A Clinical Practice Guideline for the Use of Ankle-Foot Orthoses and Functional Electrical Stimulation Post-Stroke.

BACKGROUND: Level of ambulation following stroke is a long-term predictor of participation and disability. Decreased lower extremity motor control can impact ambulation and overall mobility. The purpose of this clinical practice guideline (CPG) is to provide evidence to guide clinical decision-making for the use of either ankle-foot orthosis (AFO) or functional electrical stimulation (FES) as an intervention to improve body function and structure, activity, and participation as defined by the International Classification of Functioning, Disability and Health (ICF) for individuals with poststroke hemiplegia with decreased lower extremity motor control. METHODS: A review of literature published through November 2019 was performed across 7 databases for all studies involving stroke and AFO or FES. Data extracted included time post-stroke, participant characteristics, device types, outcomes assessed, and intervention parameters. Outcomes were examined upon initial application and after training. Recommendations were determined on the basis of the strength of the evidence and the potential benefits, harm, risks, or costs of providing AFO or FES. RESULTS/DISCUSSION: One-hundred twenty-two meta-analyses, systematic reviews, randomized controlled trials, and cohort studies were included. Strong evidence exists that AFO and FES can each increase gait speed, mobility, and dynamic balance. Moderate evidence exists that AFO and FES increase quality of life, walking endurance, and muscle activation, and weak evidence exists for improving gait kinematics. AFO or FES should not be used to decrease plantarflexor spasticity. Studies that directly compare AFO and FES do not indicate overall superiority of one over the other. But evidence suggests that AFO may lead to more compensatory effects while FES may lead to more therapeutic effects. Due to the potential for gains at any phase post-stroke, the most appropriate device for an individual may change, and reassessments should be completed to ensure the device is meeting the individual's needs. LIMITATIONS: This CPG cannot address the effects of one type of AFO over another for the majority of outcomes, as studies used a variety of AFO types and rarely differentiated effects. The recommendations also do not address the severity of hemiparesis, and most studies included participants with varied baseline ambulation ability. SUMMARY: This CPG suggests that AFO and FES both lead to improvements post-stroke. Future studies should examine timing of provision, device types, intervention duration and delivery, longer term follow-up, responders versus nonresponders, and individuals with greater impairments. DISCLAIMER: These recommendations are intended as a guide for clinicians to optimize rehabilitation outcomes for people with poststroke hemiplegia who have decreased lower extremity motor control that impacts ambulation and overall mobility.A Video Abstract is available as supplemental digital content from the authors (available at: http://links.lww.com/JNPT/A335).

Risk Factors for Stress Fractures in Female Runners: Results of a Survey.

BACKGROUND: Few studies compare women with and without stress fractures and most focus on younger, elite runners. HYPOTHESIS/PURPOSE: Compare risk factors between female runners with and without a stress fracture history. STUDY DESIGN: Case control. METHODS: An online survey targeting women age ≥18 years was distributed primarily via social media. Questions included demographics, running details, cross training, nutrition, injury history, medical/menstrual history, and medications. Women with stress fracture histories answered questions about location, number, and changes made. Data were compared between groups using t-tests, chi-square tests, or Fisher's exact tests. Multivariable logistic regression models simultaneously investigated associations of multiple factors using backward variable selection. RESULTS: Data from 1648 respondents were analyzed. Mean age was 40 years, and 25.4% reported stress fractures. Significant differences were found between groups for days/week running, mileage/week, running pace, years running, having a coach, cycling or swimming, calorie consumption for activity, other running injuries, medical history, medication/supplement intake, age at menarche, and going ≥6 months without a menstrual period. Odds of having a stress fracture were increased with osteopenia (OR 4.14), shin splints (OR 3.24), tendon injuries (OR 1.49), running >20 miles/week (OR 1.74-1.77) compared to 11-20 miles/week, having a coach (OR 1.86), and cycling (OR 1.15). Women running 11:00-11:59 minutes/mile or slower were less likely to have a stress fracture compared to those running 9:00-9:59 minutes/mile (OR 0.43-0.54). The odds of having a stress fracture were 1.43 times higher for going ≥ 6 months without a menstrual period. Use of calcium, probiotics, and vitamin D increased odds. Post fracture, common changes made were with cross training (49%), mileage (49%), and strength training (35%). CONCLUSIONS: Multiple intrinsic and extrinsic factors were identified for female runners who sustained one or more stress fracture during running. Prospective studies are warranted to infer a cause and effect relationship amongst these variables and stress fracture risk. LEVEL OF EVIDENCE: Level IV.

Musculoskeletal Effects of 2 Functional Electrical Stimulation Cycling Paradigms Conducted at Different Cadences for People With Spinal Cord Injury: A Pilot Study.

OBJECTIVE: To compare the musculoskeletal effects of low cadence cycling with functional electrical stimulation (FES) with high cadence FES cycling for people with spinal cord injury (SCI). DESIGN: Randomized pre-post design. SETTING: Outpatient rehabilitation clinic. PARTICIPANTS: Participants (N=17; 14 men, 3 women; age range, 22-67y) with C4-T6 motor complete chronic SCI were randomized to low cadence cycling (n=9) or high cadence cycling (n=8). INTERVENTIONS: Low cadence cycling at 20 revolutions per minute (RPM) and high cadence cycling at 50 RPM 3 times per week for 6 months. Cycling torque (resistance per pedal rotation) increased if targeted cycling cadence was maintained. MAIN OUTCOME MEASURES: Dual-energy x-ray absorptiometry was used to assess distal femur areal bone mineral density, magnetic resonance imaging was used to assess to assess trabecular bone microarchitecture and cortical bone macroarchitecture and thigh muscle volume, and biochemical markers were used to assess bone turnover. It was hypothesized that subjects using low cadence cycling would cycle with greater torque and therefore show greater musculoskeletal improvements than subjects using high cadence cycling. RESULTS: A total of 15 participants completed the study. Low cadence cycling obtained a maximal average torque of 2.9±2.8Nm, and high cadence cycling obtained a maximal average torque of 0.8±0.2Nm. Low cadence cycling showed greater decreases in bone-specific alkaline phosphatase, indicating less bone formation (15.5% decrease for low cadence cycling, 10.7% increase for high cadence cycling). N-telopeptide decreased 34% following low cadence cycling, indicating decreased resorption. Both groups increased muscle volume (low cadence cycling by 19%, high cadence cycling by 10%). Low cadence cycling resulted in a nonsignificant 7% increase in apparent trabecular number (P=.08) and 6% decrease in apparent trabecular separation (P=.08) in the distal femur, whereas high cadence cycling resulted in a nonsignificant (P>.3) 2% decrease and 3% increase, respectively. CONCLUSIONS: This study suggests that the greater torque achieved with low cadence cycling may result in improved bone health because of decreased bone turnover and improved trabecular bone microarchitecture. Longer-term outcome studies are warranted to identify the effect on fracture risk.

Cycling with Functional Electrical Stimulation Before and After a Distal Femur Fracture in a Man with Paraplegia.

CASE PRESENTATION: A man with chronic paraplegia sustained a distal femur fracture following an unrelated fall while enrolled in a study examining musculoskeletal changes after 6 months of cycling with functional electrical stimulation (FES). After healing, he restarted and completed the study. MANAGEMENT AND OUTCOME: Study measures included areal bone mineral density, trabecular bone microarchitecture, cortical bone macroarchitecture, serum bone formation/resorption markers, and muscle volume. The patient made small gains in bone- and muscle-related measures. Bone markers had not returned to baseline prior to restarting cycling, which may have impacted results. DISCUSSION: This case shows that cycling with FES may be safely resumed after distal femur fracture.

Muscle changes following cycling and/or electrical stimulation in pediatric spinal cord injury.

OBJECTIVE: To determine the effect of cycling, electrical stimulation, or both, on thigh muscle volume and stimulated muscle strength in children with spinal cord injury (SCI). DESIGN: Randomized controlled trial. SETTING: Children's hospital specializing in pediatric SCI. PARTICIPANTS: Children (N=30; ages, 5-13y) with chronic SCI. INTERVENTIONS: Children were randomly assigned to 1 of 3 interventions: functional electrical stimulation cycling (FESC), passive cycling (PC), and noncycling, electrically stimulated exercise (ES). Each group exercised for 1 hour, 3 times per week for 6 months at home. MAIN OUTCOME MEASURES: Preintervention and postintervention, children underwent magnetic resonance imaging to assess muscle volume, and electrically stimulated isometric muscle strength testing with the use of a computerized dynamometer. Data were analyzed via analyses of covariance (ANCOVA) with baseline measures as covariates. Within-group changes were assessed via paired t tests. RESULTS: All 30 children completed the training. Muscle volume data were complete for 24 children (8 FESC, 8 PC, 8 ES) and stimulated strength data for 27 children (9 per group). Per ANCOVA, there were differences between groups (P<.05) for quadriceps muscle volume and stimulated strength, with the ES group having greater changes in volume and the FESC group having greater changes in strength. Within-group analyses showed increased quadriceps volume and strength for the FESC group and increased quadriceps volume for the ES group. CONCLUSIONS: Children receiving either electrically stimulated exercise experienced changes in muscle size, stimulated strength, or both. These changes may decrease their risk of cardiovascular disease, insulin resistance, glucose intolerance, and type 2 diabetes. CLINICAL TRIALS REGISTRATION NUMBER: NCT00245726.

Cycling with functional electrical stimulation in an adult with spastic diplegic cerebral palsy.

BACKGROUND AND PURPOSE: Adults with cerebral palsy (CP) are at risk for decreased mobility and health complications, and exercise may combat some of these negative changes. Because people with CP have difficulty generating sufficient muscle force, exercise augmented with functional electrical stimulation (FES) is an option for increasing exercise intensity. This mixed-method (quantitative-qualitative) case report describes the effects-across the International Classification of Functioning, Disability and Health (ICF) model-of cycling with FES (FES cycling) in an adult with CP. CASE DESCRIPTION: An ambulatory 49-year-old man with spastic diplegic CP cycled with FES at home for 30 minutes, 3 times per week, for 12 weeks. Volitional efforts were augmented by FES of the bilateral quadriceps, gastrocnemius, and gluteal muscles. Testing was performed before and after the intervention and 4 weeks after intervention withdrawal. OUTCOMES: After training, quadriceps muscle strength (force-generating capacity) improved by 22.2%, hamstring muscle strength improved by 18.5%, and the Timed "Up & Go" Test time decreased from 11.9 to 9.0 seconds. The patient reported increased performance and satisfaction for self-identified goals at the ICF level of participation, and his score on the Medical Outcomes Study 36-Item Health Survey questionnaire increased from 62.1 to 77.6. However, he reported increased back pain, which he attributed to positioning while cycling. Qualitative interviews provided context (the patient's perspective) for some of the quantitative results. DISCUSSION: The patient made gains in body structure and function, activity, and participation (ICF levels) after FES cycling. The mixed-method approach provided insight into his experiences and perceptions about the measures assessed quantitatively. Further investigation on FES cycling in this population as well as positioning during cycling is warranted.

A randomized controlled trial on the effects of cycling with and without electrical stimulation on cardiorespiratory and vascular health in children with spinal cord injury.

OBJECTIVE: To examine the cardiorespiratory/vascular effects of cycling with and without functional electrical stimulation (FES) in children with spinal cord injury (SCI). DESIGN: Randomized controlled trial. SETTING: Pediatric referral hospital. PARTICIPANTS: Children with SCI (N=30), ages 5 to 13 years, with injury levels from C4 to T11, and American Spinal Injury Association grades A, B, or C. INTERVENTIONS: Children were randomly assigned to 1 of 3 groups: FES leg cycling exercise, passive leg cycling, or noncycling control group receiving electrical stimulation therapy. After receiving instruction on the use of the equipment, children exercised for 1 hour 3 times per week for 6 months at home with parental supervision. MAIN OUTCOME MEASURES: Oxygen uptake (Vo(2)) during an incremental arm ergometry test, resting heart rate, forced vital capacity, and a fasting lipid profile. RESULTS: There were no differences (P>.05) between groups after 6 months of exercise when comparing pre- and postvalues. However, there were differences between groups for some variables when examining percent change. The FES cycling group showed an improvement (P=.035) in Vo(2) (16.2%+/-25.0%) as compared with the passive cycling group (-28.7%+/-29.1%). For lipid levels, the electrical stimulation-only group showed declines (P=.032) in cholesterol levels (-17.1%+/-8.5%) as compared with the FES cycling group (4.4%+/-20.4%). CONCLUSIONS: Cycling with FES led to gains in Vo(2), whereas electrical stimulation alone led to improvements in cholesterol.

Outcomes of a home cycling program using functional electrical stimulation or passive motion for children with spinal cord injury: a case series.

BACKGROUND/OBJECTIVE: Children with spinal cord injury (SCI) are at risk for musculoskeletal and cardiovascular complications. Stationary cycling using functional electrical stimulation (FES) or passive motion has been suggested to address these complications. The purpose of this case series is to report the outcomes of a 6-month at-home cycling program for 4 children with SCI. METHODS: Two children cycled with FES and 2 cycled passively at home for 1 hour, 3 times per week. OUTCOME MEASURES: Data collected included bone mineral density of the left femoral neck, distal femur, and proximal tibia; quadriceps and hamstring muscle volume; stimulated quadriceps and hamstring muscle strength; a fasting lipid profile; and heart rate and oxygen consumption during incremental upper extremity ergometry testing. RESULTS: The 2 children cycling with FES and 1 child cycling passively exhibited improved bone mineral density, muscle volume, stimulated quadriceps strength, and lower resting heart rate. For the second child cycling passively, few changes were realized. Overall, the lipid results were inconsistent, with some positive and some negative changes seen. CONCLUSIONS: This case series suggests that cycling with or without FES may have positive health benefits and was a practical home exercise option for these children with SCI.

Effect of electrical stimulation pattern on the force responses of paralyzed human quadriceps muscles.

Most studies examining the effect of electrical stimulation pattern on the force response of muscle have been done in able-bodied persons. The purpose of this study was to examine the electrically elicited force responses of the paralyzed quadriceps femoris muscles of persons with spinal cord injuries (SCI) to see whether stimulation patterns that increase the force response in non-paralyzed muscle will do so in paralyzed muscle. Thirteen subjects ranging in age from 11 to 24 years old with motor-complete SCI were studied. Isometric muscle performance was tested using 6-pulse constant-frequency trains (CFTs), variable-frequency trains (VFTs), and doublet-frequency trains (DFTs) delivered at mean frequencies of 10, 20, 33, 50, and 100 HZ. In the non-fatigued and fatigued condition, the VFT and DFT peak forces were greater than the CFT peak forces at 10 HZ. In addition, in the fatigued condition the 20-HZ VFT peak forces were greater than the CFT peak forces, and there was a trend for the DFT peak forces to be greater than the CFT peak forces. In the non-fatigued condition, the 33-HZ and 50-HZ DFT force-time integrals were greater than both the CFT and VFT force-time integrals. In the fatigued condition, there was no significant effect of train-type on the force-time integrals. These results differ from those previously reported from studies using able-bodied persons and indicate that findings from studies of the electrically elicited force responses of the muscles of able-bodied persons do not apply to the paralyzed muscles of persons with SCI.

Strengthening of partially denervated knee extensors using percutaneous electric stimulation in a young man with spinal cord injury.

OBJECTIVE: To evaluate the effects of percutaneous electric stimulation on knee extensor strength and muscle hypertrophy, gait, and energy cost of walking in a young man with partial denervation of the knee extensors. DESIGN: One-way repeated measures. SETTING: Pediatric orthopedic hospital. PARTICIPANT: A man in his early twenties, who had an L2 American Spinal Injury Association class D spinal cord injury, presented with strength deficits in his left knee extensors and reported falling frequently. When walking, his left knee remained locked in extension throughout stance. Electromyographic testing revealed chronic denervation and reinnervation changes. INTERVENTION: Because of sensory difficulties with surface stimulation, a percutaneous electrode was surgically implanted near the femoral nerve. The subject exercised isometrically with a research grade stimulator for 1 hour a day until his strength plateaued. MAIN OUTCOME MEASURES: Quadriceps femoris strength and hypertrophy, gait, and energy cost of walking were recorded preintervention, every 2 months during the strengthening phase, and 2 months after withdrawal. RESULTS: Voluntary isometric torque improved from 7 to 14.8Nm (112%) and decreased to 8.5Nm after stimulation was withdrawn. Mean circumferential measures of the thigh improved from 12.3 to 13.5cm (9.8%) and then decreased to 13.1cm. Gait kinematics and kinetics were unchanged, although the subject reported greater stability in his left knee and fewer falls. CONCLUSIONS: The study indicates that percutaneous electric stimulation could be used to strengthen partially denervated muscle and to affect function. However, gains in strength may not be maintained once treatment is withdrawn.

Switching stimulation patterns improves performance of paralyzed human quadriceps muscle.

The clinical efficacy of functional electrical stimulation (FES) is limited by the rapid onset of fatigue. Functional electrical stimulation applications typically stimulate skeletal muscles with constant-frequency trains (CFTs). Our laboratory has identified trains that we call doublet-frequency trains (DFTs) and that produce greater forces than CFTs, but more fatigue during repetitive activation than comparable CFTs. The purpose of this study was to see whether a series of CFTs followed by DFTs would reach a targeted isometric peak force more times than either train type alone during repetitive isometric activation of the paralyzed quadriceps muscles of subjects with spinal cord injuries (SCI). The combination of CFTs followed by DFTs reached the targeted isometric force 14% more often than the CFTs alone and 18% more often than the DFTs alone. These findings confirm that switching train types may be a useful strategy to offset the rapid fatigue of the functionally important quadriceps muscle that persons with SCI experience when using FES.

Mathematical model that predicts isometric muscle forces for individuals with spinal cord injuries.

The ideal functional electrical stimulation (FES) system requires a mathematical model to provide feedforward control of the stimulation parameters such that they are optimal for different individuals across a range of physiological conditions, muscles, and tasks. Recently we tested and validated such a model using able-bodied subjects. The purpose of this study was to determine whether this model applied to persons with spinal cord injuries (SCI). To this end, the isometric force responses of the paralyzed quadriceps femoris muscles of 14 adolescents and young adults were tested. For each subject, the force responses to two six-pulse stimulation trains were used to identify the parameter values of the model and then the model was used to predict the force responses to three train patterns across a range of frequencies in both a nonfatigued and fatigued condition. The intraclass correlation coefficients (ICCs) between the experimental and predicted force-time integrals and peak forces were above 0.90 for 12 of the 13 stimulation trains tested in the nonfatigued condition and all 13 trains tested in the fatigued condition. The success of our model with SCI subjects leads us to believe that our model may be useful for designing optimal stimulation parameters for standing and ambulation in patients who use FES.

Comparison of percutaneous and surface functional electrical stimulation during gait in a child with hemiplegic cerebral palsy.

The purpose of this brief report was to compare the immediate effects of surface functional electrical stimulation (S-FES) and percutaneous functional electrical stimulation (P-FES) of the tibialis anterior applied during gait in a child with hemiplegic cerebral palsy. A three-dimensional gait analysis was conducted while an 11-yr-old girl with right hemiplegia walked with S-FES, P-FES, and no stimulation. The results indicated that both P-FES and S-FES increased dorsiflexion at initial contact, peak dorsiflexion in swing, and mean dorsiflexion in swing compared with walking without stimulation. The increase in dorsiflexion was greater with P-FES as compared with S-FES. Ankle absorption work was improved with both types of stimulation, whereas ankle generation work increased only with P-FES. This report suggests that S-FES and P-FES may have different immediate effects on gait due to issues such as muscle contraction strength, sensory feedback, and control systems for stimulation.

Use of functional electrical stimulation to augment traditional orthopaedic surgery in children with cerebral palsy.

The purpose of this study was to compare the functional outcomes of traditional lower extremity orthopaedic surgery to more limited surgery augmented with functional electrical stimulation (FES) applied while walking. Seventeen ambulatory children with cerebral palsy participated in this prospective pretest-posttest control group study. The surgical group (nine subjects) underwent traditional orthopaedic procedures. The FES group (eight subjects) underwent placement of percutaneous intramuscular FES electrodes and limited orthopaedic surgical procedures. Postoperatively, they were provided with an FES home walking program. One year after intervention, all children (combined data) showed improvements in passive range of motion, gait spatiotemporal parameters, and gross motor function (P < 0.05). No differences were seen between groups before or after intervention. The FES group underwent 4.5 fewer ablative procedures per child than the surgical group. These results suggest that FES in combination with more limited surgery may provide similar functional gains with fewer ablative procedures than traditional orthopaedic surgery.

Direct effect of percutaneous electric stimulation during gait in children with hemiplegic cerebral palsy: a report of 2 cases.

The feasibility of using percutaneous intramuscular functional electric stimulation (FES) in children with cerebral palsy (CP) as a method to improve ankle kinematics and kinetics during gait was investigated. Two children with right hemiplegic CP had percutaneous intramuscular electrodes implanted into the gastrocnemius and tibialis anterior muscles of the involved limb. FES was provided during the gait cycle using force-sensing foot switches to detect gait phase transitions. The children ambulated using FES under 3 conditions (gastrocnemius on, tibialis anterior on, gastrocnemius and tibialis anterior on). For each condition, two 45-minute walking sessions were conducted per day for 1 week. Immediately after each week of practice, a gait analysis was performed at the subject's self-selected walking speed for that stimulation condition and without stimulation. Both children demonstrated improvements in ankle dorsiflexion angle at initial contact, peak dorsiflexion during swing, mean dorsiflexion during swing, and ankle work during early stance with tibialis anterior stimulation alone and combined gastrocnemius and tibialis anterior stimulation. Improvements in ankle work were found during late stance for both children with all stimulation conditions. These results suggest that percutaneous intramuscular FES was effective in improving aspects of ankle kinematics and kinetics of 2 children with hemiplegic CP.

Functional electrical stimulation for augmented walking in adolescents with incomplete spinal cord injury.

BACKGROUND/OBJECTIVE: This study evaluated the effects of functional electrical stimulation (FES) applied to the muscles acting on the pelvis, hip, and knee on muscle strength, energy cost of walking, maximum walking distance and speed, step length and cadence, and joint kinematics during gait in 3 ambulatory adolescents with incomplete spinal cord injury (SCI). METHODS: Percutaneous FES was used to strengthen weakened muscles and to augment walking. After training, participants walked as desired at home with FES for 1 year. Data were collected at baseline (preintervention), and with FES on and FES off immediately following the training period and with FES on and FES off at 3, 6, and 12 months posttraining. RESULTS: Voluntary strength improved in 12 out of 13 stimulated muscles. Decreased energy cost, increased maximum walking distance and speed, increased step length, and improved joint kinematics during gait were demonstrated with FES on and FES off. DISCUSSION: FES was able to achieve selective stimulation of key weakened muscles for augmented walking. The data suggest that FES had both direct and carryover effects.

Three-year follow-up of an implanted functional electrical stimulation system for upright mobility in a child with a thoracic level spinal cord injury.

PURPOSE: The purpose of this study was to compare the use of a functional electrical stimulation (FES) system with the use of knee-ankle-foot orthoses (KAFO) for upright mobility over a 3-year period in a child with a spinal cord injury (SCI). METHODS: A 13-year-old boy with a T8 complete SCI received a lower extremity implanted FES system. Electrodes were implanted for knee extension and for hip extension, abduction, and adduction. After training and at annual intervals, independence and timeliness in completing 7 upright mobility activities with FES and KAFO, as well as stimulated muscle strength, were assessed. RESULTS: Results have shown that FES provided independence equal to that of KAFO for all activities. Four activities were accomplished more quickly with FES, including donning the system, reaching a high object, transferring to a high surface, and walking 6 m. A floor-to-stand transfer was faster with KAFO. Functional results and stimulated muscle strength have remained stable over the 3-year period. CONCLUSION: The results indicate that FES can provide function equal to or faster than KAFO in a child with a T8 complete SCI and that performance with the FES system can remain stable for at least 3 years.