gait training after stroke. Stroke 2004;35:2543Y8 20. Sullivan KJ, Knowlton BJ, Dobkin BH: Step training with body weight support: Effect of treadmill speed and practice paradigms on poststroke locomotor recovery. Arch Phys Med Rehabil 2002;83:683Y91 21. Chen G, Patten C, Kothari DH, et al: Gait deviations associated with post-stroke hemiparesis: Improvement during treadmill walking using weight support, speed, support stiffness, and handrail hold. Gait Posture 2005;22:57Y62 22. Cho KH, Lee WH: Virtual walking training program using a real-world video recording for patients with chronic stroke: A pilot study. Am J Phys Med Rehabil 2013;92:371Y84 23. Berg K, Wood-Dauphinee S, Williams JI: The Balance Scale: Reliability assessment with elderly residents and patients with an acute stroke. Scand J Rehabil Med 1995;27:27Y36 24. Ng SS, Hui-Chan CW: The Timed Up & Go test: Its reliability and association with lower-limb impairments and locomotor capacities in people with chronic stroke. Arch Phys Med Rehabil 2005;86:1641Y7 25. Daley K, Mayo N, Wood-Dauphinee S: Reliability of scores on the Stroke Rehabilitation Assessment of Movement (STREAM) measure. Phys Ther 1999; 79:8Y19 26. Menz HB, Latt MD, Tiedemann A, et al: Reliability of the GAITRite walkway system for the quantification of temporo-spatial parameters of gait in young and older people. Gait Posture 2004;20:20Y5 27. Trueblood PR: Partial body weight treadmill training in persons with chronic stroke. NeuroRehabilitation 2001;16:141Y53
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28. Fisher BE, Sullivan KJ: Activity-dependent factors affecting poststroke functional outcomes. Top Stroke Rehabil 2001;8:31Y44 29. Pereira S, Mehta S, McIntyre A, et al: Functional electrical stimulation for improving gait in persons with chronic stroke. Top Stroke Rehabil 2012;19:491Y8 30. Prado-Medeiros CL, Sousa CO, Souza AS, et al: Effects of the addition of functional electrical stimulation to ground level gait training with body weight support after chronic stroke. Rev Bras Fisioter 2011;15:436Y44 31. Boyaci A, Topuz O, Alkan H, et al: Comparison of the effectiveness of active and passive neuromuscular electrical stimulation of hemiplegic upper extremities: A randomized, controlled trial [published online ahead of print]. Int J Rehabil Res 2013 32. Sheffler LR, Taylor PN, Gunzler DD, et al: Randomized controlled trial of surface peroneal nerve stimulation for motor relearning in lower limb hemiparesis. Arch Phys Med Rehabil 2013;94:1007Y14 33. Makowski N, Knutson J, Chae J, et al: Interaction of poststroke voluntary effort and functional neuromuscular electrical stimulation. J Rehabil Res 2013; 50:85Y98 34. Embrey DG, Holtz SL, Alon G, et al: Functional electrical stimulation to dorsiflexors and plantar flexors during gait to improve walking in adults with chronic hemiplegia. Arch Phys Med Rehabil 2010;91:687Y96 35. Roby-Brami A, Bennis N, Mokhtari M, et al: Hand orientation for grasping depends on the direction of the reaching movement. Brain Res 2000;869:121Y9 36. Rosenbaum DA, Meulenbroek RG, Vaughan J: Planning reaching and grasping movements: Theoretical premises and practical implications. Motor Control 2001;5:99Y115 37. Wu CW, Seo HJ, Cohen LG: Influence of electric somatosensory stimulation on paretic-hand function in chronic stroke. Arch Phys Med Rehabil 2006;87:351Y7 38. Lin SI, Hsu LJ, Wang HC: Effects of ankle proprioceptive interference on locomotion after stroke. Arch Phys Med Rehabil 2012;93:1027Y33 39. Shin HK, Cho SH, Jeon HS, et al: Cortical effect and functional recovery by the electromyographytriggered neuromuscular stimulation in chronic stroke patients. Neurosci Lett 2008;442:174Y9 40. von Lewinski F, Hofer S, Kaus J, et al: Efficacy of EMG-triggered electrical arm stimulation in chronic hemiparetic stroke patients. Restor Neurol Neurosci 2009;27:189Y97
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Affiliations: From the Department of Physical Therapy, College of Health and Welfare, Sahmyook University, Seoul, Republic of Korea (H-JL, W-HL); and Department of Physical Therapy, Seoul Bukbu Hospital, Seoul, Republic of Korea (K-HC).
Correspondence: All correspondence and requests for reprints should be addressed to: Wan-Hee Lee, PhD, PT, Department of Physical Therapy, College of Health and Welfare, Sahmyook University, 26-12 Kongnung 2-dong Hwarangro-815 Nowon-gu, Seoul, Republic of Korea, 139-742.
ORIGINAL RESEARCH ARTICLE
The Effects of Body Weight Support Treadmill Training with Power-Assisted Functional Electrical Stimulation on Functional Movement and Gait in Stroke Patients
Editor’s Note
ABSTRACT
Accepted as a Rapid Communication on September 30, 2013.
Lee H-J, Cho K-H, Lee W-H: The effects of body weight support treadmill training with power-assisted functional electrical stimulation on functional movement and gait in stroke patients. Am J Phys Med Rehabil 2013;92:1051Y1059.
Disclosures: Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article.
0894-9115/13/9212-1051/0 American Journal of Physical Medicine & Rehabilitation Copyright * 2013 by Lippincott Williams & Wilkins DOI: 10.1097/PHM.0000000000000040
Objective: The aim of the current study was to examine the effect of body weight support treadmill training (BWSTT) with power-assisted functional electrical stimulation on functional movement and gait in stroke patients. Design: Thirty stroke patients were randomly assigned to either the experimental group (n = 15) or the control group (n = 15). All subjects participated in the same standard rehabilitation program. In addition, the experimental group participated in BWSTTwith power-assisted functional electrical stimulation for 30 mins per day, five times a week, for 4 wks, and those in the control group participated in BWSTT for 30 minutes per day, five times a week, for 4 wks. Functional movement was assessed using the Berg Balance Scale, the Timed Up and Go test, and the Stroke Rehabilitation Assessment of Movement. Gait ability was assessed using an electrical walkway system.
Results: Significant differences in the time factor for functional movement and gait (P G 0.05) were observed in the experimental and control groups. For the group time interaction, significant improvements were observed in the functional movement (Berg Balance Scale [10.93 vs. 6.00], Timed Up and Go test [j9.25 vs. j5.25 secs], and Stroke Rehabilitation Assessment of Movement scores [14.07 vs. 9.80]) and gait (velocity [40.07 vs. 18.64 cm/sec], cadence [30.57 vs. 17.75 steps per minute], paretic side step length [19.36 vs. 8.46 cm], and stride length [30.57 vs. 12.71 cm]) (P G 0.05).
Conclusions: The findings of the current study demonstrated the efficacy of BWSTT with power-assisted functional electrical stimulation on the functional movement and gait ability in stroke patients. Therefore, the authors suggest that power-assisted functional electrical stimulation may be an effective method for the improvement of functional movement and gait ability of stroke patients when added to BWSTT. Key Words: www.ajpmr.com
Body Weight Support Treadmill, Functional Electric Stimulation, Gait, Stroke
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D
espite extensive rehabilitation, many stroke patients live with dependent ambulation and limited activities of daily living.1 Thus, many therapeutic approaches for achievement of independent ambulation in stroke patients have been attempted.2,3 In particular, among the various therapeutic approaches, a partial body weight support (BWS) system continuously has been used for the improvement of gait ability in stroke patients.4Y7 BWS provides partial body weight to the lower extremities, thereby facilitating walking in patients with neurologic damages who cannot support the full weight on the lower extremity.5 Visintin and Barbeau8 reported that partial weight loading of the lower extremities induced improvement of gait ability in stroke patients. In addition, Mudge et al.9 demonstrated the effectiveness of BWS treadmill training (BWSTT) on balance control. However, interestingly, gait speed did not show significant change after BWSTT because compensatory movement patterns by induced foot drop can lead to slowed gait velocity and limited functional movement.9,10 To compensate for the lack of ankle dorsiflexor activation, BWSTT combined with functional electrical stimulation (FES) was attempted.11,12 FES is typically delivered to ankle dorsiflexors to correct foot drop during the swing phase, thereby promoting post-stroke gait deficits in other stance and swing phases.13 Hesse et al.14 investigated the effect of BWSTT combined with multichannel electrical stimulation in stroke patients and reported improvements of the gait ability, including gait speed, cadence, and stride length. In another study, the combination of BWSTT and FES led to improvements in motor recovery and seemed to have improved the gait pattern of stroke patients.15 Recently, a new FES system (power-assisted FES [PAFES] system) is being used as an approach for improvement of functional ability in stroke patients. PAFES induces greater muscle contraction by an electrical stimulation, which is regulated by the control system in proportion to the integrated electromyography (EMG) signal.16 Proprioceptive sensory feedback has been reported to play an important role in PAFES.17 Hara et al.16 reported that PAFES was effective in reducing the spasticity of the paretic upper extremity in stroke patients. In addition, another study reported that PAFES can effectively improve wrist and finger extension and shoulder flexion.17 Despite the fact that reduced walking ability is one of the major disabilities in stroke patients, investigations of PAFES for improvement of walking ability are insufficient. To the best of the authors’
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knowledge, this is the first report using PAFES for improvement of walking ability in stroke patients. The purpose of this study was to investigate the effect of BWSTT with PAFES (BWT-PAFES) on functional movement and gait in stroke patients. The authors hypothesized that stroke patients would show improvement in functional movement and gait performance after 4 wks of BWT-PAFES.
METHODS Participants Thirty-five stroke patients undergoing standard rehabilitation were recruited on a voluntary basis from the inpatient rehabilitation hospital. The inclusion criteria for this study were categorized as (1) a diagnosis of stroke (cerebral cortex lesion: ischemic brain injury or intracerebral hemorrhage) shown by magnetic resonance imaging or computed tomography, (2) at least 5 degrees of ankle passive range of motion and at least 1 of 5 in ankle dorsiflexion muscle strength (manual muscle test),18 (3) sufficient cognition to follow simple instructions and understand the content and purpose of the study (Korean version of the MiniYMental State Examination score of Q24 points), (4) ability to walk 10 m independently with or without use of an assistive device, (5) absence of a musculoskeletal condition that could potentially affect the ability to walk safely, (6) a Brunnstrom stage between 1 and 4 for the lower extremity, (7) absence of a hearing disorder, and (8) no skin allergy to electric stimulation. The exclusion criteria were (1) excessive spasticity in the affected leg, as defined with a score of 3 or greater on the Modified Ashworth Spasticity Scale; (2) any comorbidity or disability other than those that would preclude gait training; (3) participation in other studies or rehabilitation program; (4) severe heart disease or uncontrolled hypertension and pain; and (5) any neurologic or orthopedic diseases that may interfere with the study. Five of the 35 potential subjects were excluded because they failed to meet the inclusion criteria (uncontrolled hypertension, hearing disorder, and knee pain) or they met the exclusion criteria (participation in other studies). Finally, a total of 30 subjects were included in this study. The subjects were briefed on the experimental procedure, and written consents were collected from all subjects before the experiment. Human subject ethical approval was obtained from the relevant committee in the Sahmyook University institutional review board before conducting the experiment.
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Procedure This study used a randomized pretest and posttest control group design. Pretest and posttest analyses consisted of functional movement and gait ability. After the pretest, all participants were randomized to the BWT-PAFES group (n = 15) or the BWSTT group (n = 15). Randomization was computer generated using a basic random number generator. All subjects participated in a training program for 4 wks after the pretest. In addition, the posttest was conducted 3 days after the end of the intervention period. All measurements were performed while the patients were in the admitted rehabilitation ward, and the assessor was blinded. All subjects participated in the same standard rehabilitation program, which consisted of conventional physical therapy and occupational therapy. Conventional physical therapy, including increased trunk stability (bridge exercise and gym ball exercise), lower extremity muscle strength (standing on the paretic leg and going up and down the stairs),
and gait (gait pattern reeducation and parallel bar gait), was performed for 60 mins per day, five times a wk, for 4 wks. Occupational therapy, an upper extremity training program for activities of daily living (stretching, active-assisted range of motion, and reaching and grasping), was performed for 30 mins per day, five times a week, for 4 wks. In addition, the subjects in the experimental group participated in BWT-PAFES and the subjects in the control group participated in BWSTT. After pretest, training (BWTPAFES and BWSTT) and standard rehabilitation programs provided to the BWT-PAFES and BWSTT groups were conducted in a different therapeutic building. Thus, none of the subjects were aware of which group they were in. In addition, treadmill trainers and therapists (physical and occupational therapy) were unaware of the group allocation. Training sessions of both the experimental and control groups lasted 30 mins with an optional break time (3 mins). All participants successfully completed the study protocol, and the attendance rate was 100%
FIGURE 1 Flow diagram of the study. www.ajpmr.com
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for the 4-wk intervention. The flow chart of the study is shown in Figure 1.
Intervention BWSTT with PAFES PAFES, a portable two-channel neuromuscular stimulator (PAS; OG Giken, Okayama, Japan), was used for delivery of electrical stimulation during BWSTT. The PAFES device induces greater muscle contraction by electrical stimulation in proportion to the integrated EMG signal.16 The PAFES system was composed of a setting and input system and a portable stimulator. The setting and input system and the portable stimulator work together via a Bluetooth system connection, and the surface electrodes were connected to the portable stimulator. The surface electrodes pick up the EMG signals (threshold intensity) as the target muscle starts to contract. The setting and input system evaluates the amount of activity in the target muscle and determines whether the stimulation intensity is proportional to the muscle activity. In other words, the same surface electrodes detect the EMG signals at the target muscle and stimulate them with a stimulus intensity proportional to the integrated EMG signals. However, when there is no voluntary contraction to the target muscle, the PAFES system does not work. Sensitivity of the EMG signal can be set from 1,000 to 10,000 times, and stimulation output had a rectangular-wave biphasic pulse duration of 50 and an adjustable voltage between 0 and 160 V peak to peak. The PAFES has two channels; however, this study used only one channel. According to previous evidence on FES targeting stroke patients, the improvement of swing phase in the gait cycle, when FES was applied to both the dorsiflexor and plantarflexor
muscles, was less than when FES was applied to the dorsiflexor muscle alone.13 On the basis of a previous study, surface electrode was applied to the tibialis anterior muscle (Fig. 2A). Before the start of intervention, the subjects participated in an assessment for the detection of threshold intensity. The PAFES system was set on the basis of the detected threshold intensity. In addition, the trainer checked the settings of the PAFES device once a week and modified the threshold intensity settings for individuals as needed. BWT-PAFES was performed targeting the tibialis anterior muscle of the affected lower limb during BWS treadmill walking but will not work when the target muscle has no muscle contraction (Fig. 2B). The portable stimulator was fixed without shaking using a strap to the thigh. Because the portable stimulator is light, the patients could perform BWT-PAFES without interference. In addition, BWT-PAFES started with 40% BWS condition using a harness (walking harness; LINAK, Nordborg, Denmark).18 The BWS was decreased progressively by a 10% increment a week for the subjects’ muscle activity during BWT-PAFES.19,20 All subjects recorded walking speeds on the treadmill before and after the intervention. The mean treadmill speed for the subjects during the initial testing was 0.4 m/sec, and if the subjects maintained a good gait pattern, the treadmill speed was increased progressively as rapidly as possible. In this study, a good gait pattern indicates an increase in the single-limb support time on the paretic leg. According to a previous study on BWSTT of stroke patients, increment of single-limb support time on the paretic limb can lead to weight support on the paretic side.21 Thus, gait training to improve walking ability in hemiparetic individuals should provide increased single-limb support time on the
FIGURE 2 A, The location of surface electrode. B, Setting for the BWT-PAFES.
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paretic limb.21 All subjects received verbal cues during the intervention to maintain good gait pattern. Instructions, such as trunk alignment, step length, and knee flexion for the swing phase, were given according to the subjects’ abilities. The change for BWS and treadmill speed was applied with the same method in both the BWTPAFES and BWSTT groups. According to the recorded data, the mean treadmill speed was increased by 10% a week. In the final week of training, the mean treadmill speed and BWS was 0.6 m/sec and 10%, respectively. Emergency stop devices were operated for the subjects’ safety during intervention. In addition, a trainer watched the subjects carefully beside the treadmill during an intervention to prevent the subjects from experiencing a fall during training and for identification of any other signs of excessive fatigue.22 The subjects in the experimental group underwent BWT-PAFES for 30 mins per day, five times a week, for 4 wks, and those in the control group underwent BWSTT for 30 mins per day, five times a week, for 4 wks. In BWSTT, the treadmill walking speed, amount of BWS, and verbal cue during treadmill walking were controlled using a method similar to that used in the experimental group. However, PAFES was not applied in the control group.
Measurement Tools Functional Movement Ability. Functional movement was measured using the Berg Balance Scale (BBS), the Timed Up and Go test (TUG), and the Stroke Rehabilitation Assessment of Movement (STREAM). The BBS is a valid and reliable instrument for the measurement of balance ability in elderly or stroke patients. BBS scores range from 0 to 56 points, and higher scores indicate better dynamic balance.23 The TUG is measured as time (seconds) required for performance of the following series of actions: stand up from a chair, walk 3 m at normal walking speed, turn around, walk back, and sit down. Use of assistive devices was permitted when necessary.24 The STREAM is a clinical measurement tool for the evaluation of the recovery of voluntary movement and basic mobility after stroke. The final version of the STREAM measure consists of 30 items or test movements that are equally distributed among the three subscales: 10 items assessing upper limb movements, 10 items assessing lower limb movements, and 10 items for basic mobility. Limb movements are scored on a 3-point scale. Mobility items are scored on a 4point scale similar to that used for scoring limb movements except that a category has been added to www.ajpmr.com
allow for independence with the help of a mobility aid. Thus, the maximum raw total STREAM score is 70, with each of the limb subscales scored out of 20 points and the mobility subscale scored out of 30 points.25 The reliability of the STREAM scores was demonstrated by generalizability correlation coefficients of 0.99 for the total scores and 0.96 to 0.99 for the subscale scores.25 Gait Ability. Gait ability was measured using an electrical walkway system (GAITRite; CIR System Inc, New Jersey). The GAITRite system provided temporal and spatial gait parameters via an electronic walkway connected to the serial port of a personal computer. The standard GAITRite walkway contained six sensor pads encapsulated in a roll-up carpet with an active area of 3.66 m length and 0.61 m width.26 The participants walked across a walkway over the mat under three trials at a selfdetermined comfortable gait speed. A resting period (2 mins) was provided between the measurements to offset any potential fatigue effects. The subjects initiated and terminated walking for a minimum of 3 m from the start to the end of the walkway to maintain gait speed on the mat. A verbal command was given to initiate walking, and one of the examiners accompanied the subjects to prevent them from falling while walking. The subjects were allowed to use assistive devices that were used during testing. All values were averaged for the three trials. The gait parameters recorded were as follows: velocity, cadence, paretic side step length, and stride length.
Data Analysis Statistical analyses were performed using the Statistical Package for the Social Sciences, version 15.0. Descriptive statistics were used to describe patient characteristics. The Shapiro-Wilk test was used to confirm that all outcome variables were normally distributed. Independent t test (for continuous variables), Mann-Whitney U test (for ordinal variables), and W2 test (for categorical variables) were used for comparison of the baseline characteristics of the subjects in both groups. For measures of dependent variables, analysis of variance with mixed design (within-subject factor = time, between subject factor = group) was used to compare each outcome variable between two time points (pretest and posttest). To examine the main effects of the intervention, a two (group) two (time) analysis of variance with repeated measure was performed. A significance level of 0.05 was used in all measurements. Body Weight Support Treadmill with FES
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RESULTS
step length (F = 12.911, P = 0.001), and stride length (F = 14.731, P = 0.001).
Baseline Characteristics General characteristics of the subjects are shown in Table 1. No significant differences in general characteristics and dependent variables were observed between the BWT-PAFES and BTSTT groups.
Changes of Functional Movement and Gait Ability Changes in functional movement and gait ability are shown in Table 2. After 4 wks of intervention, both groups showed a main effect of time on the BBS (F = 135.946, P = 0.000), the TUG (F = 269.769, P = 0.000), the STREAM (F = 340.474, P = 0.000), velocity (F = 152.577, P = 0.000), cadence (F = 119.833, P = 0.000), paretic side step length (F = 84.066, P = 0.000), and stride length (F = 86.492, P = 0.000). In addition, significant differences were observed for the group time interactions of the BBS (F = 11.539, P = 0.002), the TUG (F = 20.431, P = 0.000), the STREAM (F = 10.881, P = 0.003), velocity (F = 20.328, P = 0.000), cadence (F = 15.653, P = 0.000), paretic side
DISCUSSION The current study was conducted to examine the effect of BWT-PAFES on functional movement and gait in stroke patients. After 4 wks of BWT-PAFES, significant improvements in functional movement and gait were observed between the BWT-PAFES and BWSTT groups. In the field of stroke rehabilitation, the effectiveness of treadmill training on functional ability of stroke patients has been demonstrated through previous studies.3,6 In addition, treadmill training for achievement of independent ambulation was used combined with various other approaches.15,27 Treadmill training may have the greatest impact when applied before overground gait training; in particular, it has been identified that the training effect was maximized when combined with other interventions.28 Trueblood27 reported that treadmill training with BWS induced normalization of the gait pattern and postural control in patients with chronic
TABLE 1 Homogeneity test for general characteristics and dependent variables of the subjects (N = 30)
General characteristics Sex Male/female Paretic side Left/right Etiology Infarction/hemorrhage Ankle dorsiflexor,a grade MAS (1/1+/2) Brunnstrom stages (2/3/4) Age, yrs Height, cm Weight, kg Stroke onset duration,b mos MMSE-K, score Dependent variables BBS, score TUG, secs STREAM, score Velocity, cm/sec Cadence, steps per minute P-step length, cm P-stride length, cm
BWT-PAFES (n = 15)
BWSTT (n = 15)
P
12/3
10/5
0.426d
7/8
8/7
0.726d
10/5 2 (1~2)c 5/9/1 5/7/3 52.47 T 9.41 169.26 T 7.92 65.67 T 10.28 4.0 T 0.41 26.53 T 1.96
12/3 2 (1~2)c 4/9/2 3/9/3 56.73 T 7.24 164.21 T 9.35 65.47 T 13.24 4.07 T 1.03 27.07 T 1.98
0.426d 0.539e V V 0.175f 0.122f 0.965f 0.868f 0.465f
34.13 T 3.81 24.36 T 3.85 45.00 T 8.06 35.93 T 20.08 61.97 T 21.02 32.29 T 9.18 62.27 T 19.45
34.27 T 27.30 T 43.40 T 38.08 T 66.55 T 34.49 T 61.29 T
2.66 5.73 7.38 19.64 20.14 10.67 15.98
0.912f 0.110f 0.575f 0.769f 0.547f 0.550f 0.881f
Values are expressed as number or mean T standard deviation. a Measured by manual muscle test. b Durations between stroke onset and pretest. c Median (range). d 2 W test. e Mann-Whitney U test. f Independent t test. MAS, Modified Ashworth Scale; MMSE-K, Korean version of the MiniYMental State Examination; P, paretic side.
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62.27 T 19.45 61.29 T 15.98 92.84 T 18.68 73.10 T 21.71 30.57 T 16.44a,b 12.71 T 7.39a 86.492 (0.000) 14.731 (0.001) T 9.18 T 10.67 T 9.34 T 11.41 T 7.82a,b T 8.77a (0.000) (0.001) 32.29 34.49 51.64 42.94 19.36 8.46 84.066 12.911 61.97 T 21.02 66.55 T 20.14 92.13 T 21.63 84.30 T 23.45 30.15 T 12.43a,b 17.75 T 13.16a 119.833 (0.000) 15.653 (0.000)
Values are expressed as mean T standard deviation. a Significant differences between pretest and posttest, P G 0.05. b Significant differences between the BWT-PAFES group and the BWSTT group, P G 0.05. P, paretic side.
35.93 T 20.08 38.08 T 19.64 76.00 T 19.96 56.72 T 28.81 40.07 T 11.55a,b 18.64 T 14.33a 152.577 (0.000) 20.328 (0.000) 24.36 T 3.85 27.30 T 5.73 15.10 T 3.40 22.04 T 4.79 j9.25 T 2.19a,b j5.25 T 2.63a 269.769 (0.000) 20.431 (0.000) Pretest
BWT-PAFES (n = 15) BWSTT (n = 15) Posttest BWT-PAFES (n = 15) BWSTT (n = 15) Change BWT-PAFES (n = 15) BWSTT (n = 15) F (P) for time factor F (P) for group time interaction
34.13 T 3.81 34.27 T 2.66 45.07 T 3.01 40.27 T 3.60 10.93 T 4.74a,b 6.00 T 3.02a 135.946 (0.000) 11.539 (0.002)
45.00 T 8.06 43.40 T 7.38 59.07 T 6.89 53.20 T 7.55 14.07 T 4.01a,b 9.80 T 3.00a 340.474 (0.000) 10.881 (0.003)
P-Stride Length, cm P-Step Length, cm Cadence, Steps per Minute TUG, secs Test
Group
BBS (Score)
STREAM (Score)
Velocity, cm/sec
Gait Ability Functional Movement
TABLE 2 Comparison of balance, functional movement, and gait ability within groups and between groups (N = 30)
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stroke. Hesse et al.4 reported that the combination of conventional physical therapy and BWSTT was more effective in improving gait ability than was physical therapy only. Previous studies on treadmill training combined with other interventions demonstrated that the repetitive gait pattern generated by treadmill walking induced motor recovery and brain reorganization, and it led to the improvement of functional activity.7,27 In addition, the combination of BWSTT and FES was attempted in stroke rehabilitation. FES can assist in the swing phase of the gait cycle during treadmill walking using electrical currents to activate the nerves innervating paretic lower extremity resulting from stroke.29 BWSTT combined with FES was more comfortable because the placement of the foot during early stance was easier and decreased the participation of the assistant during training.15 Many previous studies have demonstrated positive effects of a combination of BWSTT and FES on walking ability of stroke patients14,15; however, a recent study30 reported that the addition of FES to the BWSTT did not provide any additional benefits in motor function and walking ability. Although FES has been used for improvement of walking ability,29 preprogrammed stimulation of FES induced only cyclic muscle contractions without active participation of the subject.31 Of particular interest, a previous study reported that active participation in motor training is more effective than passive participation in improving functional activity.22 Currently, there is a growing interest in PAFES. PAFES provides stimulation when voluntarily generated EMG signals surpass a preset threshold.16 PAFES has shown a positive effect in paralyzed arm movement and function in stroke patients.16,17 However, efficacy of PAFES for walking remains unknown. Thus, the authors attempted a combination of BWSTT and PAFES used for improvement of walking ability. In this study, greater significant improvements in functional movement were observed in the BWT-PAFES group compared with the BWSTT group. Motor relearning is defined as the reacquisition of motor skills after injury of the central nervous system, and it is known to be facilitated when active repetitive movement was applied.32 Makowski et al.33 reported that FES combined with voluntary effort may have the potential to increase functional movement, and Boyaci et al.31 reported that EMGtriggered stimulation increased the upper limb motor function and functional recovery of stroke patients. The finding from the current study is consistent with that Body Weight Support Treadmill with FES
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from previous studies; the authors believe that the facilitation of motor relearning caused by voluntary movement in PAFES led to an improvement of functional movement of stroke patients. Another finding of the present study is the significant improvement observed in gait ability in the BWT-PAFES group compared with the BWSTT group. A possible reason for the improvement of gait ability between the groups may be the increased somatosensory input and facilitation of neuroplasticity caused by application of PAFES to the ankle dorsiflexor. Embrey et al.34 reported that an electrical stimulation of the dorsiflexor during the swing phase in gait cycle induced normal gait and the achievement of better outcomes of stroke patients. The basic role of PAFES is to assist in the activation of impaired efferent pathways.35 It is based on the sensory-motor integration theory36 that sensory input from movement of an affected limb directly influences the subsequent motor output. In other words, because impairment of the somatosensory input may be the cause of delayed motor recovery in stroke patients, accurate somatosensory input is essential for the achievement of motor recovery.37 According to previous evidence, activation of impaired efferent pathways is maximized when it occurs with active movement.22,31 In addition, increased somatosensory input during walking could provide improvement of gait patterns in stroke patients.38 Thus, it is assumed that an addition of PAFES to BWSTT could lead to an increased somatosensory input by active participation of the ankle dorsiflexor during the BWSTT, thereby leading to an improvement of gait ability. As another possible explanation for the current findings, previous studies on functional magnetic resonance imaging reported that active participation of an active stimulation method exerts a positive effect on neuroplasticity.39,40 However, because functional magnetic resonance imaging was not included as a dependent variable in this study, accurate comparison is difficult. Thus, more research is required to investigate the effect of PAFES on neuroplasticity. The findings of the current study demonstrated a beneficial effect of PAFES applied to the ankle dorsiflexor during BWSTT on functional movement and gait ability in stroke patients; however, it had some limitations. First, a statistical power was not calculated and a small number of subjects were recruited. Therefore, these results cannot be generalized to all stroke patients. Second, long-term follow-up of BWT-PAFES was not considered. Therefore, the authors suggest that further studies
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include long-term follow-up to examine the longterm effect of BWT-PAFES.
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Body Weight Support Treadmill with FES Copyright © 2013 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
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