The neuromodulatory role of dopamine in improved reaction time by acute cardiovascular exercise.

Acute cardiovascular physical exercise improves cognitive performance, as evidenced by a reduction in reaction time (RT). However, the mechanistic understanding of how this occurs is elusive and has not been rigorously investigated in humans. Here, using positron emission tomography (PET) with [11 C]raclopride, in a multi-experiment study we investigated whether acute exercise releases endogenous dopamine (DA) in the brain. We hypothesized that acute exercise augments the brain DA system, and that RT improvement is correlated with this endogenous DA release. The PET study (Experiment 1: n = 16) demonstrated that acute physical exercise released endogenous DA, and that endogenous DA release was correlated with improvements in RT of the Go/No-Go task. Thereafter, using two electrical muscle stimulation (EMS) studies (Experiments 2 and 3: n = 18 and 22 respectively), we investigated what triggers RT improvement. The EMS studies indicated that EMS with moderate arm cranking improved RT, but RT was not improved following EMS alone or EMS combined with no load arm cranking. The novel mechanistic findings from these experiments are: (1) endogenous DA appears to be an important neuromodulator for RT improvement and (2) RT is only altered when exercise is associated with central signals from higher brain centres. Our findings explain how humans rapidly alter their behaviour using neuromodulatory systems and have significant implications for promotion of cognitive health. KEY POINTS: Acute cardiovascular exercise improves cognitive performance, as evidenced by a reduction in reaction time (RT). However, the mechanistic understanding of how this occurs is elusive and has not been rigorously investigated in humans. Using the neurochemical specificity of [11 C]raclopride positron emission tomography, we demonstrated that acute supine cycling released endogenous dopamine (DA), and that this release was correlated with improved RT. Additional electrical muscle stimulation studies demonstrated that peripherally driven muscle contractions (i.e. exercise) were insufficient to improve RT. The current study suggests that endogenous DA is an important neuromodulator for RT improvement, and that RT is only altered when exercise is associated with central signals from higher brain centres.

Effect of electrical muscle stimulation on cerebrovascular function and cognitive performance.

It is known that electrical muscle stimulation (EMS) can enhance physical function, but its impact on cognition and cerebral hemodynamics is not well understood. Thus, the purpose of this study was to investigate the effects of one EMS session on cerebrovascular function and cognitive performance. The 17 recruited young healthy participants undertook a 25-min session of EMS and a resting control session (Ctrl group) in a random order. Cerebral blood flow velocity (CBFv) in the middle and posterior cerebral arteries (right MCAv and left PCAv, respectively), cerebral oxygenation, cardiac output, and heart rate were measured throughout the sessions, whereas cognitive function was assessed before and after each experimental condition. MCAv, cardiac output, heart rate, and cerebral oxygenation were increased throughout the EMS session, whereas PCAv remained unchanged. In addition, EMS led to improved scores at the Rey auditory verbal learning test-part B and congruent Stroop task versus Ctrl. The present study demonstrates that a single session of EMS may improve cognitive performance and concomitantly increase CBFv and cerebral oxygenation. Therefore, EMS appears to be a valuable surrogate for voluntary exercise and could therefore be advantageously used in populations with severe physical limitations who would not be able to perform physical exercise otherwise.NEW & NOTEWORTHY This study is the first to demonstrate that one session of EMS applied to the quadriceps increases cerebral blood flow velocity and cerebral oxygenation, which are pivotal factors for brain health. Thus, EMS has the potential to be used as an interesting option in rehabilitation to increase cerebral perfusion and defend if not improve cognitive function sustainably for people with severe physical limitations who would not be able to perform physical exercise voluntarily.

Impact of electrical muscle stimulation on serum myostatin level and maintenance of skeletal muscle mass in patients undergoing living-donor liver transplantation: Single-center controlled trial.

AIM: Sarcopenia is reportedly associated with a poor prognosis in patients who undergo living-donor liver transplantation (LDLT), most of whom are not able to tolerate muscle strengthening exercise training. Myostatin is one of the myokines and a negative regulator of skeletal muscle growth. The clinical feasibility of an electrical muscle stimulation (EMS) system, which exercises muscle automatically by direct electrical stimulation, has been reported. In this study, we aimed to determine the effect of perioperative application of SIXPAD, which is a type of EMS system, with reference to the serum myostatin and sarcopenia in LDLT patients. METHOD: Thirty patients scheduled for LDLT were divided into a SIXPAD group (n = 16) and a control group (n = 14). In the SIXPAD group, EMS was applied to the thighs twice daily. The serum myostatin was measured in samples obtained before use of SIXPAD and immediately before LDLT. The psoas muscle index (PMI) at the level of the third lumbar vertebra and the quadriceps muscle area were compared on computed tomography images before use of SIXPAD and 1 month after LDLT. RESULTS: The preoperative serum myostatin was found to be higher in LDLT patients than in healthy volunteers and EMS significantly reduced the serum myostatin. Electrical muscle stimulation prevented a postoperative reduction not only in the area of the quadriceps muscles but also in the PMI despite direct stimulation of the thigh muscles. CONCLUSION: Stimulation of muscles by EMS decreases the serum myostatin and helps to maintain skeletal muscle in patients who have undergone LDLT.

Electrical stimulation of the lower eyelid orbicularis oculi muscle improves periocular dark circles.

BACKGROUND: We developed and tested the safety and efficacy of a cosmetic device to improve dark circles using electrical muscle stimulation of the orbicularis oculi muscle. METHODS: Overall, 18 participants (36 eyes) were studied. The following five items were evaluated before and after the intervention:(1) the Clinical Dark Circle Score using clinical findings and photographs, (2) transcutaneous oxygen partial pressure (TcPO2) on the lower eyelid, (3) thermography, (4) two-dimensional laser blood flowmetry, and (5) spectrophotometry. RESULTS: The mean score at baseline was 2.0 ± 0.90 (mean ± standard deviation), and that at the end of the study was 1.2 ± 1.0 (Wilcoxon signed-rank sum test, p < 0.0001), indicating a significant reduction. The spectrophotometer showed a significant decrease in a* and L* values before and after use (Wilcoxon signed-rank sum test, p < 0.0001). There was also a weak negative correlation between the change in score and the change in blood flow and TcPO2 measured using a laser perfusion device (Spearman's rank correlation coefficient, r = -0.32 and -0.39, respectively). Stratified analysis of the baseline score showed a strong negative correlation between the change in score and the change in spectrophotometric a* in the subjects/group with mild periocular dark circles (Spearman's rank correlation coefficient, r = -0.46). Contrastingly, no correlation was observed for any of the measurements in the subjects/group with severe periocular dark circles. After 1 month, no device-related ophthalmic adverse events were observed in any of the participants. CONCLUSION: Electrical muscle stimulation could improve periocular dark circles, especially in the subjects/group with mild periocular dark circles, and was safe.

Prospective study to assess the efficacy and safety of a noninvasive electro-muscular stimulation for improvement of muscle strength and muscle toning of the extremities.

OBJECTIVE: We sought to evaluate the safety and efficacy of an electrical muscle stimulation (EMS) device in the improvement of muscle strength and toning of the upper extremities. This device, which is FDA-cleared as a two-channel muscle stimulator, provides up to eight electrodes with waveforms inducing muscle stimulation. Although a prior study demonstrated it is safe and effective for use in the abdomen, this system, which has electrodes specifically designed for the extremities, has not previously been evaluated in the upper extremities. METHODS: Forty-five subjects enrolled in the study to assess improvement in arm (i.e., bicep and tricep muscle) strength, and appearance following a protocol of treatments with this bioelectric muscle activation (BMA) device. All subjects received four 30-min EMS treatment sessions in Arm mode-twice weekly for 2 weeks and at least 48 h apart. Follow up visits were also scheduled 30- and 90-days after treatment. Strength was measured with a dynamometer device at baseline, at the final treatment session, and at the posttreatment 30- and 90-day assessment. Subject satisfaction was assessed gauging overall comfort of the treatment and satisfaction including willingness to recommend to others. The changes in strength between initial treatment and final treatment, as well as 30 and 90-day assessment were evaluated. Clinical photography at these visits was also assessed for each patient. Patients were instructed to not modify their normal exercise routine while participating in this study. RESULTS: All 45 subjects completed the treatment protocol. Most patients showed an improvement in muscle strength from the initial to final treatment (i.e., the fourth treatment). Specifically, the maximum bicep strength increased by a mean of 7.5 lbs (22.83%, p = 0.006), while the average increased by a mean of 8.2 lbs (25.76%, p = 0.001) during this period. Similarly, the maximum tricep strength from initial to final treatment increased by a mean of 10.0 lbs (23.16%, p = 0.000), while the average increased by a mean of 9.6 lbs (27.12%, p = 0.000). Thirty days after the last treatment, the maximum bicep strength increased by a mean of 13.3 lbs (34.13%, p = 0.001) while the average increased by a mean of 13.6 lbs (37.05%, p = 0.000) during this period. Similarly, the maximum tricep strength from initial to 30 days postfinal treatment increased by a mean of 10.9 lbs (24.37%, p = 0.000), while the average increased by a mean of 10.5 lbs (29.37%, p = 0.000). Finally, 90 days after the last treatment, the maximum bicep strength increased by a mean of 19.4 lbs (48.4%, p = 0.000), while the average increased by a mean of 17.4 lbs (46.53%, p = 0.000) during this period. Similarly, the maximum tricep strength from initial to 90 days postfinal treatment increased by a mean of 10.8 lbs (27.12%, p = 0.000), while the average increased by a mean of 10.0 lbs (30.94%, p = 0.001). CONCLUSION: This device was well tolerated and resulted in increased strength measurements in the upper extremities, as assessed by a dynamometer, which were sustained at 30 and 90 days.

Cerebral Benefits Induced by Electrical Muscle Stimulation: Evidence from a Human and Rat Study.

Physical exercise (EX) is well established for its positive impact on brain health. However, conventional EX may not be feasible for certain individuals. In this regard, this study explores electromyostimulation (EMS) as a potential alternative for enhancing cognitive function. Conducted on both human participants and rats, the study involved two sessions of EMS applied to the quadriceps with a duration of 30 min at one-week intervals. The human subjects experienced assessments of cognition and mood, while the rats underwent histological and biochemical analyses on the prefrontal cortex, hippocampus, and quadriceps. Our findings indicated that EMS enhanced executive functions and reduced anxiety in humans. In parallel, our results from the animal studies revealed an elevation in brain-derived neurotrophic factor (BDNF), specifically in the hippocampus. Intriguingly, this increase was not associated with heightened neuronal activity or cerebral hemodynamics; instead, our data point towards a humoral interaction from muscle to brain. While no evidence of increased muscle and circulating BDNF or FNDC5/irisin pathways could be found, our data highlight lactate as a bridging signaling molecule of the muscle-brain crosstalk following EMS. In conclusion, our results suggest that EMS could be an effective alternative to conventional EX for enhancing both brain health and cognitive function.

Is it possible to generate an additional pleasant and pain-relieving muscle stimulation when using a low-frequency spinal cord stimulation (SCS) for the treatment of lower back pain? Pilot study: A new technique: "MuscleSCS".

OBJECTIVE: The combined use of spinal cord stimulation (SCS) and muscle stimulation, in the treatment of chronic pain, using the same probe, could improve the clinical results. However, this technique has not been established as yet. It was our hypothesis that it is possible to generate muscle stimulation by using low frequencies with SCS electrodes and use it to additionally treat chronic back pain. METHODS: We generated muscle stimulation in patients with previously implanted SCS electrodes, for the treatment of lower back pain, by using low frequencies (2, 4, 6, and 8 Hz) and different contact combinations of the electrodes. The results were evaluated by using visual inspection (videos), haptic control, surface electromyography (EMG), and sonographic recordings. RESULTS: This pilot study (17 patients, seven females, age 36-87 years, 11 percutaneous paddle leads, and 6 octrodes) was performed at the Neurosurgical Department of the University of Tuebingen. The most preferred frequencies were 6 Hz (45.5% of percutaneous paddle leads) and 8 Hz (50% of octrodes) at contacts 3&4 or 5&6. The preference of frequencies differed significantly among genders (p = 0.023). Simultaneous EMG and ultrasonic recordings demonstrated the generation of muscle potentials and the stimulation of deeper muscle groups. CONCLUSION: In this study, it has been shown that with low-frequency SCS stimulation, pleasant and pain-relieving muscle contractions of the lower and upper back can also be generated. This combined method has been coined by us as "MuscleSCS" technique. Clinical trials are necessary to establish the value of this combined technique and its subtypes.

Skeletal muscle adaptation to indirect electrical stimulation: divergence between microvascular and metabolic adaptations.

NEW FINDINGS: What is the central question of this study? Can we manipulate muscle recruitment to differentially enhance skeletal muscle fatigue resistance? What is the main finding and its importance? Through manipulation of muscle activation patterns, it is possible to promote distinct microvascular growth. Enhancement of fatigue resistance is closely associated with the distribution of the capillaries within the muscle, not necessarily with quantity. Additionally, at the acute stages of remodelling in response to indirect electrical stimulation, the improvement in fatigue resistance appears to be primarily driven by vascular remodelling, with metabolic adaptation of secondary importance. ABSTRACT: Exercise involves a complex interaction of factors influencing muscle performance, where variations in recruitment pattern (e.g., endurance vs. resistance training) may differentially modulate the local tissue environment (i.e., oxygenation, blood flow, fuel utilization). These exercise stimuli are potent drivers of vascular and metabolic change. However, their relative contribution to adaptive remodelling of skeletal muscle and subsequent performance is unclear. Using implantable devices, indirect electrical stimulation (ES) of locomotor muscles of rat at different pacing frequencies (4, 10 and 40 Hz) was used to differentially recruit hindlimb blood flow and modulate fuel utilization. After 7 days, ES promoted significant remodelling of microvascular composition, increasing capillary density in the cortex of the tibialis anterior by 73%, 110% and 55% for the 4 Hz, 10 and 40 Hz groups, respectively. Additionally, there was remodelling of the whole muscle metabolome, including significantly elevated amino acid turnover, with muscle kynurenic acid levels doubled by pacing at 10 Hz (P < 0.05). Interestingly, the fatigue index of skeletal muscle was only significantly elevated in 10 Hz (58% increase) and 40 Hz (73% increase) ES groups, apparently linked to improved capillary distribution. These data demonstrate that manipulation of muscle recruitment pattern may be used to differentially expand the capillary network prior to altering the metabolome, emphasising the importance of local capillary supply in promoting exercise tolerance.

A novel on-demand therapy for lifelong premature ejaculation using a miniature transperineal electrical stimulator-the vPatch: an as-treated analysis.

BACKGROUND: While premature ejaculation (PE) is a common and disturbing sexual dysfunction in men, current available treatment modalities have limited efficacy and low treatment adherence. AIM: To assess the feasibility, safety, and efficacy of the vPatch, a miniaturized on-demand perineal transcutaneous electrical stimulation device for treating PE. METHODS: This prospective bicenter international first-in-human clinical study consisted of 2 arms, was sham controlled, and had a randomized double-blind design. In terms of statistical power calculation, 59 patients aged 21 to 56 years (mean ± SD, 39.8 ± 9.28) with lifelong PE were included. During the initial visit, intravaginal ejaculatory latency time (IELT) was measured over a 2-week run-in period. Eligibility was confirmed in visit 2, based on IELT values, medical and sexual history, and patients' individualized sensory and motor activation thresholds during perineal stimulation with the vPatch. Patients were randomized to the active (vPatch) and sham device groups in a 2:1 ratio, respectively. The vPatch device's safety profile was determined by comparing the incidence of treatment-emergent adverse events. During visit 3, IELTs, Clinical Global Impression of Change scores, and Premature Ejaculation Profile questionnaire outcomes were recorded. Primary end points assessed vPatch device efficacy as mean change in geometric mean IELT; each person was compared with himself, with and without the device, and the sham group was compared with the active group. OUTCOMES: Outcomes included changes in IELT and Premature Ejaculation Profile before and after treatment, last visit Clinical Global Impression of Change scores, and vPatch safety profile. RESULTS: Of 59 patients, 51 completed the study: 34 in the active group and 17 in the sham group. The baseline geometric mean IELT significantly increased from 67 to 123 seconds (P < .01) in the active group, as compared with an insignificant increase from 63 to 81 seconds (P = .17) in the sham group. The increase in mean IELT in the active group was significantly higher than in the sham group (56 vs 18 seconds, P = .01). IELT significantly increased by 3.1 times in the active vs sham group. The mean ratio of fold change (active:sham) was 1.4, significantly different from 1.0 (P = .02). No serious adverse events were reported. CLINICAL IMPLICATIONS: Therapeutic use of the vPatch during coitus may become an on-demand, noninvasive, and drug-free treatment for PE. STRENGTHS AND LIMITATIONS: To our knowledge, this is the first rigorous study investigating whether transcutaneous electrical stimulation during coitus could improve the symptoms of men with lifelong PE. The study is limited by the small number of patients, the exclusion of patients with acquired PE, the short-term follow up, and the use of a device based on a theoretic mechanism of action. CONCLUSION: We demonstrated the possibility to treat lifelong PE by prolonging coitus on demand, using electric stimulation of ejaculation muscles with the vPatch.Clinical trial registration: NCT03942367 (ClinicalTrials.gov).

Physiological adaptations following vigorous exercise and moderate exercise with superimposed electrical stimulation.

INTRODUCTION: Neuromuscular electrical stimulation (NMES) induces involuntary muscle contraction, preferentially promotes anaerobic metabolism, and is applicable for increasing exercise intensity. This study aimed to assess whether superimposing NMES onto moderate-intensity voluntary exercise imitates physiological adaptations that occur in response to vigorous voluntary exercise. METHODS: Eight participants trained with a cycling ergometer at 100% of the ventilatory threshold (VT) (73.3% of peak oxygen consumption) (VOL), and another nine participants trained with the cycling ergometer at 75% of VT (56.2% of peak oxygen consumption) with subtetanic NMES applied to the gluteus and thigh muscles (VOLES), matched to VOL training sessions, for nine weeks. RESULTS: Rating of perceived exertion (RPE) in VOLES (12.00 ± 1.50) was significantly lower than in VOL (14.88 ± 1.81) (p < 0.05) during training sessions. Peak power output during the exercise tolerance test was increased in VOL and VOLES following interventions. Oxygen consumption and heart rate (HR) at VT and blood lactate concentration (BLC) at < VT were decreased from before (PRE) to after (POST) training interventions for both VOL and VOLES. There were no significant differences in absolute changes from PRE to POST for peak power output and oxygen consumption, HR, and BLC at a submaximal intensity between VOL and VOLES. CONCLUSION: Our results suggest that both superimposing subtetanic NMES onto moderate-intensity voluntary exercise and vigorous voluntary intensity exercise induce the improvement in cardiovascular and metabolic systems, but the adaptation of former method is provided without perceived strenuous exertion.

Electrical muscle stimulation in young adults: effect of muscle volume on brain-derived neurotrophic factor levels.

PURPOSE: Electrical muscle stimulation (EMS) is known to be effective at stimulating brain-derived neurotrophic factor (BDNF) levels, but the relationship between the volume of muscle stimulated and BDNF levels is not clear. The purpose of this study was to quantify BDNF as a function of muscle volume stimulated in young adults. METHODS: Twelve young adults (male, n = 9, age = 27.3 ± 5.5 years) were enrolled in this study. Participants completed three testing conditions in randomized order: 23 min of maximum tolerated bilateral stimulation of (1) the quadriceps muscle or (2) the musculature of the entire lower limbs and (3) control testing and retesting after 23 min without an intervention. Blood samples were collected before, immediately after, 20 min after, and 40 min after the intervention when EMS was applied to the thighs or the entire lower limb conditions. Serum obtained from blood collection was used for BDNF analysis. RESULTS: The delta value of BDNF for the test and retest in the control condition was - 42.1 ± 73.8 pg/mL, and there was no significant difference between the test and retest BDNF. Compared to stimulation of the quadriceps muscle, stimulation of the entire lower limbs produced significantly higher BDNF at 20 min post-treatment than those at pre-treatment or 40 min post-treatment, and BDNF was also significantly higher immediately post-treatment than those at pre-treatment. Only stimulation of the quadriceps muscle did not induce a significant change between pre- and post-treatment. CONCLUSION: Our findings suggest that the volume of muscle stimulation is important for increased BDNF.

Evaluation of Electric Muscle Stimulation Method for Haptic Augmented Reality.

Currently, visual Augmented Reality (AR) technology is widespread among the public. Similarly, haptic AR technology is also widely practiced in the academic field. However, conventional haptic AR devices are not suitable for interacting with real objects. These devices are often held by the users, and they contact the real object via the devices. Thus, they prevent direct contact between the user and real objects. To solve this problem, we proposed employing Electrical Muscle Stimulation (EMS) technology. EMS technology does not interfere with the interaction between the user and the real object, and the user can wear the device. First, we examined proper stimulus waveforms for EMS, in addition to pulse waveforms. At the same time, we examined the appropriate frequency and pulse width. The waveforms that we used this time were a sawtooth wave, a reverse sawtooth wave, and a sine wave. Second, to clarify the characteristic of the force presented by the EMS, we measured the relationship between the input voltage and the force presented and obtained the point of subjective equality using the constant method. Subsequently, we presented the bump sensation using EMS to the participants and verified its effectiveness by comparing it with the existing methods.

Effects of Functional Electrical Stimulation on Gait Characteristics in Healthy Individuals: A Systematic Review.

BACKGROUND: This systematic review aimed to provide a comprehensive overview of the effects of functional electrical stimulation (FES) on gait characteristics in healthy individuals. METHODS: Six electronic databases (PubMed, Embase, Epistemonikos, PEDro, COCHRANE Library, and Scopus) were searched for studies evaluating the effects of FES on spatiotemporal, kinematic, and kinetic gait parameters in healthy individuals. Two examiners evaluated the eligibility and quality of the included studies using the PEDro scale. RESULTS: A total of 15 studies met the inclusion criteria. The findings from the literature reveal that FES can be used to modify lower-limb joint kinematics, i.e., to increase or reduce the range of motion of the hip, knee, and ankle joints. In addition, FES can be used to alter kinetics parameters, including ground reaction forces, center of pressure trajectory, or knee joint reaction force. As a consequence of these kinetics and kinematics changes, FES can lead to changes in spatiotemporal gait parameters, such as gait speed, step cadence, and stance duration. CONCLUSIONS: The findings of this review improve our understanding of the effects of FES on gait biomechanics in healthy individuals and highlight the potential of this technology as a training or assistive solution for improving gait performance in this population.

Correction effects of peroneus longus contraction on hallux valgus radiographic parameters.

BACKGROUND: Hypermobility of the first tarsometatarsal joint plays an important role in hallux valgus pathogenesis. The peroneus longus is recognized as a dynamic stabilizer of the first tarsometatarsal joint. However, the association between the peroneus longus function and the hallux valgus deformity remains unknown. This study aimed to determine the effect of peroneus longus contraction induced by electrical muscle stimulation on the correction of hallux valgus radiographic parameters in patients with hallux valgus. METHODS: Thirty-five patients with hallux valgus (47 feet; 2 men, 33 women; mean age 64.9 years) were included. Non-weight-bearing dorsoplantar radiographs of the foot were obtained with and without electrical muscle stimulation of the peroneus longus. Radiographic parameters of hallux valgus deformities, including the hallux valgus angle, intermetatarsal angle, first metatarsal protrusion distance, and distance between the first and second metatarsal bases, were measured and compared between the two conditions. RESULTS: All hallux valgus radiographic parameters were significantly improved by contraction of the peroneus longus. The median hallux valgus angle decreased by 13.2°. Fewer changes in the hallux valgus angle were identified in patients with severe deformity and geriatric patients. CONCLUSIONS: Although the peroneus longus muscle has received little attention in the management of hallux valgus, our findings suggest that it has the potential to be a novel conservative approach for treating mild-to-moderate hallux valgus.

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

OBJECTIVES: This 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 METHODS: We 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. RESULTS: This 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. CONCLUSIONS: Active 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.

New setup for multi-parametric MRI in young and old rat gastrocnemius at 4.7 and 7 T during muscle stimulation.

T1 and T2 relaxation times combined with 31 P spectroscopy have been proven efficient for muscular disease characterization as well as for pre- and post-muscle stimulation measurements. Even though 31 P spectroscopy can already be performed during muscle exercise, no method for T1 and T2 measurement enables this possibility. In this project, a complete setup and protocol for multi-parametrical MRI of the rat gastrocnemius before, during and after muscle stimulation at 4.7 and 7 T is presented. The setup is fully MRI compatible and is composed of a cradle, an electro-stimulator and an electronic card in order to synchronize MRI sequences with muscle stimulation. A 2D triggered radial-encoded Look-Locker sequence was developed, and enabled T1 measurements in less than 2 min on stimulated muscle. Also, a multi-slice multi-echo sequence was adapted and synchronized for T2 measurements as well as 31 P spectroscopy acquisitions in less than 4 min in both cases on stimulated muscle. Methods were validated on young rats using different stimulation paradigms. Then they were applied on older rats to compare quantification results, using the different stimulation paradigms, and allowed observation of metabolic changes related to aging with good reproducibility. The robustness of the whole setup shows wide application opportunities.

Effects of three neuromuscular electrical stimulation methods on muscle force production and neuromuscular fatigue.

This study compared the acute responses of three neuromuscular electrical stimulation (NMES) methods on muscle torque-time integral (TTI) and neuromuscular fatigue. Narrow-pulse (0.2 ms; NP), wide-pulse (1 ms; WP), and tendon vibration superimposed onto wide-pulse (WP + VIB)-NMES conditions were applied to sixteen healthy individuals (n = 16) in three separate sessions in a randomized order. Stimulation intensity was set to elicit 20% of maximal voluntary contraction (MVC); the stimulus pattern comprised four sets of 20 repetitions (5 s On and 5 s Off) with a one-minute inter-set interval. TTI was measured for each NMES condition and MVC, voluntary activation (VA), peak twitch torque (Peaktwitch ), and peak soleus (EMGSOL ), medial (EMGMG ), and lateral gastrocnemius (EMGLG ) electromyography were measured before and immediately after each NMES condition. TTI was higher during WP + VIB (19.63 ± 6.34 MVC.s, mean difference = 3.66, p < 0.001, Cohen's d = 0.501) than during WP (15.97 ± 4.79 MVC.s) condition. TTI was higher during WP + VIB (mean difference = 3.79, p < 0.001, Cohen's d = 0.626) than during NP (15.84 ± 3.73 MVC.s) condition. MVC and Peaktwitch forces decreased (p ≤ 0.001) immediately after all conditions. No changes were observed for VA (p = 0.365). EMGSOL amplitude reduced (p = 0.040) only after NP, yet EMGLG and EMGMG amplitudes decreased immediately after all conditions (p = 0.003 and p = 0.013, respectively). WP + VIB produced a higher TTI than WP and NP-NMES, with similar amounts of neuromuscular fatigue across protocols. All NMES protocols induced similar amounts of peripheral fatigue and reduced EMG amplitudes.

Combination of monopolar 2 MHz radiofrequency and electrical multidirectional stimulation for reducing abdominal circumference and enhancing the muscle definition in subjects with overweight range body mass index.

BACKGROUND: The popularity of noninvasive body contouring procedures has been steadily increasing in recent years, however, studies evaluating its effectiveness in individuals with overweight range body mass index (BMI) are limited. OBJECTIVE: To evaluate the efficacy and safety of combined 2 MHz radiofrequency (RF) and electrical multidirectional stimulation (EMDS) for the improvement of the abdominal contour in subjects with overweight range BMI. METHODS: Twelve participants with overweight range BMI (23.6-24.9 kg/m2 ) underwent a single RF treatment, followed by a series of six EMDS treatments. Follow-up assessments (abdominal circumference [AC] and skinfold thickness measurements) were scheduled 1, 2, and 3 months after the final session. RESULTS: At 1 month after the final treatment, a 3.1% (2.6 ± 0.47 cm, mean ± SD) significant reduction in mean AC was observed (p ˂ 0.001) and a maximal skinfold thickness reduction of 14% (4.6 ± 1.1 mm) was also noted (p = 0.032). Transient dysesthesia lasting 2-3 hours after EMDS treatment was the most common adverse effect reported by 5 of 12 subjects (41.7%), with no other serious side effects. CONCLUSIONS: Combined RF and EMDS treatments are safe and effective, yielding significant reductions in both AC and skinfold thickness in patients with overweight range BMI, causing only minimal and transient adverse effects.

Knee extensor force production and discomfort during neuromuscular electrical stimulation of quadriceps with and without gluteal muscle co-stimulation.

PURPOSE: To investigate whether Neuromuscular Electrical Stimulation (NMES) simultaneously applied on the quadriceps (Q) and gluteal (G) muscles, as compared to single Q-stimulation alters the knee extensor force production and discomfort. METHODS: A total of 11 healthy participants (6 females), with normal weight and age between 19 and 54 years were included. The unilateral, isometric maximal voluntary contraction (MVC) was assessed for each participant in an isokinetic dynamometer (Biodex, system 3). NMES was, in a randomized order, applied only on the Q-muscle and on the Q- and G-muscles (QG) simultaneously. NMES-intensity was increased stepwise until the maximal tolerable level was reached regarding discomfort, graded according to the visual analogue scale (VAS). VAS and the % of MVC produced by NMES, were registered for each level, expressed as median (inter-quartile range). RESULTS: The maximum tolerated NMES-intensity applied on Q compared to QG resulted in equally high discomfort, 8.0 (6.0-9.0) vs 8.0 (6.3-9.0), and in equivalent knee extensor force production, 36.7 (29.9-47.5) and 36.2 (28.9-49.3), respectively, in % of MVC. At 20% of MVC, NMES applied on Q compared to QG resulted in equal acceptable discomfort, 3.0 (2.0-4.5) vs 3.0 (3-5.5), and comparable intensity levels, 41.5 (38.0-45.8) vs 43.5 (37.0-48.8), respectively. CONCLUSIONS: Simultaneous QG-NMES, as compared to single Q-NMES, does not seem to affect the knee extensor force production or discomfort. Q-NMES, without voluntary muscle contraction, can with an acceptable level of discomfort result in at least 20% of MVC.

Constant Load Pedaling Exercise Combined with Electrical Muscle Stimulation Leads to an Early Increase in Sweat Lactate Levels.

A novel exercise modality combined with electrical muscle stimulation (EMS) has been reported to increase cardiovascular and metabolic responses, such as blood lactate concentration. We aimed to examine the effect of constant load pedaling exercise, combined with EMS, by non-invasively and continuously measuring sweat lactate levels. A total of 22 healthy young men (20.7 ± 0.8 years) performed a constant load pedaling exercise for 20 min at 125% of the pre-measured ventilatory work threshold with (EMS condition) and without (control condition) EMS stimulation. Blood lactate concentration was measured by blood samples obtained from the earlobe every minute. Sweat lactate was monitored in real time using a sensor placed on the forearm. The sweat lactate threshold (sLT) was defined as the point of increase in sweat lactate. sLT occurred significantly earlier in the EMS condition than in the control condition. In the single regression analysis, the difference in sLT between the two conditions, as the independent variable, was a significant predictor of the difference in blood lactate concentrations at the end of the exercise (p < 0.05, r = −0.52). Sweat lactate measurement may be a noninvasive and simple alternative to blood lactate measurement to determine the effectiveness of exercise combined with EMS.