The effect of long-term TENS on persistent neuroplastic changes in the human cerebral cortex

Tibial nerve stimulation in the management of primary sexual dysfunction in patients with multiple sclerosis: a pilot randomized control trial

INTRODUCTION

Sexual dysfunction (SD) is a common symptom that affects 40-90% of patients with multiple sclerosis (MS). Previous studies have highlighted the negative impact of sexual dysfunction in the mental health status and overall quality of life in patients with MS.

METHODS

The aim of this study was to examine the effects of transcutaneous tibial nerve stimulation (TTNS) in the primary SD symptoms in patients with MS. A total of 40 participants were randomized (1:1 ratio) to either TTNS or Sham group and received three 20 min sessions over the course of two months. Pre and post intervention SD was evaluated using the Multiple Sclerosis Intimacy Questionnaire (MISQ-15).

RESULTS

Statistically significant improvements in the aspects of primary sexual dysfunction were observed in the TTNS group pre-post intervention (specifically erectile function (for males)/vaginal lubrication (for females) (p < .001), orgasm quality and satisfaction for both male and female patients (p < .001), sexual desire (p < .05) and bladder related symptomatology (p < .005). In the sham group pre-post intervention, the only observed improvement was in the sexual desire aspect (p < .05). Post intervention the groups significantly differed erectile function/vaginal lubrication and orgasm quality and satisfaction (p < .05).

CONCLUSIONS

Our findings underline the efficacy of TTNS in improving primary SD symptoms as well as bladder problems in both male and female patients with MS. TTNS demonstrated significant improvement in the following domains: erectile function, vaginal lubrication, orgasm quality, satisfaction, bladder-related symptoms, and sexual desire.

Effects of combined treatment with transcranial and peripheral electromagnetic stimulation on performance and pain recovery from delayed onset muscle soreness induced by eccentric exercise in young athletes. A randomized clinical trial

Background: There is a common interest in finding a common consensus in the approach of athletes suffering from DOMS with the aim of accelerating recovery and thereby enhancing performance. The objective of this study was to observe the effects of a paired-associative transcranial and peripheral electromagnetic stimulation on young athletes suffering from DOMS, induced by 1 h of eccentric and plyometric exercises. Methods: Forty-eight young athletes participated in this randomized control trial: 13 were assigned to the peripheral group (P); 12 were in the control group (Cont); 11 were assigned to the transcranial group (T) and 12 were included in the paired-associative group (Comb). The Visual Analogue Scale (VAS) of pain perception and the mechanical Pressure Pain Threshold (PPT) were the tools used to analyze the symptoms of DOMS. On the other hand, the Half Squat (HS) test evaluated with an accelerometer, and the 30 m sprint velocity (30-mSP) test were used to observe the evolution of the sports performance of the lower limbs. All evaluations were performed before and after the eccentric exercise session that caused DOMS, as well as at 24-48, and 72 h afterward. Results: The AS group improved the symptoms of the induced DOMS, since significant positive differences were observed in the VAS and PPT compared to the other groups (p < 0.001). In addition, the AS group showed a significant improvement in the HS and the 30-mSP tests (p < 0.001). Based on the results a treatment with both peripheral and transcranial electromagnetic stimulation improves recovery and performance in athletes at 72 h, although these data would need to be verified in future research with a larger sample size. Conclusion: Paired-associative electromagnetic stimulation improved DOMS symptomatology, velocity, and sports performance in the lower limbs.

Effectiveness of motor and prefrontal cortical areas for brain-controlled functional electrical stimulation neuromodulation

Objective. Brain-computer interface (BCI)-controlled functional electrical stimulation (FES) could excite the central nervous system to enhance upper limb motor recovery. Our current study assessed the effectiveness of motor and prefrontal cortical activity-based BCI-FES to help elucidate the underlying neuromodulation mechanisms of this neurorehabilitation approach.Approach. The primary motor cortex (M1) and prefrontal cortex (PFC) BCI-FES interventions were performed for 25 min on separate days with twelve non-disabled participants. During the interventions, a single electrode from the contralateral M1 or PFC was used to detect event-related desynchronization (ERD) in the calibrated frequency range. If the BCI system detected ERD within 15 s of motor imagery, FES activated wrist extensor muscles. Otherwise, if the BCI system did not detect ERD within 15 s, a subsequent trial was initiated without FES. To evaluate neuromodulation effects, corticospinal excitability was assessed using single-pulse transcranial magnetic stimulation, and cortical excitability was assessed by motor imagery ERD and resting-state functional connectivity before, immediately, 30 min, and 60 min after each intervention.Main results. M1 and PFC BCI-FES interventions had similar success rates of approximately 80%, while the M1 intervention was faster in detecting ERD activity. Consequently, only the M1 intervention effectively elicited corticospinal excitability changes for at least 60 min around the targeted cortical area in the M1, suggesting a degree of spatial localization. However, cortical excitability measures did not indicate changes after either M1 or PFC BCI-FES.Significance. Neural mechanisms underlying the effectiveness of BCI-FES neuromodulation may be attributed to the M1 direct corticospinal projections and/or the closer timing between ERD detection and FES, which likely enhanced Hebbian-like plasticity by synchronizing cortical activation detected by the BCI system with the sensory nerve activation and movement related reafference elicited by FES.

Top-down and bottom-up stimulation techniques combined with action observation treatment in stroke rehabilitation: a perspective

Stroke is a central nervous system disease that causes structural lesions and functional impairments of the brain, resulting in varying types, and degrees of dysfunction. The bimodal balance-recovery model (interhemispheric competition model and vicariation model) has been proposed as the mechanism of functional recovery after a stroke. We analyzed how combinations of motor observation treatment approaches, transcranial electrical (TES) or magnetic (TMS) stimulation and peripheral electrical (PES) or magnetic (PMS) stimulation techniques can be taken as accessorial physical therapy methods on symptom reduction of stroke patients. We suggest that top-down and bottom-up stimulation techniques combined with action observation treatment synergistically might develop into valuable physical therapy strategies in neurorehabilitation after stroke. We explored how TES or TMS intervention over the contralesional hemisphere or the lesioned hemisphere combined with PES or PMS of the paretic limbs during motor observation followed by action execution have super-additive effects to potentiate the effect of conventional treatment in stroke patients. The proposed paradigm could be an innovative and adjunctive approach to potentiate the effect of conventional rehabilitation treatment, especially for those patients with severe motor deficits.

Effects of peripheral electromagnetic stimulation after an eccentric exercise-induced delayed-onset muscle soreness protocol in professional soccer players: a randomized controlled trial

Introduction: To examine the effects of peripheral electromagnetic stimulation in male professional soccer players on markers of Delayed Onset Muscular Soreness (DOMS), induced by a protocol of exercise (60 min of eccentric and plyometric). Methods: A randomized controlled trial with fourty-five professional soccer players aged 22.33 ± 4.82 years participated in the study. Twenty-three participants were assigned to the experimental group with peripheral electromagnetic stimulation (5 stimulations of 5 s at 100 HZ with 55 s of rest for a total of 5 min of treatment) and the remaining 22 participants were assigned to the control group. Pain pressure threshold (PPT) of the vastus medialis, the Visual Analogue Scale-Fatigue (VAS-F), half squat (HS) test and the maximum voluntary contraction of the quadriceps were assessed. All evaluations were performed before and after 1 h of the eccentric exercise induced DOMS, as well as at post 24-48, and 72 h. Results: Group-by-time interaction was observed in PPT of the vastus medialis (p = 0.040) with a medium effect size (η² p = 0.069). From 48 to 72 h the experimental group showed an increase of PPT compared to control group (p = 0.015). There was no group-by-time interaction for HS, quadriceps strength and VAS-F (p > 0.05). Discussion: Peripheral electromagnetic stimulation in male professional soccer players did not produce significant improvements in the power and strength of the lower limbs but decreased the peripheral sensitization of the vastus medialis after eccentric exercise protocol. Clinical Trial Registration: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=384050&isReview=true, Identifier: ACTRN12622000841774.

Effects of Paired Associative Stimulation on Cortical Plasticity in Agonist–Antagonist Muscle Representations

Paired associative stimulation (PAS) increases and decreases cortical excitability in primary motor cortex (M1) neurons, depending on the spike timing-dependent plasticity, i.e., long-term potentiation (LTP)- and long-term depression (LTD)-like plasticity, respectively. However, how PAS affects the cortical circuits for the agonist and antagonist muscles of M1 is unclear. Here, we investigated the changes in the LTP- and LTD-like plasticity for agonist and antagonist muscles during PAS: 200 pairs of 0.25-Hz peripheral electric stimulation of the right median nerve at the wrist, followed by a transcranial magnetic stimulation of the left M1 with an interstimulus interval of 25 ms (PAS-25 ms) and 10 ms (PAS-10 ms). The unconditioned motor evoked potential amplitudes of the agonist muscles were larger after PAS-25 ms than after PAS-10 ms, while those of the antagonist muscles were smaller after PAS-25 ms than after PAS-10 ms. The γ-aminobutyric acid A (GABAA)- and GABAB-mediated cortical inhibition for the agonist and antagonist muscles were higher after PAS-25 ms than after PAS-10 ms. The cortical excitability for the agonist and antagonist muscles reciprocally and topographically increased and decreased after PAS, respectively; however, GABAA and GABAB-mediated cortical inhibitory functions for the agonist and antagonist muscles were less topographically decreased after PAS-10 ms. Thus, PAS-25 ms and PAS-10 ms differentially affect the LTP- and LTD-like plasticity in agonist and antagonist muscles.

No evidence for a difference in lateralization and distinctiveness level of transcranial magnetic stimulation-derived cortical motor representations over the adult lifespan

This study aimed to investigate the presence and patterns of age-related differences in TMS-based measures of lateralization and distinctiveness of the cortical motor representations of two different hand muscles. In a sample of seventy-three right-handed healthy participants over the adult lifespan, the first dorsal interosseus (FDI) and abductor digiti minimi (ADM) cortical motor representations of both hemispheres were acquired using transcranial magnetic stimulation (TMS). In addition, dexterity and maximum force levels were measured. Lateralization quotients were calculated for homolog behavioral and TMS measures, whereas the distinctiveness between the FDI and ADM representation within one hemisphere was quantified by the center of gravity (CoG) distance and cosine similarity. The presence and patterns of age-related changes were examined using linear, polynomial, and piecewise linear regression. No age-related differences could be identified for the lateralization quotient of behavior or cortical motor representations of both intrinsic hand muscles. Furthermore, no evidence for a change in the distinctiveness of the FDI and ADM representation with advancing age was found. In conclusion this work showed that lateralization and distinctiveness of cortical motor representations, as determined by means of TMS-based measures, remain stable over the adult lifespan.

Hybrid robot-assisted gait training for motor function in subacute stroke: a single-blind randomized controlled trial

Background

Robot-assisted gait training (RAGT) is a practical treatment that can complement conventional rehabilitation by providing high-intensity repetitive training for patients with stroke. RAGT systems are usually either of the end-effector or exoskeleton types. We developed a novel hybrid RAGT system that leverages the advantages of both types.

Objective

This single-blind randomized controlled trial evaluated the beneficial effects of the novel RAGT system both immediately after the intervention and at the 3-month follow-up in nonambulatory patients with subacute stroke.

Methods

We recruited 40 patients with subacute stroke who were equally randomized to receive conventional rehabilitation either alone or with the addition of 15 RAGT sessions. We assessed lower-extremity motor function, balance, and gait performance by using the following tools: active range of motion (AROM), manual muscle test (MMT), the Fugl–Meyer Assessment (FMA) lower-extremity subscale (FMA-LE) and total (FMA-total), Postural Assessment Scale for Stroke (PASS), Berg Balance Scale (BBS), Tinetti Performance-Oriented Mobility Assessment (POMA) balance and gait subscores, and the 3-m and 6-m walking speed and Timed Up and Go (TUG) tests. These measurements were performed before and after the intervention and at the 3-month follow-up.

Results

Both groups demonstrated significant within-group changes in the AROM, MMT, FMA-LE, FMA-total, PASS, BBS, POMA, TUG, and 3-m and 6-m walking speed tests before and after intervention and at the 3-month follow-up (p < 0.05). The RAGT group significantly outperformed the control group only in the FMA-LE (p = 0.014) and total (p = 0.002) assessments.

Conclusion

Although the novel hybrid RAGT is effective, strong evidence supporting its clinical effectiveness relative to controls in those with substantial leg dysfunction after stroke remains elusive.

Trial registration The study was registered with an International Standard Randomized Controlled Trial Number, ISRCTN, ISRCTN15088682. Registered retrospectively on September 16, 2016, at https://www.isrctn.com/ISRCTN15088682

Neuroplasticity after upper-extremity rehabilitation therapy with sensory stimulation in chronic stroke survivors

This study investigated the effect of using subthreshold vibration as a peripheral sensory stimulation during therapy on cortical activity. Secondary analysis of a pilot triple-blinded randomized controlled trial. Twelve chronic stroke survivors underwent 2-week upper-extremity task-practice therapy. Half received subthreshold vibratory stimulation on their paretic wrist (treatment group) and the other half did not (control). EEG connectivity and event-related de-/resynchronization for the sensorimotor network during hand grip were examined at pre-intervention, post-intervention and follow-up. Statistically significant group by time interactions were observed for both connectivity and event-related spectral perturbation. For the treatment group, connectivity increased at post-intervention and decreased at follow-up. Event-related desynchronization decreased and event-related resynchronization increased at post-intervention, which was maintained at follow-up. The control group had the opposite trend for connectivity and no change in event-related spectral perturbation. The stimulation altered cortical sensorimotor activity. The findings complement the clinical results of the trial in which the treatment group significantly improved gross manual dexterity while the control group did not. Increased connectivity in the treatment group may indicate neuroplasticity for motor learning, while reduced event-related desynchronization and increased event-related resynchronization may indicate lessened effort for grip and improved inhibitory control. EEG may improve understanding of neural processes underlying motor recovery.

Concomitant sensory stimulation during therapy to enhance hand functional recovery post stroke

Background

Post-stroke hand impairment is prevalent and persistent even after a full course of rehabilitation. Hand diminishes stroke survivors’ abilities for activities of daily living and independence. One way to improve treatment efficacy is to augment therapy with peripheral sensory stimulation. Recently, a novel sensory stimulation, TheraBracelet, has been developed in which imperceptible vibration is applied during task practice through a wrist-worn device. The objective of this trial is to determine if combining TheraBracelet with hand task practice is superior to hand task practice alone.

Methods

A double-blind randomized controlled trial will be used. Chronic stroke survivors will undergo a standardized hand task practice therapy program (3 days/week for 6 weeks) while wearing a device on the paretic wrist. The device will deliver TheraBracelet vibration for the treatment group and no vibration for the control group. The primary outcome is hand function measured by the Wolf Motor Function Test. Other outcomes include the Box and Block Test, Action Research Arm Test, upper extremity use in daily living, biomechanical measure of the sensorimotor grip control, and EEG-based neural communication.

Discussion

This research will determine clinical utility of TheraBracelet to guide future translation. The TheraBracelet stimulation is delivered via a wrist-worn device, does not interfere with hand motion, and can be easily integrated into clinical practice. Enhancing hand function should substantially increase stroke survivors' independence and quality of life and reduce caregiver burden.

Trial registration

NCT04569123. Registered on September 29, 2020

The effect of transcutaneous electric nerve stimulation on chronic postoperative pain and long-term quality of life

BACKGROUND

This study aims to investigate the effects of transcutaneous electrical nerve stimulation on early-stage postoperative pain and long-term quality of life in patients undergoing thoracotomy.

METHODS

Between January 2019 and September 2019, a total of 100 patients (76 males, 24 females; mean age: 57.9±11.9 years; range, 51 to 79 years) who underwent thoracotomy due to benign or malignant lesions were included. The patients were divided into two groups: 50 patients who received transcutaneous electrical nerve stimulation (Group 1) and a control group of 50 patients who did not receive transcutaneous electrical nerve stimulation (Group 2). The Short Form-36 life quality scale was used to evaluate patients' quality of life at one month before and after surgery.

RESULTS

The mean length of hospital stay was 4.9±3.1 days in Group 1 and 6.2±4.6 days in Group 2 (p=0.008). There were no statistically significant differences in early-stage postoperative pain scores between the groups (p>0.05). Compared to Group 2, Group 1 had significantly lower pain scores and higher life quality scores pre- and postoperatively (p<0.05).

CONCLUSION

Transcutaneous electrical nerve stimulation is an effective method to manage chronic pain in the postoperative period. On the other hand, it does not effectively reduce early-stage postoperative pain or affect complication rates. The prevention of chronic postoperative pain by transcutaneous electrical nerve stimulation improves long-term quality of life of patients.

A study on the immediate effects of neuromuscular electrical stimulation on the corticospinal tract excitability of the infraspinatus muscle

BACKGROUND

Rotator cuff muscles are structurally and functionally different from other upper-limb muscles because they are responsible for glenohumeral joint stability. Neuromuscular electrical stimulation (NMES) induces excitability changes (increase or decrease) of the corticospinal tract (CST) in the peripheral muscles, such as those of the finger. However, it remains unclear whether similar results are obtained when targeting the infraspinatus muscle, which has properties that differ from other muscles, in healthy subjects.

OBJECTIVE

We investigated the immediate effects of NMES on the corticospinal excitability of the infraspinatus muscle, a rotator cuff muscle, in healthy subjects.

METHODS

Thirteen healthy right-handed men (mean age: 26.77 ± 2.08 years) participated in this study. The motor evoked potentials (MEPs) and the maximum compound muscle action potential (Mmax) were recorded before NMES to the right infraspinatus and within 15 minutes after the end of the NMES.

RESULTS

NMES on the infraspinatus muscle significantly increased its MEP amplitude (Pre: 0.45 mV [0.33-0.48]; Post: 0.54 mV [0.46-0.60] (median [lower quartile to higher quartile]); p= 0.005) but had no effect on Mmax (Pre: 2.95 mV [2.59-4.71]; Post: 3.35 mV [2.76-4.72]; p= 0.753).

CONCLUSIONS

NMES application to the infraspinatus muscle increases CST excitability without producing immediate changes in the neuromuscular junction or muscle hypertrophy.

Does non-implanted electrical stimulation reduce post-stroke urinary or fecal incontinence? A systematic review with meta-analysis

BACKGROUND

Urinary and fecal incontinence are disabling impairments after stroke that can be clinically managed with electrical stimulation.

AIM

The purpose of this systematic review was to determine the effectiveness of non-implanted electrical stimulation to reduce the severity of post-stroke incontinence.

SUMMARY OF REVIEW

Clinical trials of non-implanted electrical stimulation applied for the purposes of treating post-stroke incontinence were searched in MEDLINE, EMBASE, CINAHL, PEDro, and CENTRAL. From a total of 5043 manuscripts, 10 trials met the eligibility criteria (n = 894 subjects). Nine trials reported urinary incontinence severity outcomes enabling meta-analysis of transcutaneous electrical nerve stimulation (TENS; five trials) and electroacupuncture (four trials). Studies provide good-to-fair quality evidence that TENS commenced <3 months post-stroke has a large effect on urinary continence (SMD = -3.40, 95% CI -4.46 to -2.34) and a medium effect when commenced >3 months after stroke (SMD = -0.67, 95% CI -1.09 to -0.26). Electroacupuncture has a large effect when administered >5 times a week (SMD = -2.32, 95% CI -2.96 to -1.68) and a small effect when administered five times a week (SMD = -0.44, 95% CI -0.69 to -0.18). Only one trial reported the effect of non-implanted electrical stimulation on post-stroke fecal incontinence.

CONCLUSIONS

Published trials evaluating the effect of non-implanted electrical stimulation on post-stroke incontinence are few and heterogenous. Synthesized trials suggest that early and frequent treatment using electrical stimulation is probably more effective than sham or no treatment. Further trials measuring incontinence in an objective manner are required.

Electroacupuncture-Induced Plasticity between Different Representations in Human Motor Cortex

Somatosensory stimulation can effectively induce plasticity in the motor cortex representation of the stimulated body part. Specific interactions have been reported between different representations within the primary motor cortex. However, studies evaluating somatosensory stimulation-induced plasticity between different representations within the primary motor cortex are sparse. The purpose of this study was to investigate the effect of somatosensory stimulation on the modulation of plasticity between different representations within the primary motor cortex. Twelve healthy volunteers received both electroacupuncture (EA) and sham EA at the TE5 acupoint (located on the forearm). Plasticity changes in different representations, including the map volume, map area, and centre of gravity (COG) were evaluated by transcranial magnetic stimulation (TMS) before and after the intervention. EA significantly increased the map volume of the forearm and hand representations compared to those of sham EA and significantly reduced the map volume of the face representation compared to that before EA. No significant change was found in the map volume of the upper arm and leg representations after EA, and likewise, no significant changes in map area and COG were observed. These results suggest that EA functions as a form of somatosensory stimulation to effectively induce plasticity between different representations within the primary motor cortex, which may be related to the extensive horizontal intrinsic connectivity between different representations. The cortical plasticity induced by somatosensory stimulation might be purposefully used to modulate human cortical function.

Alterations of hand sensorimotor function and cortical motor representations over the adult lifespan

Using a cross sectional design, we aimed to identify the effect of aging on sensorimotor function and cortical motor representations of two intrinsic hand muscles, as well as the course and timing of those changes. Furthermore, the link between cortical motor representations, sensorimotor function, and intracortical inhibition and facilitation was investigated. Seventy-seven participants over the full adult lifespan were enrolled. For the first dorsal interosseus (FDI) and abductor digiti minimi (ADM) muscle, cortical motor representations, GABAA-mediated short-interval intracortical inhibition (SICI), and glutamate-mediated intracortical facilitation (ICF) were assessed using transcranial magnetic stimulation over the dominant primary motor cortex. Additionally, participants' dexterity and force were measured. Linear, polynomial, and piecewise linear regression analyses were conducted to identify the course and timing of age-related differences. Our results demonstrated variation in sensorimotor function over the lifespan, with a marked decline starting around the mid-thirties. Furthermore, an age-related reduction in cortical motor representation volume and maximal MEP of the FDI, but not for ADM, was observed, occurring mainly until the mid-forties. Area of the cortical motor representation did not change with advancing age. Furthermore, cortical motor representations, sensorimotor function, and measures of intracortical inhibition and facilitation were not interrelated.

Combining Transcranial Direct Current Stimulation and Transcutaneous Electrical Nerve Stimulation to Relieve Persistent Pain in a Patient Suffering from Complex Regional Pain Syndrome: A Case Report

PURPOSE

Complex regional pain syndrome (CRPS) is a rare neuropathic pain condition characterized by sensory, motor and autonomic alterations. Previous investigations have shown that transcranial direct current stimulation (tDCS) and transcutaneous electrical nerve stimulation (TENS) can alleviate pain in various populations, and that a combination of these treatments could provide greater hypoalgesic effects. In the present case report, we describe the effect of tDCS and TENS treatment on pain intensity and unpleasantness in a patient suffering from chronic CRPS.

RESULTS

The patient was a 37-year-old woman, suffering from left lower limb CRPS (type I) for more than 5 years. Despite medication (pregabalin, tapentadol, duloxetine), rehabilitation treatments (sensorimotor retraining, graded motor imagery) and spinal cord stimulation (SCS), the participant reported moderate to severe pain. Treatments of tDCS alone (performed with SCS turned off during tDCS application, 1 session/day, for 5 consecutive days) did not significantly decrease pain. Combining tDCS with TENS (SCS temporarily turned off during tDCS, 1 session/day, for 5 consecutive days) slightly reduced pain intensity and unpleasantness.

DISCUSSION

Our results suggest that combining tDCS and TENS could be a therapeutic strategy worth investigating further to relieve pain in chronic CRPS patients. Future studies should examine the efficacy of combined tDCS and TENS treatments in CRPS patients, and other chronic pain conditions, with special attention to the cumulative and long-term effects and its effect on function and quality of life.

Differential Effect of Visual and Proprioceptive Stimulation on Corticospinal Output for Reciprocal Muscles

This study investigated the corticospinal excitability of reciprocal muscles during tasks involving sensory difference between proprioceptive and visual inputs. Participants were instructed to relax their muscles and to observe a screen during vibratory stimulation. A video screen was placed on the board covering the right hand and forearm. Participants were randomly tested in four conditions: resting, control, static, and dynamic. The resting condition involved showing a black screen, the control condition, a mosaic patterned static videoclip; the static condition, a static videoclip of wrist flexion 0°; and the dynamic condition, a videoclip that corresponded to each participant's closely-matched illusory wrist flexion angle and speed by vibration. Vibratory stimulation (frequency 80 Hz and duration 4 s) was applied to the distal tendon of the dominant right extensor carpi radialis (ECR) using a tendon vibrator in the control, static, and dynamic conditions. Four seconds after the vibratory stimulation (end of vibration), the primary motor cortex at the midpoint between the centers of gravity of the flexor carpi radialis (FCR) and ECR muscles was stimulated by transcranial magnetic stimulation (TMS). The ECR motor evoked potential (MEP) amplitudes significantly increased in the control condition compared to the resting condition, whereas the FCR MEP amplitudes did not change between the resting and control conditions. In addition, the ECR MEP amplitudes significantly increased in the static condition compared to the dynamic condition. However, the FCR MEP amplitudes significantly increased in the dynamic condition compared to the static condition. These results imply that the difference between visuo-proprioceptive information had an effect on corticospinal excitability for the muscle. In conclusion, we found that proprioceptive and visual information differentially altered the corticospinal excitability of reciprocal muscles.

Phase I Safety Trial: Extended Daily Peripheral Sensory Stimulation Using a Wrist-Worn Vibrator in Stroke Survivors

Peripheral sensory stimulation augments post-stroke upper extremity rehabilitation outcomes. Most sensory stimulations interfere with natural hand tasks and the stimulation duration is limited. We developed TheraBracelet, low-level random-frequency vibration applied via a wristwatch, to enable stimulation during hand tasks and potentially extend stimulation durations. To determine safety of prolonged exposure to TheraBracelet. Single-site double-blind crossover randomized controlled trial. Chronic stroke survivors were instructed to wear a device on the affected wrist for > 8 h/day everyday for 2 months while coming to the laboratory weekly for evaluations, with a 2-week break between each month. The device applied vibration at 60% and 1% of the sensory threshold for the real and sham month, respectively. The order of the real and sham months was randomized/balanced. Adverse events (AEs) were assessed weekly, including worsening of hand sensation, dexterity, grip strength, pain, or spasticity and occurrence of skin irritation or swelling. Device-related AE rates were compared between the real and sham month. Twenty-five participants completed the study. Six participants (24%) experienced mild AEs involving worsened sensory scores that may be related to the intervention with reasonable possibility. Two experienced them in the real stimulation month only, 3 in the sham month only, and 1 in both months. Therefore, less participants experienced device-related AEs in the real than sham month. Daily stimulation using the device for a month is safe for chronic stroke survivors. Future studies examining the efficacy of pairing TheraBracelet with therapy for increasing neurorehabilitation outcomes are a logical next step. Trial registration: NCT03318341.

Sensory Amplitude Electrical Stimulation via Sock Combined With Standing and Mobility Activities Improves Walking Speed in Individuals With Chronic Stroke: A Pilot Study

Objective: To determine if sensory amplitude electrical stimulation (SES) delivered via sock electrode combined with standing and mobility activities improved gait speed, sensation, balance, and participation in chronic stroke. It was hypothesized that SES would enhance the effectiveness of exercise, resulting in reduced impairment and improved function.

Design: Case Series.

Setting: Home-based intervention.

Participants: Thirteen adults (56.5 + 7.84 years old) with chronic stroke (8.21 + 4.36 years post) and hemiparesis completed the study. Participants were community ambulators.

Intervention: Participants completed 6 weeks of self-administered SES delivered via sock electrode concurrent with standing and mobility activities for a minimum of 5 days/week for 30-min, twice daily.

Outcome Measures: Berg Balance Scale (BBS), Stroke Rehabilitation Assessment of Movement—LE subscale (STREAM), 10 Meter Walk Test (10 MWT), Activities-Specific Balance Confidence Scale (ABC), Stroke Impact Scale (SIS), Perceptual Threshold of Electrical Stimulation (PTTES), and Monofilament testing were administered at pre-test, post-test, and 3-month follow up.

Results: Baseline sensory scores and change scores on functional outcomes were analyzed using Pearson Product-Movement Correlation Coefficients, Friedman test, and Linear mixed models. There was a significant change with 10 MWT self-selected pace (Friedman's p = 0.038). Pre-post intervention changes in other outcome measures were not significant. According to the Cohen's effect size classification, there were medium effect sizes for both the STREAM-LE and Monofilaments.

Conclusion: The use of home-based SES via sock electrode combined with standing and mobility activities may contribute to improve gait speed in chronic stroke.

Somatosensory and transcranial direct current stimulation effects on manual dexterity and motor cortex function: A metaplasticity study

BACKGROUND

Non-invasive neuromodulation may provide treatment strategies for neurological deficits affecting movement, such as stroke. For example, weak electrical stimulation applied to the hand by wearing a "mesh glove" (MGS) can transiently increase primary motor cortex (M1) excitability. Conversely, transcranial direct current stimulation with the cathode over M1 (c-tDCS) can decrease corticomotor excitability.

OBJECTIVE/HYPOTHESIS

We applied M1 c-tDCS as a priming adjuvant to MGS and hypothesised metaplastic effects would be apparent in improved motor performance and modulation of M1 inhibitory and facilitatory circuits.

METHODS

Sixteen right-handed neurologically healthy individuals participated in a repeated measures cross-over study; nine minutes of sham- or c-tDCS followed by 30 min of suprasensory threshold MGS. Dexterity of the non-dominant (left) hand was assessed using the grooved pegboard task, and measures of corticomotor excitability, intracortical facilitation, short-latency afferent inhibition (SAI), short-interval intracortical inhibition (SICI), and SAI in the presence of SICI (SAIxSICI), were obtained at baseline, post-tDCS, and 0, 30 and 60 min post-MGS.

RESULTS

There was a greater improvement in grooved pegboard completion times with c-tDCS primed MGS than sham + MGS. There was also more pronounced disinhibition of SAI. However, disinhibition of SAI in the presence of SICI was less and rest motor threshold higher compared to sham + MGS.

CONCLUSIONS

The results indicate a metaplastic modulation of corticomotor excitability with c-tDCS primed MGS. Further studies are warranted to determine how various stimulation approaches can induce metaplastic effects on M1 neuronal circuits to boost functional gains obtained with motor practice.

Use of imperceptible wrist vibration to modulate sensorimotor cortical activity

Peripheral sensory stimulation has been used as a method to stimulate the sensorimotor cortex, with applications in neurorehabilitation. To improve delivery modality and usability, a new stimulation method has been developed in which imperceptible random-frequency vibration is applied to the wrist concurrently during hand activity. The objective of this study was to investigate effects of this new sensory stimulation on the sensorimotor cortex. Healthy adults were studied. In a transcranial magnetic stimulation (TMS) study, resting motor threshold, short-interval intracortical inhibition, and intracortical facilitation for the abductor pollicis brevis muscle were compared between vibration on vs. off, while subjects were at rest. In an electroencephalogram (EEG) study, alpha and beta power during rest and event-related desynchronization (ERD) for hand grip were compared between vibration on vs. off. Results showed that vibration decreased EEG power and decreased TMS short-interval intracortical inhibition (i.e., disinhibition) compared with no vibration at rest. Grip-related ERD was also greater during vibration, compared to no vibration. In conclusion, subthreshold random-frequency wrist vibration affected the release of intracortical inhibition and both resting and grip-related sensorimotor cortical activity. Such effects may have implications in rehabilitation.

TheraBracelet Stimulation During Task-Practice Therapy to Improve Upper Extremity Function After Stroke: A Pilot Randomized Controlled Study

BACKGROUND

Peripheral sensory stimulation has been used in conjunction with upper extremity movement therapy to increase therapy-induced motor gains in patients with stroke. The limitation is that existing sensory stimulation methods typically interfere with natural hand tasks and thus are administered prior to therapy, requiring patients' time commitment. To address this limitation, we developed TheraBracelet. This novel stimulation method provides subthreshold (ie, imperceptible) vibratory stimulation to the wrist and can be used during hand tasks/therapy without interfering with natural hand tasks.

OBJECTIVE

The objective was to determine the feasibility of using TheraBracelet during therapy to augment motor recovery after stroke.

DESIGN

The design was a triple-blinded pilot randomized controlled trial.

METHODS

Twelve chronic stroke survivors were assigned to the treatment or control group. All participants completed 2-hour task practice therapy sessions thrice weekly for 2 weeks. Both groups wore a small vibrator on the paretic wrist, which was turned on to provide TheraBracelet stimulation for the treatment group and turned off for the control group to provide sham stimulation. Outcome measures (Box and Block Test [BBT] and Wolf Motor Function Test [WMFT]) were obtained at baseline, 6 days after therapy, and at follow-up 19 days after therapy.

RESULTS

The intervention was feasible with no adverse events. The treatment group significantly improved their BBT scores after therapy and at follow-up compared with baseline, whereas the control group did not. For WMFT, the group × time interaction was short of achieving significance. Large effect sizes were obtained (BBT d = 1.43, WMFT d = 0.87). No indication of desensitization to TheraBracelet stimulation was observed.

LIMITATIONS

The limitation was a small sample size.

CONCLUSIONS

TheraBracelet could be a promising therapy adjuvant for upper extremity recovery after stroke.

Nonequivalent modulation of corticospinal excitability by positive and negative outcomes

OBJECTIVE

The difference between positive and negative outcomes is important in trial-and-error decision-making processes and affects corticospinal excitability. This study investigated corticospinal excitability during the performance of trial-and-error decision-making tasks with varying competing behavioral outcomes.

METHODS

Each trial began with one of five colored circles presented as a cue. Each color represented a different reward probability, ranging from 10% to 90%. The subjects were instructed to decide whether to perform wrist flexion in response to the cue. Two seconds after the presentation of the cue, a reward stimulus (picture of a coin) or penalty stimulus (mauve circle) was randomly presented to the subject. If the picture of a coin appeared, the subjects received the coin after the experiment if they had performed wrist flexion, but not if they had not performed wrist flexion. If a mauve circle appeared, a coin was deducted from the total reward if the subjects had performed wrist flexion, but not if they had not performed wrist flexion. One second after the reward or penalty stimulus, transcranial magnetic stimulation was delivered to the primary motor cortex at the midpoint between the centers of gravity of the flexor carpi radialis (agonist) and extensor carpi radialis (antagonist) muscles.

RESULTS

Cumulative wrist flexions were positively correlated with reward probabilities. Motor evoked potential (MEP) amplitudes in agonist muscles were significantly higher when wrist flexion incurred a penalty than when it incurred a reward, but there was no difference in the MEP amplitudes of antagonist muscles.

CONCLUSION

Positive and negative behavioral outcomes differentially altered behavior and corticospinal excitability, and unexpected penalties had a stronger effect on corticospinal excitability for agonist muscles.

Addressing Neuroplastic Changes in Distributed Areas of the Nervous System Associated With Chronic Musculoskeletal Disorders

Present interventions utilized in musculoskeletal rehabilitation are guided, in large part, by a biomedical model where peripheral structural injury is believed to be the sole driver of the disorder. There are, however, neurophysiological changes across different areas of the peripheral and central nervous systems, including peripheral receptors, dorsal horn of the spinal cord, brain stem, sensorimotor cortical areas, and the mesolimbic and prefrontal areas associated with chronic musculoskeletal disorders, including chronic low back pain, osteoarthritis, and tendon injuries. These neurophysiological changes appear not only to be a consequence of peripheral structural injury but also to play a part in the pathophysiology of chronic musculoskeletal disorders. Neurophysiological changes are consistent with a biopsychosocial formulation reflecting the underlying mechanisms associated with sensory and motor findings, psychological traits, and perceptual changes associated with chronic musculoskeletal conditions. These changes, therefore, have important implications in the clinical manifestation, pathophysiology, and treatment of chronic musculoskeletal disorders. Musculoskeletal rehabilitation professionals have at their disposal tools to address these neuroplastic changes, including top-down cognitive-based interventions (eg, education, cognitive-behavioral therapy, mindfulness meditation, motor imagery) and bottom-up physical interventions (eg, motor learning, peripheral sensory stimulation, manual therapy) that induce neuroplastic changes across distributed areas of the nervous system and affect outcomes in patients with chronic musculoskeletal disorders. Furthermore, novel approaches such as the use of transcranial direct current stimulation and repetitive transcranial magnetic stimulation may be utilized to help renormalize neurological function. Comprehensive treatment addressing peripheral structural injury as well as neurophysiological changes occurring across distributed areas of the nervous system may help to improve outcomes in patients with chronic musculoskeletal disorders.

Improving arm function in chronic stroke: a pilot study of sensory amplitude electrical stimulation via glove electrode during task-specific training

OBJECTIVE

To investigate the effects of sensory amplitude electrical stimulation (SES) delivered by glove electrode during task-specific exercise on arm movement, function, and sensation in chronic stroke.

METHODS

The design was an intervention pilot study, pre-test, post-test, follow-up design. The settings used were a university research laboratory and home-based intervention. Participants comprised of 11 individuals with chronic stroke (7.2 ± 4.1 years post onset) and moderate arm paresis, 10.82/20 ± 2.27 on the Stroke Rehabilitation Assessment of Movement (STREAM) - Arm Subscale. Participants were seven males and four females (mean age: 59 years). Participants were recruited from university-based database. Intervention- Participants engaged in task-specific training at home for 30 min, twice daily, for 5 weeks, while receiving SES via glove electrode. Participants received supervised task practice at least twice during intervention period for 1 hour. Main outcome measures- Jebsen-Taylor Hand Function Test (JTHFT), STREAM - Arm Subscale, Motor Activity Log-14 (MAL-14) - Amount and Quality Subscales, and Nottingham Stereognosis Assessment (NSA).

RESULTS

Significant changes were found in group mean pre- and post-test comparisons on the NSA (P = 0.042), MAL amount subscale (P = 0.047), and JTHFT (with writing item 29 excluded) (P = 0.003) and in pre-test to follow-up comparisons on NSA (P = 0.027) and JTHFT (writing item excluded) (P = 0.009). There was no significant change on the STREAM (P = 1.0). Individuals with a greater baseline motor capacity determined by STREAM scores (P = 0.048) and more recent stroke (P = 0.014) had significantly greater improvements.

CONCLUSION

Combining task-specific training with glove-based SES in chronic stroke resulted in changes in arm sensation and function that were maintained at 3-month follow-up.

Continuous passive movement does not influence motor maps in healthy adults

Hand weakness following stroke is often associated with a reduced representation of the hand in the primary motor cortex. Meaningful sensory input can induce sensorimotor reorganization in the brain, but the after-effect of continuous passive motion (CPM) on the cortical representation is unknown. The purpose of this study was to determine whether repeated sessions of continuous passive movement of the thumb induce a lasting increase in the motor cortical representation of a thumb muscle in healthy adults. Thirteen right-handed healthy adults (mean age 24.3 ± 4.3 years) participated in the study. Single-pulse Transcranial Magnetic Stimulation (TMS) was delivered over the motor area of the target muscle (abductor pollicis brevis) before and/or after a thirty minute session of thumb CPM administered on three consecutive days. TMS was also delivered 5 days after cessation of the CPM intervention. The response to TMS (motor evoked potential) was recorded in the target muscle with surface EMG. Resting motor threshold (RMT), motor evoked potential amplitude at a specified intensity, and the area and volume of the cortical representation of the target muscle were measured. Thumb CPM had no significant effect on TMS parameters (p > 0.05 all measures) and performance of an attention task remained unchanged within and across CPM sessions. The results suggest that three sessions of repetitive passive thumb movement is not sufficient to induce a change in the cortical representation of the thumb and is unlikely to reverse the decreased representation of the affected hand following stroke.

TMS brain mapping in less than two minutes

BACKGROUND

Transcranial magnetic stimulation (TMS) corticospinal excitability maps are a valuable tool to study plasticity in the corticospinal tract. Traditionally, data acquisition for a single map is time consuming, limiting the method's applicability when excitability changes quickly, such as during motor learning, and in clinical investigations where assessment time is a limiting factor.

OBJECTIVE

To reduce the time needed to create a reliable map by 1) investigating the minimum interstimulus interval (ISI) at which stimuli may be delivered, and 2) investigating the minimum number of stimuli required to create a map.

METHOD

Frameless stereotaxy was used to monitor coil position as the coil was moved pseudorandomly within a 6 × 6 cm square. Maps were acquired using 1-4 s ISIs in 12 participants. The minimum number of stimuli was determined by randomly extracting data and comparing the resulting map to the original data set. To confirm validity, the pseudorandom walk method was compared against a traditional mapping method.

RESULTS

Reliable maps could be created with 63 stimuli recorded with a 1 s ISI. Maps created acquiring data using the pseudorandom walk method were not significantly different from maps acquired following the traditional method.

CONCLUSIONS

To account for inter-participant variability, outliers, coil positioning errors and, most importantly, participant comfort during data acquisition, we recommend creating a map with 80 stimuli and a 1.5 s ISI. This makes it possible to acquire TMS maps in 2 min, making mapping a more feasible tool to study short- and long-term changes in cortical organization.

Cortical vs. afferent stimulation as an adjunct to functional task practice training: a randomized, comparative pilot study in people with cervical spinal cord injury

OBJECTIVE

To assess single-session effects of three different types of stimuli known to increase cortical excitability when combined with functional task practice.

DESIGN

Randomized cross-over trial.

PARTICIPANTS

A total of 24 participants with chronic cervical spinal cord injury.

INTERVENTIONS

One 30-minute session of each, applied concurrently with functional task practice: transcranial direct current stimulation, vibration, and transcutaneous electrical nerve stimulation.

MEASUREMENTS

Nine-hole Peg Test, pinch force, visuomotor tracking, and cortical excitability were collected at pretest, posttest and late posttest (30 minutes after). Early effects (posttest minus pretest) and short-term persistence (late posttest minus pretest) were assessed using a general linear mixed model. Magnitude of effect size was assessed using the Cohen's d.

RESULTS

Transcutaneous electrical nerve stimulation was associated with moderate, significant early effects and short-term persistence on Nine-hole Peg Test performance (1.8 ±1.8, p = 0.003, d = 0.59; 2.0 ±2.5, p < 0.001, Cohen's d = 0.65, respectively). Transcranial direct current stimulation (1.8 ±2.5, p = 0.003, Cohen's d = 0.52) was also associated with significant short-term persistence of moderate size on Nine-hole Peg Test performance (1.8 ±2.5, p = 0.003, Cohen's d = 0.52) and visuomotor tracking performance (p = 0.05, d = 0.51). Early effects on corticomotor excitability were significant for transcutaneous electrical nerve stimulation (p = 0.003), approached significance for transcranial direct current stimulation (p = 0.07), and only vibration was associated with significant short-term persistence (p = 0.006).

CONCLUSIONS

Meaningful improvements in aspects of hand-related function that persisted at least 30 minutes after intervention were observed with transcutaneous electrical nerve stimulation and transcranial direct current stimulation, when combined with functional task practice.

Therapeutic effects of functional electrical stimulation on gait in individuals post-stroke

Functional electrical stimulation (FES) to lower extremity (LE) muscles is used by individuals post-stroke as an alternative to mechanical orthotic devices during gait or as a training modality during rehabilitation. Technological developments which improve the feasibility, accessibility and effectiveness of FES systems as orthotic and training devices, highlight the potential of FES for rehabilitating LE function in individuals post-stroke. This study presents a systematic review of the carryover effects of LE FES to motor performance when stimulation is not applied (therapeutic effects) in subjects post-stroke. A description of advances in FES technologies, with an emphasis on systems designed to promote LE function is included, and mechanisms that may be associated with the observed therapeutic effects are discussed. Eligible studies were reviewed for methodological quality, population, intervention and outcome characteristics. Therapeutic effects of FES were consistently demonstrated at the body function and activity levels when it was used as a training modality. Compared to matched treatments that did not incorporate FES, no definite conclusions can be drawn regarding the superiority of FES. When FES was used as an alternative to an orthotic device, it had no superior therapeutic effects at the activity level, yet patients still seemed to prefer it.

Motor cortex-evoked activity in reciprocal muscles is modulated by reward probability

Horizontal intracortical projections for agonist and antagonist muscles exist in the primary motor cortex (M1), and reward may induce a reinforcement of transmission efficiency of intracortical circuits. We investigated reward-induced change in M1 excitability for agonist and antagonist muscles. Participants were 8 healthy volunteers. Probabilistic reward tasks comprised 3 conditions of 30 trials each: 30 trials contained 10% reward, 30 trials contained 50% reward, and 30 trials contained 90% reward. Each trial began with a cue (red fixation cross), followed by blue circle for 1 s. The subjects were instructed to perform wrist flexion and press a button with the dorsal aspect of middle finger phalanx as quickly as possible in response to disappearance of the blue circle without looking at their hand or the button. Two seconds after the button press, reward/non-reward stimulus was randomly presented for 2-s duration. The reward stimulus was a picture of Japanese 10-yen coin, and each subject received monetary reward at the end of experiment. Subjects were not informed of the reward probabilities. We delivered transcranial magnetic stimulation of the left M1 at the midpoint between center of gravities of agonist flexor carpi radialis (FCR) and antagonist extensor carpi radialis (ECR) muscles at 2 s after the red fixation cross and 1 s after the reward/non-reward stimuli. Relative motor evoked potential (MEP) amplitudes at 2 s after the red fixation cross were significantly higher for 10% reward probability than for 90% reward probability, whereas relative MEP amplitudes at 1 s after reward/non-reward stimuli were significantly higher for 90% reward probability than for 10% and 50% reward probabilities. These results implied that reward could affect the horizontal intracortical projections in M1 for agonist and antagonist muscles, and M1 excitability including the reward-related circuit before and after reward stimulus could be differently altered by reward probability.

Optimization of the transcranial magnetic stimulation protocol by defining a reliable estimate for corticospinal excitability

The goal of this study was to optimize the transcranial magnetic stimulation (TMS) protocol for acquiring a reliable estimate of corticospinal excitability (CSE) using single-pulse TMS. Moreover, the minimal number of stimuli required to obtain a reliable estimate of CSE was investigated. In addition, the effect of two frequently used stimulation intensities [110% relative to the resting motor threshold (rMT) and 120% rMT] and gender was evaluated. Thirty-six healthy young subjects (18 males and 18 females) participated in a double-blind crossover procedure. They received 2 blocks of 40 consecutive TMS stimuli at either 110% rMT or 120% rMT in a randomized order. Based upon our data, we advise that at least 30 consecutive stimuli are required to obtain the most reliable estimate for CSE. Stimulation intensity and gender had no significant influence on CSE estimation. In addition, our results revealed that for subjects with a higher rMT, fewer consecutive stimuli were required to reach a stable estimate of CSE. The current findings can be used to optimize the design of similar TMS experiments.

Induction of cortical plasticity for reciprocal muscles by paired associative stimulation

BACKGROUND

Paired associative stimulation (PAS) is widely used to induce plasticity in the human motor cortex. Although reciprocal inhibition of antagonist muscles plays a fundamental role in human movements, change in cortical circuits for reciprocal muscles by PAS is unknown.

METHODS

We investigated change in cortical plasticity for reciprocal muscles during PAS. PAS consisted of 200 pairs of peripheral electric stimulation of the right median nerve at the wrist at a frequency of 0.25 Hz followed by transcranial magnetic stimulation of the left M1 at the midpoint between the center of gravities of the flexor carpi radialis (FCR) and extensor carpi radialis (ECR) muscles. Measures of motor cortical excitability included resting motor threshold (RMT), GABAA-mediated short-interval intracortical inhibition (SICI), and GABAB-mediated long-interval intracortical inhibition (LICI).

RESULTS

Motor evoked potential amplitude-conditioned LICI for the FCR muscle was significantly decreased after PAS (P = 0.020), whereas that for the ECR muscle was significantly increased (P = 0.033). Changes in RMT and SICI for the FCR and ECR muscles were not significantly different before and after PAS. Corticospinal excitability for both reciprocal muscles was increased during PAS, but GABAB-mediated cortical inhibitory functions for the agonist and antagonist muscles were reciprocally altered after PAS.

CONCLUSION

These results implied that the cortical excitability for reciprocal muscles including GABAB-ergic inhibitory systems within human M1 could be differently altered by PAS.

Effects of practice combined with somatosensory or motor stimulation on hand function in persons with spinal cord injury

BACKGROUND

Individuals with chronic tetraplegia prioritize recovery of hand function as an important factor in improving their quality of life. Interventions that may improve hand function and increase corticomotor excitability are functional electrical stimulation (FES), somatosensory stimulation (SS), and task-oriented training.

OBJECTIVE

We compared functional and corticomotor outcomes in a control condition to changes associated with FES (triggered via electromygraphic signals) and with SS (constant trains), each combined with either unimanual or bimanual training.

METHODS

Using a randomized, clinical trial design, comparisons were made to a delayed intervention control group. Participants (n = 24) had chronic tetraplegia, with the ability to activate thenar muscles, and were randomly assigned to either the immediate intervention (intervention) or control/ delayed intervention groups. Primary analyses compared intervention (FES or SS) to control/delayed intervention. Secondary analyses compared subgroups of FES versus SS (regardless of uni- or bilateral training) and uni- versus bimanual training (regardless of stimulation type). Outcomes were assessed before and after the control and the intervention period.

RESULTS

Compared to control/delayed intervention, the intervention group had greater changes in unimanual function and corticomotor area, regardless of whether practice was combined with FES or with SS. Irrespective of stimulation type, the bimanual subgroups improved to a greater extent than the unimanual subgroups on the bimanual hand function test.

CONCLUSIONS

Hand training combined with either SS or FES was associated with improved hand use and corticomotor activity in persons with chronic tetraplegia. Both interventions appear to be equally effective.

Electrical acupoint stimulation of the affected arm in acute stroke: a placebo-controlled randomized clinical trial

OBJECTIVES

To determine whether adding electrical stimulation of upper limb acupoints to conventional rehabilitation during acute stroke could produce greater and longer lasting motor improvements of the arm.

DESIGN

Double-blind, randomized, placebo-controlled trial.

SETTING

Acute stroke wards, followed by rehabilitation hospitals and subjects' residences.

PARTICIPANTS

Seventy-three patients ≤ 46 hours post stroke onset with moderate to severe weakness in the arm contralateral to the side of stroke.

INTERVENTION

All subjects received conventional rehabilitation. Twenty-nine received additional electrical stimulation, 21 received additional placebo-electrical stimulation and 23 received conventional rehabilitation only, as control. Electrical stimulation or placebo-electrical stimulation was applied to acupoints GB20, LI15, LI11, LI10 and LI4, 60 minutes a day, five days a week, for four weeks.

MEASUREMENTS

Primary outcome measures were hand grip and pinch strength, with Action Research Arm Test (ARAT) as secondary outcome measure. These were assessed on the affected arm at recruitment, then 4 (W4), 12 (W12) and 24 weeks (W24) afterwards.

RESULTS

Post-hoc analysis showed that the electrical stimulation group had greater improvements than the control group in hand grip (P = 0.015) and pinch strength (P = 0.007) at W4, with the gains maintained at W12 and W24. In contrast, the placebo-electrical stimulation group did not differ from either the control or the electrical stimulation group. Between-group improvements in ARAT scores from baseline to W24 (by 16.8 in control, 27.6 in placebo-electrical stimulation group and 26.3 in electrical stimulation group) were not significant.

CONCLUSIONS

Adding four weeks of electrical stimulation during acute stroke appears to produce greater and longer lasting hand grip and pinch strength improvements than administering conventional rehabilitation alone.

Long-term TENS treatment decreases cortical motor representation in multiple sclerosis

This study investigated the effects of a long-term transcutaneous electrical nerve stimulation (TENS) treatment on cortical motor representation in patients with multiple sclerosis (MS). In this double-blind crossover design, patients received either TENS or sham stimulation for 3 weeks (1h per day) on the median nerve region of the most impaired hand, followed by the other stimulation condition after a washout period of 6 months. Cortical motor representation was mapped using transcranial magnetic stimulation (TMS) at the baseline and after the 3-week stimulation protocol. Our results revealed that 3 weeks of daily stimulation with TENS significantly decreased the cortical motor representation of the stimulated muscle in MS patients. Although the mechanisms underlying this decrease remain unclear, our findings indicate that TENS has the ability to induce long-term reorganization in the motor cortex of MS patients.

Manipulation of and sustained effects on the human brain induced by different modalities of acupuncture: an fMRI study

The javascript:void(0)manipulation and sustained effects of acupuncture have been investigated in multiple studies, but several findings are inconsistent with one another. One possible explanation for these discrepancies is that different modalities of acupuncture were utilized in these studies. In the present study, we investigated both the manipulation and sustained effects of acupuncture in different modalities, including manual acupuncture (MA), electroacupuncture (EA) and transcutaneous electrical acupoint stimulation (TEAS). MA, EA, TEAS and sensory control stimulation were applied to 18 healthy subjects, and combined block-designed and resting-state fMRI scans were performed. In analyzing these data, the block-designed datasets were used to assess the manipulation effect by employing a modified general linear model. The data from the resting states, before and after stimulation, were used to explore the brain networks involved in the sustained effect. The results showed that the two 1-min stimulation periods produced similar activation patterns in the sensory control with positive activation in the sensorimotor areas and negative activation in the default mode areas. Although similar patterns could be detected in the first stimulation period in MA, EA and TEAS, no positive activation result was observed in the second stimulation period, and EA showed a more extensive deactivation compared to MA and TEAS. Additionally, all three of the modalities of acupuncture stimulation could increase the instinct brain network in rest. A more secure and spatially extended connectivity of the default mode network was observed following MA and EA, and TEAS specifically increased the functional connectivity in the sensorimotor network. The present study suggested that different brain mechanisms might be recruited in different acupuncture modalities. In addition, the findings from our work could provide methodological information for further research into the mechanism of acupuncture.

The effects of transcutaneous electrical nerve stimulation on strength, proprioception, balance and mobility in people with stroke: a randomized controlled cross-over trial

OBJECTIVE

To investigate the feasibility and potential efficacy of 'activeTENS' (that is transcutaneous electrical nerve stimulation (TENS) during everyday activities) by assessing the immediate effects on strength, proprioception, balance/falls risk and mobility after stroke.

DESIGN

A paired-sample randomized cross-over trial.

SUBJECTS

Twenty-nine mobile chronic stroke survivors with no pre-existing conditions limiting balance or mobility or contra-indications to TENS.

SETTING

University clinical research facility.

INTERVENTION

A single session of 'activeTENS' delivered via a 'sock electrode' (70-130 Hz, five second cycle) plus a session of control treatment (wearing the sock electrode with no stimulation), lasting approximately two hours in total.

MAIN OUTCOMES

Dorsiflexor and plantarflexor strength and proprioception using an isokinetic dyanometer, balance and falls risk (Standing Forward Reach Test) and gait speed (10-m walk test).

RESULTS

All participants tolerated 'active TENS'. Most parameters improved during stimulation with activeTENS; balance (p = 0.009), gait speed (p = 0.002), plantarflexor strength (p = 0.008) and proprioception of plantarflexion (p = 0.029), except dorsiflexor strength (p = 0.194) and dorsiflexion proprioception (p = 0.078).

CONCLUSIONS

The results provide initial evidence of the potential of 'active TENS' to benefit physical function after stroke which warrants further phase II trials to develop the intervention. Concerns that stimulation could have a detrimental impact on balance and increase risk of falls were not supported.

Afferent stimulation provided by glove electrode during task-specific arm exercise following stroke

Background:

Sensory amplitude electrical stimulation (SES) and repetitive task practice reduce impairments and arm dysfunction when delivered separately following stroke.

Objective:

To determine if home-based, task-specific arm exercise was more effective when administered concurrent with SES.

Methods:

Thirty-eight subjects with chronic stroke and mean Fugl-Meyer Assessment (FMA) score 28/66 (15–45) participated. Subjects were randomly assigned to an SES ( n = 20) or sham stimulation ( n = 18) group. Subjects engaged in task-based home exercise for 30 minutes, twice daily, for four weeks while wearing a glove electrode on the impaired hand. Experimental subjects received SES while control subjects received sham stimulation during exercise. Primary outcome measures: FMA and Arm Motor Ability Test (AMAT).

Results:

There were no significant between-group differences for outcome measures. There was a significant difference between the pre- and post-test scores in the SES group AMAT median time ( P = 0.003 95% confidence interval (CI): −14.304, −6.365; effect size: 0.84). Practice time was not associated with changes in outcomes. Subjects with more sensorimotor dysfunction had significantly greater improvements on AMAT median time ( P = 0.037). There was a significant relationship between baseline FMA score and FMA change score ( r = 0.402; P = 0.006).

Conclusions:

This study describes a unique SES delivery system via glove electrode that enabled delivery of SES during home-based arm task practice in stroke survivors. Task practice with concurrent SES did not demonstrate significantly better effects than task practice with sham stimulation, however there was a trend for greater improvement in one activity measure.

Improving human plateaued motor skill with somatic stimulation

Procedural motor learning includes a period when no substantial gain in performance improvement is obtained even with repeated, daily practice. Prompted by the potential benefit of high-frequency transcutaneous electrical stimulation, we examined if the stimulation to the hand reduces redundant motor activity that likely exists in an acquired hand motor skill, so as to further upgrade stable motor performance. Healthy participants were trained until their motor performance of continuously rotating two balls in the palm of their right hand became stable. In the series of experiments, they repeated a trial performing this cyclic rotation as many times as possible in 15 s. In trials where we applied the stimulation to the relaxed thumb before they initiated the task, most reported that their movements became smoother and they could perform the movements at a higher cycle compared to the control trials. This was not possible when the dorsal side of the wrist was stimulated. The performance improvement was associated with reduction of amplitude of finger displacement, which was consistently observed irrespective of the task demands. Importantly, this kinematic change occurred without being noticed by the participants, and their intentional changes of motor strategies (reducing amplitude of finger displacement) never improved the performance. Moreover, the performance never spontaneously improved during one-week training without stimulation, whereas the improvement in association with stimulation was consistently observed across days during training on another week combined with the stimulation. The improved effect obtained in stimulation trials on one day partially carried over to the next day, thereby promoting daily improvement of plateaued performance, which could not be unlocked by the first-week intensive training. This study demonstrated the possibility of effectively improving a plateaued motor skill, and pre-movement somatic stimulation driving this behavioral change.

Does sensory transcutaneous electrical stimulation enhance motor recovery following a stroke? A systematic review

BACKGROUND

Somatosensory input may lead to long-lasting cortical plasticity enhanced by motor recovery in patients with neurological impairments. Sensory transcutaneous electrical stimulation (TENS) is a relatively risk-free and easy-to-implement modality for rehabilitation.

OBJECTIVE

The authors systematically examine the effects of sensory TENS on motor recovery after stroke.

METHODS

Eligible randomized or quasi-randomized trials were identified via searches of computerized databases. Two assessors reviewed independently the eligibility and methodological quality of the retrieved articles.

RESULTS

In all, 15 articles satisfied the inclusion criteria. Methodological quality was generally good, with a mean (standard deviation) PEDro score of 6.7/10 (1.2). Although the majority of studies reported significant effects on at least 1 outcome measure, effect sizes were generally small. Meta-analysis could not be performed for the majority of outcome measures because of variability between studies and insufficient data. A moderate effect was determined for force production of the ankle dorsiflexors and for the Timed Up and Go test.

CONCLUSIONS

Sensory stimulation via TENS may be beneficial to enhance aspects of motor recovery following a stroke, particularly when used in combination with active training. Because of the great variability between studies, particularly in terms of the timing of the intervention after the stroke, the outcome measures used, and the stimulation protocols, insufficient data are available to provide guidelines about strategies and efficacy.

Long-lasting contralateral motor cortex excitability is increased by unilateral hand movement that triggers electrical stimulation of opposite homologous muscles

BACKGROUND/OBJECTIVE

Long-term changes in the motor cortex can be induced by practicing motor tasks with simultaneous application of peripheral nerve stimulation. This combination may augment motor rehabilitation after stroke but has been used primarily during contraction of the affected hand. The authors tested the effect of a right hand movement that electrically stimulated left hand contraction on right motor cortex excitability.

METHODS

Three tasks were used in 15 healthy subjects--a motor and stimulation task (MS(task)), stimulation only task (S(task)), and motor only task (M(task)). The MS(task) consisted of isometric thumb abduction of the right hand that triggered paired electrical stimulation of the left abductor pollicis brevis (APB) and first dorsal interosseus (FDI) motor points. The S(task) was performed 1 week later and matched the stimulation received in the MS(task). The M(task) was performed as a control. Transcranial magnetic stimulation applied to the right motor cortex assessed corticospinal excitability, short latency intracortical inhibition, and intracortical facilitation of the FDI and APB before, immediately after, and 30 minutes after task performance.

RESULTS

Corticospinal excitability increased in the FDI and APB following the MS(task) but not following the S(task) or M(task). The increased excitability present 30 minutes after the MS(task) also correlated with excitability measures recorded 1 week later.

CONCLUSION

A bilateral motor and electrical stimulation task can drive persistent adaptation within the corticospinal system. Hemiplegic subjects who have poor voluntary movement of the affected hand may be able to contract the unaffected hand to activate and train homologous movements.