Cyclic Electrical Stimulation Research Articles

Prefrontal cortex activity of active motion, cyclic electrical muscle stimulation, assisted motion, and imagery of wrist extension in stroke using fNIRS

ObjectivesThis study aimed to determine whether the prefrontal cortex (PFC) was activated during four training approaches for wrist extension in patients with stroke, including active motion, cyclic electrical muscle stimulation (EMS), assisted motion, and motor imagery (MI). Materials and MethodsWe conducted a cross-sectional study involving 16 patients with stroke, and adopted functional near-infrared spectroscopy (fNIRS) to observe PFC activity during four treatment paradigms. The beta value of 53 channels in fNIRS under each paradigm, compared to the baseline, was evaluated using single sample t-test. The one-way analysis of variance with post hoc analysis was employed to compare the difference of significantly activated channels among four treatment paradigms. ResultsThis study revealed that the active motion (t values ranging from 2.399 to 4.368, p values <0.05), as well as MI of wrist extension (t values ranging from 2.161 to 4.378, p values <0.05), significantly increased HBO concentration across the entire PFC. The cyclic EMS enhanced the activation of Broca's area and frontal pole (FP) (t values ranging from -2.540 to 2.303, p values <0.05). The assisted motion induced significant activation in Broca's area, dorsolateral prefrontal cortex, and FP (t values ranging from -2.226 to 3.056, p values <0.05). The difference in ΔHBO among the four tasks was seen in Broca's area, FP, and frontal eye field. ConclusionsActive wrist extension and MI activate most PFC areas, whereas assisted motion and single-use of cyclic EMS have limited effectiveness for PFC activation in stroke patients.

Cyclic Strain and Electrical Co-stimulation Improve Neural Differentiation of Marrow-Derived Mesenchymal Stem Cells.

The current study investigated the combinatorial effect of cyclic strain and electrical stimulation on neural differentiation potential of rat bone marrow-derived mesenchymal stem cells (BMSCs) under epidermal growth factor (EGF) and fibroblast growth factor 2 (FGF2) inductions in vitro. We developed a prototype device which can provide cyclic strain and electrical signal synchronously. Using this system, we demonstrated that cyclic strain and electrical co-stimulation promote the differentiation of BMCSs into neural cells with more branches and longer neurites than strain or electrical stimulation alone. Strain and electrical co-stimulation can also induce a higher expression of neural markers in terms of transcription and protein level. Neurotrophic factors and the intracellular cyclic AMP (cAMP) are also upregulated with co-stimulation. Importantly, the co-stimulation further enhances the calcium influx of neural differentiated BMSCs when responding to acetylcholine and potassium chloride (KCl). Finally, the phosphorylation of extracellular-signal-regulated kinase (ERK) 1 and 2 and protein kinase B (AKT) was elevated under co-stimulation treatment. The present work suggests a synergistic effect of the combination of cyclic strain and electrical stimulation on BMSC neuronal differentiation and provides an alternative approach to physically manipulate stem cell differentiation into mature and functional neural cells in vitro.

A Randomized Controlled Trial Comparing Electromyography-Triggered, Cyclic, and Sensory Electrical Stimulation

Abstract Date Presented 03/28/20 Stroke-induced arm weakness is a leading cause of worldwide disability. OT practitioners commonly employ this modality, but it is unclear which type of electrical stimulation works best for people with stroke-induced weakness. This study compared the efficacy of three types of electrical stimulation for people zero to six months poststroke. We found that all three types of stimulation worked equally well. Primary Author and Speaker: Stephen Page Contributing Authors: John Chae, Richard Wilson

Effectiveness of electrical stimulation therapy in improving arm function after stroke: a systematic review and a meta-analysis of randomised controlled trials

Objective: The aim of this study is to investigate the effectiveness of electrical stimulation in arm function recovery after stroke. Methods: Data were obtained from the PubMed, Cochrane Library, Embase, and Scopus databases from their inception until 12 January 2019. Only randomized controlled trials (RCTs) reporting the effects of electrical stimulation on the recovery of arm function after stroke were selected. Results: Forty-eight RCTs with a total of 1712 patients were included in the analysis. The body function assessment, Upper-Extremity Fugl-Meyer Assessment, indicated more favorable outcomes in the electrical stimulation group than in the placebo group immediately after treatment (23 RCTs (n = 794): standard mean difference (SMD) = 0.67, 95% confidence interval (CI) = 0.51–0.84) and at follow-up (12 RCTs (n = 391): SMD = 0.66, 95% CI = 0.35–0.97). The activity assessment, Action Research Arm Test, revealed superior outcomes in the electrical stimulation group than those in the placebo group immediately after treatment (10 RCTs (n = 411): SMD = 0.70, 95% CI = 0.39–1.02) and at follow-up (8 RCTs (n = 289): SMD = 0.93, 95% CI = 0.34–1.52). Other activity assessments, including Wolf Motor Function Test, Box and Block Test, and Motor Activity Log, also revealed superior outcomes in the electrical stimulation group than those in the placebo group. Comparisons between three types of electrical stimulation (sensory, cyclic, and electromyography-triggered electrical stimulation) groups revealed no significant differences in the body function and activity. Conclusion: Electrical stimulation therapy can effectively improve the arm function in stroke patients.

The Influence of the Timing of Cyclic Load Application on Cardiac Cell Contraction.

Cardiac cells are subjected to mechanical load during each heart-beat. Normal heart load is essential for physiological development and cardiac function. At the same time, excessive load can induce pathologies such as cardiac hypertrophy. While the forces working on the heart as an organ are well-understood, information regarding stretch response at the cellular level is limited. Since cardiac stretch-response depends on the amplitude and pattern of the applied load as well as its timing during the beating cycle, the directionality of load application and its phase relative to action potential generation must be controlled precisely. Here, we design a new experimental setup, which enables high-resolution fluorescence imaging of cultured cardiac cells under cyclic uniaxial mechanical load and electrical stimulation. Cyclic stretch was applied in different phases relative to the electrical stimulus and the effect on cardiac cell beating was monitored. The results show a clear phase-dependent response and provide insight into cardiac response to excessive loading conditions.

The effects of electromyography-triggered electrical stimulation on shoulder subluxation, muscle activation, pain, and function in persons with stroke: A pilot study.

The purpose of this study was to examine the effects of task-oriented electromyography-triggered stimulation for shoulder subluxation, muscle activation, pain and upper extremity function in hemiparetic stroke patients. Twenty participants with subacute hemiparetic stroke were recruited for this study and were randomly divided into two groups: experimental group (n = 10) and control group (n = 10). Subjects in the experimental group participated in task-oriented electromyography triggered stimulation for 30 minutes, five times a week for four weeks, whereas the control group received cyclic functional electrical stimulation for 30 minutes, five times a week for four weeks. Subjects in both groups received conventional physical therapy for four weeks (30 min/day, five times/week). Data collected included the degree of shoulder subluxation which had been confirmed by X-ray, muscle activation of the supraspinatus and posterior deltoid muscles by electromyography, pain by the Visual Analogue Scale (VAS), and hand function by the Fugl-Meyer Assessment (FMA) before and after the four week exercise period. The results showed significant improvement in shoulder subluxation, muscle activation, and VAS results in the experimental group, compared with the control group(p < 0.05). FMA scores showed no significant differences between the two groups. In conclusion, task-oriented electromyography-triggered stimulation improved shoulder subluxation, muscle activation, pain and upper extremity function. These results suggest that task-oriented electromyography-triggered stimulation is effective and beneficial for individuals with subacute stroke, and that further studies should be conducted on multivarious anatomical regions.

Systematic review of adjunct therapies to improve outcomes following botulinum toxin injection for treatment of limb spasticity

Objective: To determine the quality of evidence from randomized controlled trials on the efficacy of adjunct therapies following botulinum toxin injections for limb spasticity. Data sources: MEDLINE, EMBASE, CINAHL, and Cochrane Central Register of Controlled Trials electronic databases were searched for English language human studies from 1980 to 21 May 2015. Study selection: Randomized controlled trials assessing adjunct therapies postbotulinum toxin injection for treatment of spasticity were included. Of the 268 studies screened, 17 met selection criteria. Data extraction: Two reviewers independently assessed risk of bias using the Physiotherapy Evidence Database (PEDro) scale and graded according to Sackett’s levels of evidence. Data synthesis: Ten adjunct therapies were identified. Evidence suggests that adjunct use of electrical stimulation, modified constraint-induced movement therapy, physiotherapy (all Level 1), casting and dynamic splinting (both Level 2) result in improved Modified Ashworth Scale scores by at least 1 grade. There is Level 1 and 2 evidence that adjunct taping, segmental muscle vibration, cyclic functional electrical stimulation, and motorized arm ergometer may not improve outcomes compared with botulinum toxin injections alone. There is Level 1 evidence that casting is better than taping, taping is better than electrical stimulation and stretching, and extracorporeal shock wave therapy is better than electrical stimulation for outcomes including the Modified Ashworth Scale, range of motion and gait. All results are based on single studies. Conclusion: There is high level evidence to suggest that adjunct therapies may improve outcomes following botulinum toxin injection. No results have been confirmed by independent replication. All interventions would benefit from further study.

Effects of combining mental practice with electromyogram-triggered electrical stimulation for stroke patients with unilateral neglect.

[Purpose] The aim of this study was to investigate the effect of mental practice combined with electromyogram-triggered electrical stimulation on neglect and activities of daily living in stroke patients with unilateral neglect. [Subjects and Methods] Thirty-three stroke patients with unilateral neglect were recruited from a local university hospital, and were divided into two groups. The experimental group received an intervention consisting of mental practice combined with electromyogram-triggered electrical stimulation on the neglected side, while the control group received cyclic electrical stimulation at the same site. In addition, both groups received an identical intervention of conventional occupational and physical therapy. [Results] After the intervention, the experimental group showed a statistically significant improvement in the line bisection test result, star cancellation test result, and Catherine Bergego Scale scores. The control group showed a significant improvement only in the line bisection test result. [Conclusion] These data suggest that mental practice combined with electromyogram-triggered electrical stimulation is an effective, novel treatment for reducing unilateral neglect in stroke patients.

Integrated wireless fast-scan cyclic voltammetry recording and electrical stimulation for reward-predictive learning in awake, freely moving rats

Objective. Fast-scan cyclic voltammetry (FSCV) is commonly used to monitor phasic dopamine release, which is usually performed using tethered recording and for limited types of animal behavior. It is necessary to design a wireless dopamine sensing system for animal behavior experiments. Approach. This study integrates a wireless FSCV system for monitoring the dopamine signal in the ventral striatum with an electrical stimulator that induces biphasic current to excite dopaminergic neurons in awake freely moving rats. The measured dopamine signals are unidirectionally transmitted from the wireless FSCV module to the host unit. To reduce electrical artifacts, an optocoupler and a separate power are applied to isolate the FSCV system and electrical stimulator, which can be activated by an infrared controller. Main results. In the validation test, the wireless backpack system has similar performance in comparison with a conventional wired system and it does not significantly affect the locomotor activity of the rat. In the cocaine administration test, the maximum electrically elicited dopamine signals increased to around 230% of the initial value 20 min after the injection of 10 mg kg−1 cocaine. In a classical conditioning test, the dopamine signal in response to a cue increased to around 60 nM over 50 successive trials while the electrically evoked dopamine concentration decreased from about 90 to 50 nM in the maintenance phase. In contrast, the cue-evoked dopamine concentration progressively decreased and the electrically evoked dopamine was eliminated during the extinction phase. In the histological evaluation, there was little damage to brain tissue after five months chronic implantation of the stimulating electrode. Significance. We have developed an integrated wireless voltammetry system for measuring dopamine concentration and providing electrical stimulation. The developed wireless FSCV system is proven to be a useful experimental tool for the continuous monitoring of dopamine levels during animal learning behavior studies of freely moving rats.

Multidisciplinary rehabilitation following botulinum toxin and other focal intramuscular treatment for post-stroke spasticity

Spasticity may affect stroke survivors by contributing to activity limitations, caregiver burden, pain and reduced quality of life (QoL). Spasticity management guidelines recommend multidisciplinary (MD) rehabilitation programmes following botulinum toxin (BoNT) treatment for post-stroke spasticity.However, the evidence base for the effectiveness of MD rehabilitation is unclear. To assess the effectiveness of MD rehabilitation, following BoNT and other focal intramuscular treatments such as phenol, in improving activity limitations and other outcomes in adults and children with post-stroke spasticity. To explore what settings, types and intensities of rehabilitation programmes are effective. We searched the Cochrane Stroke Group Trials Register (February 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 12), MEDLINE (1948 to December 2011), EMBASE (1980 to January 2012), CINAHL (1982 to January 2012), AMED (1985 to January 2012), LILACS (1982 to September 2012), PEDro, REHABDATA and OpenGrey (September 2012). In an effort to identify further published, unpublished and ongoing trials we searched trials registries and reference lists, handsearched journals and contacted authors. We included randomised controlled trials (RCTs) that compared MD rehabilitation (delivered by two or more disciplines in conjunction with medical input) following BoNT and other focal intramuscular treatments for post-stroke spasticity with placebo, routinely available local services, or lower levels of intervention; or studies that compared MD rehabilitation in different settings, of different types, or at different levels of intensity. We excluded RCTs that assessed the effectiveness of unidisciplinary therapy (for example physiotherapy only) or a single modality (for example stretching, casting, electrical stimulation or splinting only). The primary outcomes were validated measures of activity level (active and passive function) according to the World Health Organization's International Classification of Functioning, Disability and Health. Secondary outcomes included measures of symptoms, impairments, participation, QoL, impact on caregivers and adverse events. We independently selected the trials, extracted data, and assessed methodological quality using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE). Due to the limited number of included studies, with clinical, methodological and statistical heterogeneity, quantitative meta-analysis was not possible. Therefore, GRADE provided qualitative synthesis of 'best evidence'. We included three RCTs involving 91 participants. All three studies scored 'low quality' on the methodological quality assessment, implying high risk of bias.All studies investigated various types and intensities of outpatient rehabilitation programmes following BoNT for upper limb spasticity in adults with chronic stroke. Rehabilitation programmes included: modified constraint-induced movement therapy (mCIMT) compared with a neurodevelopmental therapy programme; task practice therapy with cyclic functional electrical stimulation (FES) compared with task practice therapy only; and occupational, manual therapy with dynamic elbow extension splinting compared with occupational therapy only. There was 'low quality' evidence for mCIMT improving upper limb motor function and spasticity in chronic stroke survivors with residual voluntary upper limb activity, up to six months, and 'very low quality' evidence for dynamic elbow splinting and occupational therapy reducing elbow range of movement at 14 weeks. Task practice therapy with cyclic FES did not improve upper limb function more than task practice therapy alone, only at 12 weeks. No studies addressed interventions in children and those with lower limb spasticity, or after other focal intramuscular treatments for spasticity. At best there was 'low level' evidence for the effectiveness of outpatient MD rehabilitation in improving active function and impairments following BoNT for upper limb spasticity in adults with chronic stroke.No trials explored the effect of MD rehabilitation on 'passive function' (caring for the affected limb), caregiver burden, or the individual's priority goals for treatment. The optimal types (modalities, therapy approaches, settings) and intensities of therapy for improving activity (active and passive function) in adults and children with post-stroke spasticity, in the short and longer term, are unclear. Further research is required to build evidence in this area.

Design and Validation of a Bioreactor for Simulating the Cardiac Niche: A System Incorporating Cyclic Stretch, Electrical Stimulation, and Constant Perfusion

To simulate the cardiac niche, a bioreactor system was designed and constructed to incorporate cyclic stretch, rhythmic electrical stimulation, and constant perfusion. The homogeneity of surface strain distribution across the cell culture substrate was confirmed with ARAMIS deformation analysis. The proliferation marker, Ki-67, detected in human umbilical vein endothelial cells and 3-[4,5-dimethyl-thiazol-2-yl]-2,5-diphenyltetrazolium bromide cytotoxicity assay performed on human atrial fibroblasts confirmed biocompatibility of this novel device. Cyclic stretch treatment for 24 h resulted in the perpendicular alignment of human atrial fibroblasts. An electrical stimulation system containing carbon electrodes was characterized by electrochemical impedance spectroscopy and charge injection/recovery studies, which indicated that increased corrosive reactions were associated with a higher input voltage and prolonged pulse duration. Field stimulation delivered through this system could induce rhythmic contractions in adult rat ventricular myocytes, with contractile characteristics similar to those paced in a standard field stimulation chamber. In conclusion, this bioreactor provides a novel tool to study the interaction between physical stimulation and cardiac cell physiology.

Spinal and Pontine Relay Pathways Mediating Respiratory Rhythm Entrainment by Limb Proprioceptive Inputs in the Neonatal Rat

The coordination of locomotion and respiration is widespread among mammals, although the underlying neural mechanisms are still only partially understood. It was previously found in neonatal rat that cyclic electrical stimulation of spinal cervical and lumbar dorsal roots (DRs) can fully entrain (1:1 coupling) spontaneous respiratory activity expressed by the isolated brainstem/spinal cord. Here, we used a variety of preparations to determine the type of spinal sensory inputs responsible for this respiratory rhythm entrainment, and to establish the extent to which limb movement-activated feedback influences the medullary respiratory networks via direct or relayed ascending pathways. During in vivo overground locomotion, respiratory rhythm slowed and became coupled 1:1 with locomotion. In hindlimb-attached semi-isolated preparations, passive flexion-extension movements applied to a single hindlimb led to entrainment of fictive respiratory rhythmicity recorded in phrenic motoneurons, indicating that the recruitment of limb proprioceptive afferents could participate in the locomotor-respiratory coupling. Furthermore, in correspondence with the regionalization of spinal locomotor rhythm-generating circuitry, the stimulation of DRs at different segmental levels in isolated preparations revealed that cervical and lumbosacral proprioceptive inputs are more effective in this entraining influence than thoracic afferent pathways. Finally, blocking spinal synaptic transmission and using a combination of electrophysiology, calcium imaging and specific brainstem lesioning indicated that the ascending entraining signals from the cervical or lumbar limb afferents are transmitted across first-order synapses, probably monosynaptic, in the spinal cord. They are then conveyed to the brainstem respiratory centers via a brainstem pontine relay located in the parabrachial/Kölliker-Fuse nuclear complex.

Abstract 15: Surface Electrical Stimulation Does Not Improve Hand Function in Subacute Stroke

Background and Objective: Prior studies have suggested that EMG-triggered and cyclic surface electrical stimulation (ES) mediated hand opening exercises facilitate motor recovery of the hemiparetic upper limb. EMG-triggered ES is believed to more effective than cyclic ES due to the addition of cognitive input to trigger the ES. However, these 2 types of ES have not been compared in a placebo controlled randomized clinical trial. This trial tested the hypothesis that EMG-triggered ES is more effective than cyclic ES in facilitating the motor recovery of the hemiparetic upper limb, and that both are more effective than placebo. Methods: Stroke survivors who were within 6-mo of their stroke were randomized to treatment with EMG-triggered ES (EMG), cyclic ES (cyclic) or placebo. The EMG group received the ES by initiating volition finger extension. The resulting EMG from the extensor digitorum communis (EDC) then triggered the ES. The cyclic group received the ES to the EDC in a repetitive timed sequence without volitional activation. For the placebo group, a stimulating electrode was placed on the dorsal forearm away from the motor point of the EDC, and the stimulation intensity was set at sensory threshold with no motor activation. Duty cycle was gradually increased from 5 sec on/20 sec off to 5 sec on/5 sec off as tolerated for all participants. All participants were treated 80 min/day, 5 days a week for 8 weeks. Motor impairment (Fugl-Meyer Motor Assessment-FMA) and activities limitation (Arm Motor Abilities Test-AMAT) outcomes were assessed in a blinded manner at baseline, mid-treatment, end of treatment and at 1, 3 and 6-mo after end of treatment. Data were analyzed using repeated measures ANOVA in an intent-to-treat manner. Results: A total of 122 participants enrolled in the study (EMG: 41; Cyclic: 39; and placebo: 42). Baseline characteristics were comparable between groups. All three groups experienced significant improvement in FMA (F=54.5, p&lt;0.001) and AMAT (F=21.7, p&lt;0.001) scores. However, there were no differences between treatment groups (FMA: F=0.25, p=0.78; AMAT: F=0.43, p=0.55). Conclusions: EMG-triggered and cyclic ES were no more effective than placebo in facilitating the motor recovery of the hemiparetic upper limb. The improvements in FMA and AMAT scores likely represent natural recovery. However, since sensory stimulation without motor activation may not be placebo, the possibility of therapeutic effect of sensory stimulation cannot be ruled out in the present design.

Cervicolumbar Coordination in Mammalian Quadrupedal Locomotion: Role of Spinal Thoracic Circuitry and Limb Sensory Inputs

Effective quadrupedal locomotion requires a close coordination between the spatially distant central pattern generators (CPGs) controlling forelimb and hindlimb movements. Using isolated preparations of the neonatal rat spinal cord, we explore the role of intervening thoracic circuitry in cervicolumbar CPG coordination and the contribution to this remote coupling of limb somatosensory inputs. In preparations activated with bath-applied N-methyl-D,L-aspartate, serotonin, and dopamine, the coordination between locomotor-related bursts recorded in cervical and lumbar ventral roots was substantially weakened, although not abolished, when the thoracic segments were selectively withheld from neurochemical stimulation or were exposed to a low Ca(2+) solution to block synaptic transmission. Moreover, cervicolumbar CPG coordination was reduced after a thoracic midsagittal section, suggesting that cross-cord projections participate in the anteroposterior coupling. In quiescent preparations, either cyclic or tonic electrical stimulation of low-threshold afferent pathways in C8 or L2 dorsal roots (DRs) could elicit coordinated ventral root bursting at both cervical and lumbar levels via an activation of the underlying CPG networks. When lumbar rhythmogenesis was prevented by local synaptic transmission blockade, L2 DR stimulation could still drive left-right alternating cervical bursting in preparations otherwise exposed to normal bathing medium. In contrast, when the cervical generators were selectively blocked, C8 DR stimulation was unable to activate the lumbar CPGs. Thus, in the newborn rat, anteroposterior limb coordination relies on active burst generation within midcord thoracic circuitry that additionally conveys ascending and weaker descending coupling influences of distant limb proprioceptive inputs to the cervical and lumbar generators, respectively.

Mechanostimulation, electrostimulation and force measurement in an in vitro model of the isolated rat diaphragm

In an in vitro model of the entire rat diaphragm, diaphragmatic contraction forces at defined preload levels were investigated. A total of 24 excised rat diaphragms were electrically stimulated inside a two-chamber strain-applicator. The resulting contraction forces were determined on eight adjusted preload levels via measuring the elicited pressure in the chamber below the diaphragm. Subsequently, diaphragms were exposed for 6 h to one of four treatments: (1) control, (2) cyclic mechanical stretch, (3) intermittent electrical stimulation or (4) combination of cyclic mechanical stretch and electrical stimulation. Diaphragmatic contraction force increased from 116 ± 21 mN at the lowest preload level to 775 ± 85 mN at the maximal preload level. After 6 h maximal muscle contraction forces were smallest after non-electrostimulated treatment (control: 81 ± 15 mN, mechanical deflection: 94 ± 12 mN) and largest after electrostimulation treatment (mere electrostimulation: 165 ± 20 mN, combined mechano- and electro-stimulation: 164 ± 14 mN). We conclude that our model allows force measurements on isolated rat diaphragms. Furthermore, we conclude that by intermediate electrical stimulation diaphragmatic force generation was better preserved than by mechanical stimulation.

Combined Bracing, Electrical Stimulation, and Functional Practice for Chronic, Upper-Extremity Spasticity

Conventional methods for managing upper-extremity (UE) spasticity are invasive, usually require readministration after a certain time period, and do not necessarily increase UE function. This study examined efficacy of combining two singularly efficacious modalities-UE bracing and electrical stimulation-with functional training to reduce UE spasticity and improve function. Two chronic stroke patients exhibiting UE spasticity were administered the Modified Ashworth Scale (MAS), the upper-extremity section of the Fugl-Meyer Impairment Scale (FM), the Box and Block Test (B&B), and the Arm Motor Ability Test (AMAT). They were then individually fitted for a brace and subsequently participated in treatment sessions occurring 2 days/wk for 5 wk, consisting of (1) 30-min clinical sessions, during which the UE was braced in a functional position while cyclic electrical stimulation was applied to the antagonist extensors of the tricep and forearm, and (2) 15-min, clinically based training sessions, occurring directly after the clinical session. After intervention, participants exhibited 1-point reductions in MAS scores for the affected fingers, FM score increases, and increased ability to perform AMAT activities,. Three months later, both participants retained these changes. Data point to a noninvasive, promising method of managing spasticity and rendering functional changes.

Cyclic Functional Electrical Stimulation Does Not Enhance Gains in Hand Grasp Function When Used as an Adjunct to OnabotulinumtoxinA and Task Practice Therapy: A Single-Blind, Randomized Controlled Pilot Study

Weber DJ, Skidmore ER, Niyonkuru C, Chang C-L, Huber LM, Munin MC. Cyclic functional electrical stimulation does not enhance gains in hand grasp function when used as an adjunct to onabotulinumtoxinA and task practice therapy: a single-blind, randomized controlled pilot study. Objective To determine whether onabotulinumtoxinA injections and task practice training with or without functional electrical stimulation (FES) improve upper limb motor function in chronic spastic hemiparesis. Design Randomized controlled trial. Setting Outpatient spasticity clinic. Participants Participants (N=23) had chronic spastic hemiparesis with moderate-severe hand impairment based on Chedoke-McMaster Assessment greater than or equal to 2. Interventions OnabotulinumtoxinA injections followed by 12 weeks of postinjection task practice. Participants randomly assigned to FES group were also fitted with an orthosis that provided FES. Main Outcome Measures Motor Activity Log (MAL)–Observation was the primary outcome. Secondary outcomes were Action Research Arm Test (ARAT) and MAL-Self-Report. Results For the entire cohort, MAL-Observation mean item scores improved significantly from baseline to week 6 ( P=.005) but did not remain significant at week 12. MAL-Self-Report mean item scores improved significantly ( P=.009) from baseline to week 6 and remained significantly higher ( P=.014) at week 12. ARAT total scores also improved significantly from baseline to week 6 ( P=.018) and were sustained at week 12 ( P=.032). However, there were no significant differences between the FES and no-FES groups for any outcome variable over time. Conclusions Rehabilitation strategies that combine onabotulinumtoxinA injections and task practice therapy are feasible and effective in improving upper-limb motor function and reducing spasticity in patients with chronic spastic hemiparesis. However, the cyclic FES protocol used in this study did not increase gains achieved with the combination of onabotulinumtoxinA and task practice alone.

Electrical stimulation of the upper extremity in stroke: cyclic versus EMG-triggered stimulation

Objective: To compare the effect of cyclic and electromyography (EMG)-triggered electrical stimulation on motor impairment and function of the affected upper extremity in chronic stroke. Design: Randomized controlled trial. Setting: Outpatient clinic of a rehabilitation centre. Subjects and intervention: Twenty-two subjects in the chronic stage after stroke were randomly assigned to receive either cyclic (n = 11) or EMG-triggered electrical stimulation (n = 11) of the wrist and finger extensor muscles for a six-week period. Outcome measures: The primary outcome measure was the Action Research Arm test (0—57 points) to assess arm function. Grip strength, Fugl-Meyer Motor Assessment and Motricity Index were secondary outcome measures. Assessments were made at the start of the treatment and after 4, 6 and 12 weeks. Results: Both groups improved on the Action Research Arm test. The group receiving cyclic stimulation improved by 2.3 points, and the group receiving EMG-triggered stimulation improved by 4.2 points. The difference in functional gain was not statistically significant. Differences in gain on the secondary outcome measures were not significant either. Conclusion: The present study did not detect a significant difference between EMG-triggered and cyclic electrical stimulation with respect to improvement of motor function of the affected arm in chronic stroke.

Magnetic Resonance Imaging of Morphological and Functional Changes of the Uterus Induced by Sacral Surface Electrical Stimulation

The purpose of this study is to examine the morphological and kinematical changes of the uterus induced by electrical stimulation applied to the skin just above the second and fourth posterior sacral foramens (sacral surface electrical stimulation [ssES]) in 26 healthy subjects. Out of them, eight subjects who had severe pain subjectively during every menstruation received ssES just in menstruation. Morphological and functional changes of the uterus were examined by using T2-weighted magnetic resonance (MR) imaging and T1-weighted MR cinematography, respectively. Cyclic electrical stimulation for 15 min with 5 sec ON and 5 sec OFF was applied just before MR scanning. A decrease in thickness of the muscular layer of the uterus was observed in every subject after ssES for 15 min and was significant as compared with the thickness before ssES. Periodic uterine movement during menstruation was observed in the subjects with severe menstrual pain in MR cine and the power spectrum analysis of the movement showed a marked decrease in peak power and frequency after ssES treatment. We conclude that ssES causes a reduction of static muscle tension of the uterus in all menstrual cycle periods and suppression of uterine peristalsis during menstruation in the subjects with severe menstrual pain. Possible neural mechanisms for these static and dynamic effects of ssES on the uterus at spinal level are discussed.

What is the Ideal Pulse Frequency for Skeletal Muscle Stimulation After Cardiomyoplasty?

Routinely the latissimus dorsi (LD) muscle is stimulated with bursts of pulses at 30 pulses/sec after cardiomyoplasty to assist the failing heart. At a lower pulse frequency the contractile force decreases and at higher frequencies the energy demand of the pacemaker increases rapidly. We investigated the effect of the stimulus frequency variation on contractile force in untrained LD muscles and in muscles after 12 weeks of continuous cyclic electrical stimulation. In six dogs, two electrodes (Medtronic SP5528) were implanted in the left LD muscle together with an Itrel muscle stimulator. The LD muscle was stimulated with 30 pulses/sec in bursts to deliver initially 30 and after 10 weeks 80 contractions per minute. Both before and after training of the LD muscle maximum force was observed by stimulating with a frequency of 36 to 130 pulses/sec in a burst. However, training induced a shift in the steep part of the force-frequency relation to lower frequencies. In particular, at 15 pulses/sec 60% of the maximal force was obtained in contrast to 40% before training. A fatigue test of 8 minutes duration was performed specified by 100 bursts/min and a burst duration of 0.25 sec at pulse frequencies of 30, 36, 50, and 85 pulses/sec. The contractile force decreased significantly during the course of the test at all frequencies. However, the force obtained with 30 pulses/sec stimulation was lower during the initial phase and approximately 10% higher at the end of the fatigue test as compared to 36, 50, and 85 pulses/sec stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)