Effect of a Foot-Drop Stimulator and Ankle-Foot Orthosis on Walking Performance After Stroke: A Multicenter Randomized Controlled Trial

1University of Alberta, Edmonton, Alberta, Canada.
Neurorehabilitation and neural repair (Impact Factor: 3.98). 04/2013; 27(7). DOI: 10.1177/1545968313481278
Source: PubMed


BACKGROUND: . Studies have demonstrated the efficacy of functional electrical stimulation in the management of foot drop after stroke. OBJECTIVE: . To compare changes in walking performance with the WalkAide (WA) foot-drop stimulator and a conventional ankle-foot orthosis (AFO). METHODS: . Individuals with stroke within the previous 12 months and residual foot drop were enrolled in a multicenter, randomized controlled, crossover trial. Subjects were assigned to 1 of 3 parallel arms for 12 weeks (6 weeks/device): arm 1 (WA-AFO), n = 38; arm 2 (AFO-WA), n = 31; arm 3 (AFO-AFO), n = 24. Primary outcomes were walking speed and Physiological Cost Index for the Figure-of-8 walking test. Secondary measures included 10-m walking speed and perceived safety during this test, general mobility, and device preference for arms 1 and 2 for continued use. Walking tests were performed with (On) and without a device (Off) at 0, 3, 6, 9, and 12 weeks. RESULTS: . Both WA and AFO had significant orthotic (On-Off difference), therapeutic (change over time when Off), and combined (change over time On vs baseline Off) effects on walking speed. An AFO also had a significant orthotic effect on Physiological Cost Index. The WA had a higher, but not significantly different therapeutic effect on speed than an AFO, whereas an AFO had a greater orthotic effect than the WA (significant at 12 weeks). Combined effects on speed after 6 weeks did not differ between devices. Users felt as safe with the WA as with an AFO, but significantly more users preferred the WA. CONCLUSIONS: . Both devices produce equivalent functional gains.

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    • "Previous research evaluating the immediate orthotic effect has shown only small changes in walking speed, improved dorsiflexion angle, and improved temporal–spatial characteristics (Knutson and Chae, 2010; Kottink et al., 2007; Sabut et al., 2010; Taylor et al., 1999a,b). These results demonstrate the efficacy for FDS utilization in poststroke rehabilitation but they fail to precisely indicate how FDS technology can improve gait mechanisms by helping to restore or maintain function (Everaert et al., 2013; Stein et al., 2010). "
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    ABSTRACT: Center of pressure measured during gait can provide information about underlying control mechanisms and the efficacy of a foot drop stimulator. This investigation evaluated changes in center of pressure displacement in individuals with stroke with and without a foot drop stimulator. Individuals with stroke-related foot drop (n=11) using a foot drop stimulator and healthy controls (n=11). Walking speed and bilateral center of pressure variables: 1) net displacement; 2) position and maximum displacement; and 3) mean velocity during walking. On the affected limb with the foot drop stimulator as compared to the affected limb without the foot drop stimulator: 1) increased anterior/posterior maximum center of pressure excursion 8% during stance; 2) center of pressure at initial contact was 6% more posterior; 3) medial/lateral mean, maximum and minimum center of pressure position during stance all significantly decreased; 4) anterior/posterior net displacement increased during stance and single support; and 5) anterior/posterior velocity of the center of pressure increased during stance. Individuals with stroke using a foot drop stimulator contacted the ground more posterior at initial contact and utilized more of the anterior/posterior plantar surface of the foot on the affected limb during stance. With the foot drop stimulator there was a shift in center of pressure toward the medial side possibly indicating an improvement in equinovarus gait where there is a tendency to load the lateral foot throughout stance. For individuals with stroke a foot drop stimulator can improve displacement of the center of pressure which indicates improved forward progression and stability during walking. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Clinical biomechanics (Bristol, Avon) 03/2015; 30(7). DOI:10.1016/j.clinbiomech.2015.03.016 · 1.97 Impact Factor
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    • "Research investigating FES in individuals with acute and chronic hemiplegia and FD secondary to stroke indicate that this technology has the potential to restore physiological function and improve community ambulation (Robbins, Houghton, Woodbury, & Brown, 2006; Sabut, Sikdar, Mondal, Kumar, & Mahadevappa, 2010). These results demonstrate the efficacy for FDS utilization in post stroke rehabilitation but they fail to precisely indicate how FDS technology can restore motor function (Everaert et al., 2013; Kesar et al., 2010; Kesar et al., 2009, 2011; Kottink et al., 2004; Stein et al., 2006, 2010; Taylor et al., 1999). "
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    ABSTRACT: BACKGROUND: Functional Electrical Stimulation (FES) applied through a foot drop stimulator (FDS) is a rehabilitation intervention that can stimulate the common peroneal nerve to provide dorsiflexion at the correct timing during gait. OBJECTIVE: To determine if FES applied to the peroneal nerve during walking through a FDS would effectively retrain the electromyographic temporal activation of the tibialis anterior in individuals with stroke. METHODS: Surface electromyography (EMG) were collected bilaterally from the tibialis anterior (TA) while participants (n = 4) walked with and without the FDS at baseline and 4 weeks. Comparisons were made between stimulation timing and EMG activation timing to produce a burst duration similarity index (BDSI). RESULTS: At baseline, participants displayed variable temporal activation of the TA. At 4 weeks, TA activation during walking without the FDS more closely resembled the pre-programmed FDS timing demonstrated by an increase in BDSI scores in all participants (P = 0.05). CONCLUSIONS: Continuous use of FDS during a task specific movement can re-train the neuromuscular system. After 4 weeks of utilization the FDS trained the TA to replicate the programmed temporal activation patterns. These findings begin to establish the FDS as a rehabilitation intervention that may facilitate recovery rather than just compensate for stroke related gait impairments due to foot drop.
    Neurorehabilitation 07/2014; 35(2). DOI:10.3233/NRE-141126 · 1.12 Impact Factor
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    ABSTRACT: At the present time, there is only one standard test that evaluates the performance of transcutaneous electrical nerve stimulator (TENS) devices. The rationale for this test is not well documented and its scope and limitations are unclear. The thrust of this paper is to discuss the selected factors that are likely to affect the performance standard. These include stimulus waveform, constant current versus constant current voltage output and electrode size. Each of these parameters have been shown to influence the stimulation output and the conductive characteristics of human tissue. Stimulating with different waveforms significantly affects peak current, peak voltage and total pulse charge, but insignificantly affects the phase charge. Using a different electrode size alter all stimulus output values during excitation of peripheral nerves, indicating tile need to specify electrode size for simulated tissue loads. Data show that a single load is not adequate to simulate the conductive medium of human tissue. Instead a family of loads is considered and their validation for testing conditions is discussed
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