Efficacy Of Functional Electrical Stimulation Research Articles

Efficacy of functional electrical stimulation of the lower extremities in stroke patients

Aim. To evaluate the efficacy of functional electrical stimulation of the lower extremities in stroke patients at different stages of motor rehabilitation.Materials and methods. The study involved 80 patients with motor disorders after stroke. The studied treatment methods included passive and passive-active functional electrical stimulation (FES) in combination with the THERATrainer Tigo and active FES (neuro-orthosis) WalkAide.Results. The analysis of motor status indicators, namely the Berg Balance Scale, 6-minute walk test, and dynamic walking index showed the maximum efficacy of active FES with biofeedback.Conclusion. When prescribing and selecting a method of electrical stimulation, preference in neurorehabilitation should be given to methods of passive-active and active functional stimulation.

Inflammation and altered metabolism impede efficacy of functional electrical stimulation in critically ill patients

BackgroundCritically ill patients suffer from acute muscle wasting, which is associated with significant physical functional impairment. We describe data from nested muscle biopsy studies from two trials of functional electrical stimulation (FES) that did not shown improvements in physical function.MethodsPrimary cohort: single-centre randomized controlled trial. Additional healthy volunteer data from patients undergoing elective hip arthroplasty. Validation cohort: Four-centre randomized controlled trial. Intervention: FES cycling for 60-90min/day. Analyses: Skeletal muscle mRNA expression of 223 genes underwent hierarchal clustering for targeted analysis and validation.ResultsPositively enriched pathways between healthy volunteers and ICU participants were “stress response”, “response to stimuli” and “protein metabolism”, in keeping with published data. Positively enriched pathways between admission and day 7 ICU participants were “FOXO-mediated transcription” (admission = 0.48 ± 0.94, day 7 = − 0.47 ± 1.04 mean log2 fold change; P = 0.042), “Fatty acid metabolism” (admission = 0.50 ± 0.67, day 7 = 0.07 ± 1.65 mean log2 fold change; P = 0.042) and “Interleukin-1 processing” (admission = 0.88 ± 0.50, day 7 = 0.97 ± 0.76 mean log2 fold change; P = 0.054). Muscle mRNA expression of UCP3 (P = 0.030) and DGKD (P = 0.040) decreased in both cohorts with no between group differences. Changes in IL-18 were not observed in the validation cohort (P = 0.268). Targeted analyses related to intramuscular mitochondrial substrate oxidation, fatty acid oxidation and intramuscular inflammation showed PPARγ-C1α; (P < 0.001), SLC25A20 (P = 0.017) and UCP3 (P < 0.001) decreased between admission and day 7 in both arms. LPIN-1 (P < 0.001) and SPT1 (P = 0.044) decreased between admission and day 7. IL-18 (P = 0.011) and TNFRSF12A (P = 0.009) increased in both arms between admission and day 7. IL-1β (P = 0.007), its receptor IL-1R1 (P = 0.005) and IL-6R (P = 0.001) decreased in both arms between admission and day 7. No between group differences were seen in any of these (all p > 0.05).ConclusionsIntramuscular inflammation and altered substrate utilization are persistent in skeletal muscle during first week of critical illness and are not improved by the application of Functional Electrical Stimulation-assisted exercise. Future trials of exercise to prevent muscle wasting and physical impairment are unlikely to be successful unless these processes are addressed by other means than exercise alone.

Efficacy of functional electrical stimulation in rehabilitating patients with foot drop symptoms after stroke and its correlation with somatosensory evoked potentials—a crossover randomised controlled trial

ObjectiveThe connectivity between somatosensory evoked potentials (SEPs) and cortical plasticity remains elusive due to a lack of supporting data. This study investigates changes in pathological latencies and amplitudes of SEPs caused by an acute stroke after 2 weeks of rehabilitation with functional electrical stimulation (FES). Furthermore, changes in SEPs and the efficacy of FES against foot drop (FD) stroke symptoms were correlated using the 10-m walk test and foot–ankle strength.MethodsA randomised controlled two-period crossover design plus a control group (group C) was designed. Group A (n = 16) was directly treated with FES, while group B (n = 16) was treated after 2 weeks. The untreated control group of 20 healthy adults underwent repeated SEP measurements for evaluation only.ResultsThe repeated-measures ANOVA showed a decrease in tibial nerve (TN) P40 and N50 latencies in group A after the intervention, followed by a decline in non-paretic TN SEP in latency N50 (p < 0.05). Moreover, compared to groups B and C from baseline to 4 weeks, group A showed a decrease in paretic TN latency P40 and N50 (p < 0.05). An increase in FD strength and a reduction in step cadence in group B (p < 0.05) and a positive tendency in FD strength (p = 0.12) and step cadence (p = 0.08) in group A were observed after the treatment time. The data showed a moderate (r = 0.50–0.70) correlation between non-paretic TN latency N50 and step cadence in groups A and B after the intervention time.ConclusionThe FES intervention modified the pathological gait in association with improved SEP afferent feedback.Registered on 25 February 2021 on ClinicalTrials.gov under identifier number: NCT04767360.

2 - Feasibility and efficacy of Functional Electrical Stimulation (FES) in children with non-neurogenic lower urinary tract dysfunction

2 - Feasibility and efficacy of Functional Electrical Stimulation (FES) in children with non-neurogenic lower urinary tract dysfunction

Clinical Efficacy of Functional Electrical Stimulation-assisted Rehabilitation Cycling on the Function of Lower Limbs in Patients with Stroke.

To explore the efficacy of functional electrical stimulation (FES)-assisted rehabilitation cycling on the functional recovery of lower limbs in patients with hemiplegic stroke and the assessment value of surface electromyography (sEMG). A total of 66 patients with stroke accompanied by hemiplegia of the lower limbs were enrolled in the present prospective study and randomly divided into the experimental group and control group, with 33 patients in each group. FES-assisted rehabilitation cycling was applied in the experimental group, while only rehabilitation cycling was performed without setting the stimulation parameters in the control group. sEMG and the Fugl-Meyer assessment (FMA) were carried out, and the modified Barthel index (MBI) of the lower limbs was assessed before treatment and after 4 weeks and 8 weeks of treatment. There were no significant differences in the evaluation results of sEMG, FMA, and MBI of the lower limbs between the two groups of patients before the treatment (p > 0.05). After 4 weeks of treatment, compared with the control group, there were significant differences in the results of sEMG, FMA, and MBI of the lower limbs in the experimental group (p < 0.05). In the experimental group, the difference in sEMG was statistically significant (p < 0.05). After 8 weeks of treatment, compared with the control group, there were significant differences in the results of sEMG, FMA, and MBI of the lower limbs in the experimental group (p < 0.05). In the experimental group, the differences in the results of sEMG, FMA, and MBI of the lower limbs were statistically significant (p < 0.05). The inter-group comparison of the results of sEMG, FMA and MBI of the lower limbs was statistically significant (p < 0.05) in the control group. FES-assisted rehabilitation cycling might promote the recovery of the motor function of the lower limbs in patients with stroke and improve the sEMG signal of the lower limbs.

Сomplex rehabilitation of walking function in central paresis of the lower limb using neuroprosthetic technology

Disability after a stroke is most often associated with decreased patient activity due to walking disorder. In case of severe paresis, the function of the limb in the early stages of recovery is advisable to support with the help of partial prosthetics, using methods that provide functional stimulation. The complex treatment of central paresis includes botulinum therapy, which is due to the high incidence of spasticity.&#x0D; Aim: of the study: evaluation of the efficacy of functional electrical stimulation in a complex of multimodal effects in restoring movement in stroke patients with lower limb paresis.&#x0D; Materials and methods: Stimulation and neuroprosthetic methods (Bioness L300) were used as the main therapeutic program of rehabilitation treatment for patients with motor disorders of the lower limb after an ischemic stroke (n = 70). The median period of stroke was 21 [11; 47] days, median age 54 [42; 65] years. Scales and questionnaires were used to assess the loss of strength and volume of movement disorders, spasticity, walking speed and self-care (Medical Research Council Weakness Scale (1981, MRC), Barthel Index (1965), Modified Ashworth Scale (MAS), 10-meter test).&#x0D; Results: The effectiveness of personalized therapy with the use of a neuroprothesis (Bioness L300) in patients in the acute and early recovery period of ischemic stroke was shown. The additional use of botulinum toxin made it possible to eliminate the inhibitory effect of spasticity, which expanded the possibility of using intensive methods of physical rehabilitation. There was an increase in daily activity, walking speed, and the level of self-care of patients in 90 % of cases.&#x0D; Conclusion: The use of a complex of stimulating personalized techniques in the acute period of a stroke is justified and safe. The functional electrical stimulation helps to overcome power paresis, increases the overall level of physical activity of patients after a stroke, motivation for recovery and improves the quality of life. (1 figure, 2 tables, bibliography: 9 refs)

Neuroprosthetic Technology «Bioness» (Exorobot) in the Process of Restoring Motor and Vegetative-Trophic Disorders in Central Paresis of the Upper Limb

Disability after a stroke or brain injury is most often associated with impaired movement, speech, swallowing, and reduced cognitive abilities. By the end of the acute period of stroke, paresis in the arm and leg of varying degrees is observed in 80-90 % of survivors.In case of severe paresis, it is advisable to support the function of the limb at the early stages of recovery using modern specialized modifiable devices and methods that provide functional and multimodal stimulation and partial prosthetics. Aim of the study: evaluation of the efficacy of functional electrical stimulation (FES) in a complex of multimodal effects in restoring movement in Stroke patients with upper limb paresis (palcy).Methods. Stimulation and neuroprosthetic methods (FES - “Bioness H200”, RTMs) were used as the main therapeutic program of rehabilitation treatment for patients with motor disorders of the upper limb after an ischemic stroke (n=140). The median period of stroke was 25 [13; 56] days, median age 52 [48; 69] years. The standard methods of diagnosis and treatment of patients with stroke in accordance to the protocol of the Ministry of health of the Russian Federation No. 928 n and 1705 n (2012) were used, as well as scales and questionnaires for assessing the loss of strength and volume of motor disorders, assessing depression and motivation for treatment (Motricity Index), Fugl-Meyer AR, Medical Research Council Weakness Scale, Modified Ashworth Scale (MAS), Beck Depression Inventory; Beck At, Recovery Locus of Control, Patridge C., Johnstone M. Results. The effectiveness of personalized therapy with the use of a neuroprosthesis (“Bioness H200”) in patients in the acute period of ischemic stroke was shown, with the Motrisight index, Fugle-Meier scale being the most sensitive scales. the results depend on thebasic disease characteristics, the most relevant of which were - focus, degree of neurological deficit, personal motivation. The addition using of botulinum toxin allowed eliminating the inhibitory effect of spasticity, which prepared patients for intensive methods of physical rehabilitation. During the follow-up period, no complications were revealed. In 90% of cases, an increase in daily activity was noted. Functional electrical stimulation has significantly increased their level of self-care. The disability complex was initially equally pronounced in all patients, but positive reinforcement in the form of movement of the paretic hand against the background of FES led to a decrease in the severity of depression. In 100%, there was a high motivation to continue the treatment program with neuroprosthetics. Conclusion. The use of a complex of stimulating personalized techniques in the acute period of stroke is justified and safe. The useof FES significantly increases the range of motion in the hand, helps to overcome power paresis, coordination disorders, increases the general level of physical activity of patients after a stroke, motivation for the recovery process and improves the quality of life.

Functional electrical stimulation cycling, goal-directed training, and adapted cycling for children with cerebral palsy: a randomized controlled trial.

To test the efficacy of functional electrical stimulation (FES) cycling, goal-directed training, and adapted cycling, compared with usual care, to improve function in children with cerebral palsy (CP). The intervention was delivered between 2017 and 2019 and included three sessions per week for 8 weeks (2×1h sessions at a children's hospital, and 1h home programme/week). Hospital sessions included 30 minutes of FES cycling and 30 minutes of goal-directed training. Home programmes included goal-directed training and adapted cycling. The comparison group continued usual care. Primary outcomes were gross motor function assessed by the Gross Motor Function Measure (GMFM) and goal performance/satisfaction assessed using the Canadian Occupational Performance Measure (COPM). Secondary outcomes were sit-to-stand and activity capacity, participation in home, school, and community activities, and power output. Linear regression was used to determine the between-group mean difference immediately post-training completion after adjusting for baseline scores. This randomized controlled trial included 21 participants (mean age=10y 3mo, standard deviation [SD]=3y; Gross Motor Function Classification System level: II=7, III=6, IV=8) who were randomized to the intervention (n=11) or usual care group (n=10). Between-group differences at T2 favoured the intervention group for GMFM-88 (mean difference=7.4; 95% confidence interval [CI]: 2.3-12.6; p=0.007), GMFM-66 (mean difference=5.9; 95% CI: 3.1-8.8; p<0.001), COPM performance (mean difference=4.4; 95% CI: 3.9-5.3; p<0.001) and satisfaction (mean difference=5.2; 95% CI: 4.0-6.4; p<0.001). Children with CP achieved meaningful functional improvements after FES cycling, goal-directed training, and adapted cycling training. Cycling programmes for children with CP should be individualized and goal directed.

Functional Electrical Stimulation: A Possible Strategy to Improve Muscle Function in Central Core Disease?

Central Core Disease (CCD) is a congenital myopathy characterized by presence of amorphous central areas (or cores) lacking glycolytic/oxidative enzymes and mitochondria in skeletal muscle fibers. Most CCD families are linked to mutations in ryanodine receptor type-1 (RYR1), the gene encoding for the sarcoplasmic reticulum (SR) Ca2+ release channel of skeletal muscle. As no treatments are available for CCD, currently management of patients is essentially based on a physiotherapic approaches. Functional electrical stimulation (FES) is a technique used to deliver low energy electrical impulses to artificially stimulate selected skeletal muscle groups. Here we tested the efficacy of FES in counteracting muscle loss and improve function in the lower extremities of a 55-year-old female patient which was diagnosed with CCD at the age of 44. Genetic screening of the RyR1 gene identified a missense mutation (c.7354C>T) in exon 46 resulting in an amino acid substitution (p.R2452W) and a duplication (c.12853_12864dup12) in exon 91. The patient was treated with FES for 26 months and subjected before, during, and after training to a series of functional and structural assessments: measurement of maximum isometric force of leg extensor muscles, magnetic resonance imaging, a complete set of functional tests to assess mobility in activities of daily living, and analysis of muscle biopsies by histology and electron microscopy. All results point to an improvement in muscle structure and function induced by FES suggesting that this approach could be considered as an additional supportive measure to maintain/improve muscle function (and possibly reduce muscle loss) in CCD patients.

Efficacy of EMG/Bioimpedance-Triggered Functional Electrical Stimulation on Swallowing Performance.

In order to support swallowing, the efficacy of functional electrical stimulation for different stimulation settings of the submental musculature has been investigated. The stimulation was administrated at rest and synchronously to voluntary initiated swallows. The onset of a swallow was detected in real-time by a combined electromyography/ bioimpedance measurement at the neck in order to trigger the stimulation. The amplitude and speed of larynx elevation caused by the FES has been assessed by the observed change in bioimpedance whereas a reduction of bioimpedance corresponds to an increase in larynx elevation. Study results from 40 healthy subjects revealed that 73% of the subjects achieved a larger and faster larynx elevation during swallowing with triggered FES and therefor a better protection of their airways. However, we also observed a decrease in larynx elevation compared to normal swallowing in 11 out of the 40 subjects what might not benefit from such a treatment. The largest improvement of larynx elevation and speed during swallowing could be achieved with three stimulation channels formed by four electrodes in the submental region.

The Efficacy of Functional Electrical Stimulation of the Abdominal Muscles in the Treatment of Chronic Constipation in Patients with Multiple Sclerosis: A Pilot Study.

Chronic constipation in patients with multiple sclerosis (MS) is common and the current methods of treatment are ineffective in some patients. Anecdotal observations suggest that functional electrical stimulation (FES) of the abdominal muscles may be effective in the management of constipation in these patients. Patients and Methods. In this exploratory investigation we studied the effects of FES on the whole gut transit time (WGTT) and the colonic transit time (CTT). In addition, we evaluated the treatment effect on the patients' constipation-related quality of life and on the use of laxatives and the use of manual bowel evacuation. FES was given for 30 minutes twice a day for a period of six weeks. Four female patients were studied. Results. The WGTT and CTT and constipation-related quality of life improved in all patients. The patients' use of laxatives was reduced. No adverse effects of FES treatment were reported. Conclusion. The findings of this pilot study suggest that FES applied to the abdominal muscles may be an effective treatment modality for severe chronic constipation in patients with MS.

Effect of a Foot-Drop Stimulator and Ankle–Foot Orthosis on Walking Performance After Stroke

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.

Analysis of Body Response to Functional Electrical Stimulation on Hemiphlegic Subjects Using Higher Order Spectra

Hemiplegia is a clinical condition where one-half of the body loses its function. It often occurs after a stroke, head injury or other neurological disorders those disrupt the cerebral circulation. Functional Electrical Stimulation (FES) is a rehabilitation engineering method, used to restore or improve the lost functions. FES uses low levels of electrical current to stimulate the nerves and in turn contract the affected muscles. In our work, we use EMG signals as the input to evaluate the efficacy of FES in improving the body movement of hemiplegic subjects. The response of the muscle to the stimulation produced by FES is then captured in accelerometer signals. We measure EMG signals (a) with FES applied and (b) without FES. Higher Order Spectrum (HOS) has been used in the analysis of these accelerometer signals. We extracted HOS features from accelerometer signals with and without FES. Our results show higher values for HOS features in case of EMG without FES than when FES is applied, indicating that FES is able to restore the rhythmicity of the muscles of the hemiplegic subjects. For the analysis, Bispectrum plots and Bicoherence plots for the four cases of accelerometer signals has been taken into consideration, such as (i) no FES applied, (ii) FES applied to nerves only, (iii) FES applied to muscles only and (iv) FES applied to both nerves and muscles. We have found that all these plots are

Functional Electrical Stimulation Therapy for Grasping in Traumatic Incomplete Spinal Cord Injury: Randomized Control Trial

The purpose of this single-site randomized control trial was to assess the short-term and long-term efficacy of functional electrical stimulation (FES) therapy over conventional occupational therapy in improving voluntary hand function in incomplete C4-C7 spinal cord injury individuals. All 22 participants recruited in this randomized control trial received treatment for both the left and right upper extremities. Every participant, irrespective of group allocation, received one dose (60 min per day, 5 days per week for the duration of 8 weeks) of conventional occupational therapy for hand function. Of the 22 participants, 12 individuals received an additional dose of conventional occupational therapy, while the remaining 10 participants received a dose of FES hand therapy. The primary outcome measure was Functional Independence Measure (FIM) self-care subscore. The secondary outcome measures were Spinal Cord Independence Measure (SCIM) self-care subscore and Toronto Rehabilitation Institute Hand Function Test (TRI-HFT). The participants who received FES therapy showed significantly greater improvements in hand function at discharge, and were able to maintain their gains at long-term follow-up as assessed using FIM self-care subscore, SCIM self-care subscore, and TRI-HFT. The FES therapy effectively increased independence and thereby improved quality of life of individuals with tetraplegia when compared with conventional occupational therapy.

Recent Findings Regarding the Efficacy of Functional Electrical Stimulation in Patients With Chronic Hemiplegia and Multiple Sclerosis: A Narrative Literature Review

In Brief In recent years, numerous studies have reported the effects of functional electrical stimulation (FES) in the management of foot drop. The purpose of this article is to review these latest findings according to both the diagnoses and various functional domains of the individual clinical trials. These findings support the assertion that FES systems facilitate both immediate and extended improvements in gait velocity across both smooth and irregular surfaces in patients with chronic hemiparesis. In addition, beneficial effects on the symmetry and rhythmicity of gait, along with positive “therapeutic” or “carry-over” effects, have been identified. Patient-derived data indicate high acceptance rates and may provide further insights into what aspects of FES usage are perceived by patients to be the most beneficial. Any empirical advantages of FES systems over ankle-foot orthoses for patients with chronic hemiparesis seem to require a degree of acclimation to the FES intervention. Recent evidence supports the efficacy of an orthotic effect associated with the use of FES during both short-distance and endurance walking events among patients with more debilitating multiple sclerosis (MS). In contrast, the use of FES by less debilitated patients with MS does not seem to increase the speed of short-distance walking events. The benefit of FES interventions during endurance walking events in less debilitated patients has not been evaluated. To the limited extent that it has been investigated, there is no apparent evidence of a therapeutic or a carry-over effect associated with FES among the more debilitating forms of MS. This effect has not been investigated among more functional walkers with MS. This paper reviews recent research relating to the effects of functional electrical stimulation (FES) in the management of foot drop according to both the diagnoses and various functional domains of the individual clinical trials.

Restoration of gait and motor recovery by functional electrical stimulation therapy in persons with stroke

Purpose. To evaluate the clinical efficacy of functional electrical stimulation (FES) therapy of the tibialis anterior (TA) muscle on gait restoration and enhancing motor recovery with stroke patients.Method. Thirty hemiparetic participants with spastic foot-drop impairments who were at least 3 months post-stroke were recruited from a rehabilitation institute and were assigned either to a control group or a FES group. Both the groups participated in a conventional stroke rehabilitation program for 60 min per day, 5 days a week, for 12-weeks. The FES group received the electrical stimulation to the TA muscle for correction of foot-drop.Results. Functional electric stimulation (FES) resulted in a 26.3% (p < 0.001) improvement of walking speed measured with 10-m walkway, whereas the improvement in the control group was only 11.5% (p < 0.01). The FES group also showed significantly greater improvements compared to control group in other gait parameters (e.g. cadence, step length), physiological cost index (PCI), ankle range of motion, spasticity of calf muscle, Fugl–Meyer scores, and the maximum value of the root mean square (RMSmax), which reflects the capacity of the muscle output.Conclusions. These findings suggest that, the FES therapy combined with conventional therapy treatment more effectively improves the walking ability and enhances the motor recovery when compared with conventional therapy alone in stroke survivors.

Surface-applied functional electrical stimulation for orthotic and therapeutic treatment of drop-foot after stroke – a systematic review

Objectives: Drop-foot when incurred as a deficit post-stroke significantly contributes to the development of physical disability and social restriction. The condition is most commonly treated using a custom moulded ankle foot orthosis (AFO) or functional electrical stimulation (FES). No previous systematic review has assessed the evidence for both an orthotic (while the device is still on) and therapeutic (when the device is no longer worn) effect of FES, including all types of methodology and outcome measure. This is certainly a gap in the literature in terms of informing the practising clinician.Methods: A systematic search was conducted to identify all articles published between 1990 and 2008 relating to the effectiveness of FES for the treatment of drop-foot post-stroke using strict inclusion/exclusion criteria. Included literature was quality-appraised according to the Guidelines for Cochrane reviewers.Results: Thirty studies were analysed (264 excluded) and results support the conclusion that FES can have a positive orthotic effect particularly for gait speed and physiological cost index (PCI), in chronic post-stroke patients. Research supporting a therapeutic effect of FES post-stroke is less conclusive. Some support exists for FES in combination with 'conventional rehabilitation' or treadmill training or for increasing the effectiveness of Botulinum toxin injections.Discussion: While more evidence exists to support an orthotic than therapeutic effect of FES, further research is needed to define the extent of a therapeutic effect (particularly in acute patients) and compare the efficacy of FES with an AFO. More standardisation of protocols and a more collaborative approach between engineers, researchers, clinicians and users is required.

Contractile Properties and the Force-Frequency Relationship of the Paralyzed Human Quadriceps Femoris Muscle

Following spinal cord injury (SCI), paralyzed muscles undergo physiological changes that alter their force responses to electrical stimulation. The purpose of this study was to investigate the effects of SCI on the contractile properties and force-frequency relationship (FFR) of the paralyzed human quadriceps femoris muscle of adolescents and young adults. Thirteen subjects (11 male, 2 female; age range=11-24 years) with motor complete SCIs and 13 matched control subjects (11 male, 2 female; age range=9-23 years) without SCI participated in the study. Both groups of subjects underwent the same testing protocol using similar equipment. The paralyzed muscles of the subjects with SCI produced 62% of the peak twitch force and had a fatigue ratio that was 65% of that of the control subjects. The paralyzed muscles contracted 14% and 25% faster and relaxed 38% and 46% faster than the nonparalyzed muscles in nonfatigued and fatigued conditions, respectively. Compared with the control subjects, the subjects with SCI had twitch-to-tetanus ratios that were 84% and 127% greater in nonfatigued and fatigued conditions, respectively. Relative to the control subjects, the FFR of the subjects with SCI was shifted to the left in the fatigued condition. Relative to their respective nonfatigued conditions, the FFR of both groups of subjects shifted to the right with fatigue. These findings may have important implications for designing stimulation strategies to reduce the rapid fatigue that limits the clinical efficacy of functional electrical stimulation.

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.

Functional electrical stimulation for detrusor instability.

The clinical efficacy of functional electrical stimulation (FES) for female detrusor instability (DI) is reviewed. Various types of FES methods (including anogenital long-term stimulation, short-term maximal stimulation, implantable stimulation and transcutaneous stimulation) have been reported. The therapeutic effects of these approaches were similar: the percentage of patients improved has been reported to be in the range 50%-90%. FES for female DI is a non-destructive procedure with a curative effect and very few side effects. This curative effect (re-education) is a major benefit of FES.