Karen J. Nolan

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

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.

The Effects of Peroneal Nerve Functional Electrical Stimulation Versus Ankle-Foot Orthosis in Patients With Chronic Stroke A Randomized Controlled Trial

Background. Evidence supports peroneal nerve functional electrical stimulation (FES) as an effective alternative to ankle-foot orthoses (AFO) for treatment of foot drop poststroke, but few randomized controlled comparisons exist. Objective. To compare changes in gait and quality of life (QoL) between FES and an AFO in individuals with foot drop poststroke. Methods. In a multicenter randomized controlled trial (ClinicalTrials.gov #NCT01087957) with unblinded outcome assessments, 495 Medicare-eligible individuals at least 6 months poststroke wore FES or an AFO for 6 months. Primary endpoints: 10-Meter Walk Test (10MWT), a composite of the Mobility, Activities of Daily Living/Instrumental Activities of Daily Living, and Social Participation subscores on the Stroke Impact Scale (SIS), and device-related serious adverse event rate. Secondary endpoints: 6-Minute Walk Test, GaitRite Functional Ambulation Profile (FAP), Modified Emory Functional Ambulation Profile (mEFAP), Berg Balance Scale (BBS), Timed Up and Go, individual SIS domains, and Stroke-Specific Quality of Life measures. Multiply imputed intention-to-treat analyses were used with primary endpoints tested for noninferiority and secondary endpoints tested for superiority. Results. A total of 399 subjects completed the study. FES proved noninferior to the AFO for all primary endpoints. Both the FES and AFO groups improved significantly on the 10MWT. Within the FES group, significant improvements were found for SIS composite score, total mFEAP score, individual Floor and Obstacle course time scores of the mEFAP, FAP, and BBS, but again, no between-group differences were found. Conclusions. Use of FES is equivalent to the AFO. Further studies should examine whether FES enables better performance in tasks involving functional mobility, activities of daily living, and balance.

Preservation of the first rocker is related to increases in gait speed in individuals with hemiplegia and AFO

BACKGROUND Changes in impulse during the first rocker (braking force) and third rocker (propulsion force) may affect changes in gait speed after orthotic intervention. The purpose of this investigation was to objectively measure changes in impulse during double support and correlate those findings to changes in gait speed with and without ankle foot orthosis in individuals with hemiplegia. METHODS Fifteen adults with stroke-related hemiplegia walked with and without ankle foot orthosis while foot pressure data was collected bilaterally. Outcome measures included: gait cycle time (s), mean force (N), and impulse (Ns) in the wholefoot, hindfoot, forefoot, and toe box during initial double support and terminal double support. FINDINGS Time significantly decreased during the entire gait cycle, initial double support, and terminal double support, with the ankle foot orthosis. During initial double support, affected limb impulse significantly decreased with the ankle foot orthosis in the wholefoot (P=0.016), and hindfoot (P=0.006), and hindfoot impulse % change and gait speed % change were significantly correlated (P=0.007). During terminal double support, affected limb impulse was not significantly different in the wholefoot or forefoot and these changes were not significantly correlated to gait speed. INTERPRETATION Previous research found that orthotics increase gait speed in individuals with hemiplegia. This research suggests that the increase in speed is not due to increased propulsive forces at the end of terminal double support, but due to decreased braking forces during initial double support. Therefore, the orthosis preserved the first ankle rocker and provided a more efficient weight acceptance which positively affected gait speed.

Long-Term Follow-up to a Randomized Controlled Trial Comparing Peroneal Nerve Functional Electrical Stimulation to an Ankle Foot Orthosis for Patients With Chronic Stroke:

Background. Evidence supports peroneal nerve functional electrical stimulation (FES) as an effective alternative to ankle foot orthoses (AFO) for treatment of foot drop poststroke, but few long-term, randomized controlled comparisons exist. Objective. Compare changes in gait quality and function between FES and AFOs in individuals with foot drop poststroke over a 12-month period. Methods. Follow-up analysis of an unblinded randomized controlled trial (ClinicalTrials.gov #NCT01087957) conducted at 30 rehabilitation centers comparing FES to AFOs over 6 months. Subjects continued to wear their randomized device for another 6 months to final 12-month assessments. Subjects used study devices for all home and community ambulation. Multiply imputed intention-to-treat analyses were utilized; primary endpoints were tested for noninferiority and secondary endpoints for superiority. Primary endpoints: 10 Meter Walk Test (10MWT) and device-related serious adverse event rate. Secondary endpoints: 6-Minute Walk Test (6MWT), GaitRite Functional Ambulation Profile, and Modified Emory Functional Ambulation Profile (mEFAP). Results. A total of 495 subjects were randomized, and 384 completed the 12-month follow-up. FES proved noninferior to AFOs for all primary endpoints. Both FES and AFO groups showed statistically and clinically significant improvement for 10MWT compared with initial measurement. No statistically significant between-group differences were found for primary or secondary endpoints. The FES group demonstrated statistically significant improvements for 6MWT and mEFAP Stair-time subscore. Conclusions. At 12 months, both FES and AFOs continue to demonstrate equivalent gains in gait speed. Results suggest that long-term FES use may lead to additional improvements in walking endurance and functional ambulation; further research is needed to confirm these findings.

Objective Assessment of Functional Ambulation in Adults with Hemiplegia using Ankle Foot Orthotics after Stroke

To objectively evaluate the effect of ankle foot orthotics (AFOs) on functional ambulation in individuals with hemiplegia secondary to stroke using quantifiable outcome measures.

Evaluation of a dynamic ankle foot orthosis in hemiplegic gait: A case report

This investigation utilized a single case design to evaluate the effects of a dynamic AFO on ambulation in post stroke hemiplegia. A single patient with stroke related hemiplegia using a dynamic AFO underwent gait analysis while walking on level ground. Outcome measures included temporal-spatial gait parameters and bilateral kinematic joint angles at the ankle, knee, and hip with and without AFO. Walking speed, stride length, step length and cadence increased with the dynamic AFO. Step width and double support decreased, while single support remained unchanged on the affected limb with the dynamic AFO. With the dynamic AFO there was increased hip flexion at foot strike and toe-off, increased hip sagittal plane angular velocity during swing, and decreased abduction. The dynamic AFO had a positive effect on the participants overall gait which included improved temporal-spatial parameters and gait velocity which is likely due to a decrease in the overall energy cost of walking. Kinematic angles at the hip were most notably affected by brace utilization and this effect should be more fully explored. Further research with a larger sample utilizing dynamic AFOs is indicated to explore the generalizability of these findings and to determine the potential utility of these braces as an alternative to the traditionally prescribed solid AFO.

Weight transfer analysis in adults with hemiplegia using ankle foot orthosis

Background: Identifying and understanding the changes in transfer of momentum that are directly affected by orthotic intervention are significant factors related to the improvement of mobility in individuals with hemiplegia. Objectives: The purpose of this investigation was to use a novel analysis technique to objectively measure weight transfer during double support (DS) in healthy individuals and individuals with hemiplegia secondary to stroke with and without an ankle foot orthosis. Study design: Prospective, Repeated measures, case-controlled trial. Methods: Participants included 25 adults with stroke-related hemiplegia >6 months using a prescribed ankle foot orthosis and 12 age-matched healthy controls. Main outcome measures included the weight transfer point timing (WTP, %DS), maximum total force timing (MTF, %DS), timing difference between WTP and MTF (MTF-WTP, %DS) and the linearity of loading (LOL, R2) during the DS phase of the gait cycle. Results: The WTP and LOL were significantly different between conditions with and without the ankle foot orthosis for the affected and unaffected limb in post-stroke individuals, p ≤ 0.01. The MTF and difference in timing between MTF-WTP were significantly different during affected limb loading with and without the ankle foot orthosis in the stroke group, p ≤ 0.0001 and p = 0.03, respectively. MTF, MTF-WTP and LOL were significantly different between individuals with stroke (during affected limb loading) and healthy controls (during right limb loading). Conclusions: This research established a systematic method for analysing weight transfer during walking to evaluate the effect of an ankle foot orthosis on loading during double support in hemiplegic gait. This novel method can be used to elucidate biomechanical mechanisms behind orthosis-mediated changes in gait patterns and quantify functional mobility outcomes in rehabilitation. Clinical relevance This novel approach to orthotic assessment will provide the clinician with needed objective evidence to select the most effective orthotic intervention to maximize functional recovery for individuals with hemiplegia secondary to stroke.

EMG of the tibialis anterior demonstrates a training effect after utilization of a foot drop stimulator

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.

Changes in center of pressure displacement with the use of a foot drop stimulator in individuals with stroke.

BACKGROUND 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. METHODS 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. FINDINGS 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. INTERPRETATION 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.

Evaluation of a Robotic Exoskeleton for Gait Training in Acute Stroke: A Case Study

The application of robotic exoskeletons in gait therapy during stroke rehabilitation has grown rapidly over the past decade. The purpose of this investigation is to determine the impact of a robotic exoskeleton (RE) on temporal spatial gait parameters as compared to traditional standard of care gait training in a single inpatient after acute stroke. Outcome measures included temporal spatial gait parameters while walking with and without an RE during a single gait training session two weeks post stroke. During gait training in the RE, walking speed, and stride length increased while step width decreased on the affected and unaffected side. Total double support time decreased, and single support and swing time increased on the affected and unaffected limb during gait training in the RE. Gait training in the RE had a positive effect on the patients overall gait which included improved temporal spatial parameters and gait speed. Positive changes in temporal spatial parameters were evident on the affected and unaffected limb. Preliminary rehabilitative improvements with the RE device may include a gait training environment that is more symmetrical and may improve weight transfer and overall gait speed. Further research with a larger sample with various level of impairment utilizing an RE for gait training is needed to determine the potential utility of REs as an alternative to traditional gait training.