Search Results (94)

Transcutaneous spinal cord stimulation (tSCS) is a promising neuromodulation approach for motor recovery after spinal cord injury (SCI), yet clinical programming remains largely dependent on subjective parameter selection. This study evaluated high-density surface EMG (HD-sEMG)–derived spatial and temporal features as objective biomarkers for tSCS optimization in three adults with chronic cervical SCI. A 64-channel electrode array recorded stimulation-evoked responses across five cervical stimulation levels, four pulse widths, and graded amplitudes. Features describing activation magnitude, spatial distribution, cluster morphology, and temporal dynamics were extracted from epoch-based activation maps. Of the three enrolled participants, two demonstrated measurable stimulation-evoked responses and contributed to the paired-pulse analyses, whereas pulse-width analyses were limited to a single responsive muscle (left flexor carpi) in one participant. Paired-pulse analysis identified root mean square (RMS) as the most discriminative feature, revealing nonlinear, muscle- and level-specific dose–response relationships in which maximal suppression often occurred at intermediate rather than maximal amplitudes. Increasing pulse width expanded the spatial extent of recruitment (active area: p = 0.006; convex hull area: p = 0.004) without altering response timing. Polarity reversal analysis demonstrated stable innervation zone localization across stimulation levels and amplitudes. These findings establish a spatially resolved HD-sEMG framework that may support individualized tSCS parameter selection in SCI. Full article

Background/Objectives: Pediatric spinal cord injury (SCI) is a rare yet highly disabling condition associated with substantial functional and psychosocial impairments. Although robot-assisted gait training (RAGT) and transcutaneous spinal cord stimulation (tSCS) have independently demonstrated promising results, evidence regarding their combined use in pediatric SCI is limited. This study aimed primarily to assess the feasibility and safety of combining RAGT with tSCS in children with incomplete SCI, and secondarily to explore its effects on clinical outcomes. Methods: A case series study was conducted that included three pediatric participants (<18 years) with chronic incomplete SCI (AIS C–D). Participants completed five consecutive sessions of RAGT using a Lokomat device combined with tSCS applied at the lumbosacral level. Each session consisted of 30 min of gait training, including 20 min of concurrent electrical stimulation. Safety was assessed through adverse-event monitoring and pain evaluation. Clinical outcomes included gait speed (10MWT), trunk control (SATCo), lower-limb strength (LEMS), and spasticity (MAS). Results: Session adherence reached 100%. Skin erythema was the most frequently reported adverse event and showed a clear association with tSCS. All participants demonstrated improvements in gait speed, with two exceeding the minimal clinically important difference. Secondary results showed similar outcomes for spasticity, strength, and trunk control, with no clinically meaningful changes in any case. Conclusions: The combined application of RAGT and tSCS appears to be a feasible and safe intervention for children with incomplete SCI. Preliminary findings suggest potential benefits in gait speed, thereby supporting the need for further investigation with larger samples and controlled study designs. Full article

Spinal cord injury (SCI) is frequently accompanied by abnormal muscle tone and spasticity, which impair voluntary motor control, mobility, and quality of life. Although classically defined as velocity-dependent hyperreflexia, tone abnormalities after SCI encompass a broader spectrum, including sustained muscle activation, co-contraction, clonus, and non–velocity-dependent resistance to movement. These manifestations arise from distributed changes across spinal and supraspinal motor systems. At the segmental level, SCI induces maladaptive plasticity involving motoneurons, interneurons, sensory afferents, and muscle, including dysregulated persistent inward currents, altered inhibitory neurotransmission, afferent hyperexcitability, synaptic reorganization, and structural muscle remodeling. In parallel, supraspinal adaptations—including cortical motor map reorganization, reduced intracortical inhibition, corticospinal–reticulospinal imbalance, loss of monoaminergic modulation, and altered brainstem and cerebellar regulation—further amplify spinal circuit gain and impair inhibitory control of tone. Current pharmacologic treatments largely suppress symptoms without addressing these underlying circuit changes, while invasive neuromodulatory strategies are limited by surgical risk or state-dependent effects. This review synthesizes emerging insights into the multilevel mechanisms regulating abnormal tone after SCI and examines neuromodulatory approaches targeting spinal and supraspinal networks. Particular attention is given to transcutaneous spinal cord stimulation (TcSCS), a non-invasive method capable of modulating segmental reflex circuits and descending control pathways. Advances in transcriptomic and epigenetic profiling may further enable mechanism-based therapies and biomarker-guided strategies for treating spasticity. Full article

Background: Transcutaneous spinal cord stimulation (tSCS) is a promising approach to enhance functional recovery after spinal cord injury (SCI). However, evidence on repeated sessions and their effects on gait and lower-limb strength remains limited. This study evaluated the effects of multisegmental tSCS on walking ability, muscle strength, and functional independence in individuals with SCI. Methods: In this randomized controlled trial with a partial crossover design, twelve individuals received tSCS combined with gait rehabilitation, while ten underwent gait rehabilitation alone, for three weeks. Four participants crossed over to the tSCS group after a minimum one-week washout period following the control intervention. We assessed the American Spinal Injury Association Impairment Scale (AIS), Total Motor Score (TMS), Lower Extremity Motor Score (LEMS), Walking Index for Spinal Cord Injury II (WISCI-II), 10- and 6-Meter Walking Tests (10MWT, 6meterWT), Timed Up and Go (TUG) test, maximal voluntary contraction (MVC) of the quadriceps (QM) and tibialis anterior (TA), and the Spinal Cord Independence Measure (SCIM-III); tSCS was applied at three spinal segments during gait rehabilitation over 15 sessions. Results: tSCS significantly improved MVC in both muscles, as well as SCIM-III and TUG, and these improvements were maintained at follow-up, with no significant adverse events reported. Other clinical assessments also showed significant improvement in both groups. Conclusions: tSCS was well tolerated and conferred additional benefits in lower-limb muscle strength, walking ability (as assessed by TUG), and functional independence, supporting its potential as a valuable adjunct to rehabilitation. Full article

Introduction: Multiple Sclerosis (MS) is frequently associated with a range of neurological, cognitive and psychological issues, presenting significant challenges to patients’ Quality of Life (QoL). Among non-invasive neuromodulation techniques, transcutaneous spinal Direct Current Stimulation (tsDCS) is emerging as a potential approach for symptom management in neurological conditions. However, the effects of tsDCS on MS remain poorly explored. Thus, this preliminary study aimed to evaluate the effects of tsDCS on MS symptomatology, focusing on cognitive and psychological variables. Methods: Six patients with MS were recruited for a randomized, sham-controlled, double-blind crossover study, and received anodal tsDCS or sham stimulation in two separate sessions at least one month apart. Assessment outcomes included cognitive and attentional-executive functions, depressive symptoms, and several QoL components. The tests were administered at baseline (T0), immediately after treatment (T1), one week (T2) and one month (T3) post-treatment. Results: Although protocol-by-time interactions did not reach statistical significance across all measures, protocol-independent improvements over time were observed in various QoL subscales, including Physical Functioning, Role Limitations due to Physical Health, Vitality, Health Distress, and Overall QoL. Conclusions: Our findings indicate that tsDCS is a feasible and well-tolerated intervention in patients with MS, with possible implications for QoL. Given the small sample size and the exploratory nature of this study, further research is needed to clarify whether tsDCS may represent a potentially beneficial non-invasive neuromodulation approach for improving well-being in patients with MS across both physical and mental dimensions. Full article

Background/Objectives: Vagus nerve stimulation (VNS) has evolved from a laboratory experiment to a standard of care in several neurological disorders like epilepsy, depression and stroke rehabilitation at present. Methods: We reviewed the published literature relevant to its origins in animal models leading to various clinical applications. Results: Bailey and Bremer published their observations following VNS in animals while further studies established its utility in some forms of epilepsy. Subsequent observations in epilepsy patients treated with VNS revealed the unequivocal improvement in psychological and behavioral disorders. Consequently, VNS received approval for its application in resistant depression disorders. Multiple studies revealed changes due to neuronal plasticity following VNS that could result in the significant clinical recovery of motor function in chronic ischemic stroke patients. Chronic incomplete cervical spinal cord injury, head injury and peripheral nerve injury deficits are also being studied for recovery patterns. Transcutaneous approaches and closed-loop stimulation are showing encouraging results that may facilitate the extension of the application of neuromodulation using VNS. Conclusions: For the recovery of motor function following paralysis in stroke patients or cervical spinal cord injuries, the timing of the stimulation after physical activity during rehabilitation has been identified as a key factor. In addition to the timing of the stimulation, the titration of the parameters is also being studied to obtain optimized recovery in cases of motor, sensory, or sphincter deficits. Full article

Pupillometry can be used as a method for monitoring pain. There are experimental conditions under which standard pupillometry equipment cannot be used. Studying the effects of different pulse forms used for transcutaneous spinal cord stimulation (tSCS) is one such task. The aim was to create a system for recording pupil diameter based on a web camera because it can be synchronised with external equipment, which allows the diameter to be recorded simultaneously with other physiological signals. A markerless system for recording and analysing pupil diameter using deep neural networks was developed based on a commercially available web camera. The accuracy of this system was compared with the accuracy of measurements using manual analysis with ImageJ (version 1.54g). For validation, the system was tested in a study of the dependence of tolerance to tSCS on the shape of stimulating pulses, which involved volunteers (n = 12). The results of the developed pupillometry were compared with the pain rating scale traditionally used in such studies. The developed system is accurate in determining the pupil diameter, comparable to human accuracy. The pupillometry results reproduced those obtained using a subjective pain scale. This method was found to be a reliable method for recording nociceptive pupillary responses in electrophysiology. Full article

Background: Central cord syndrome (CCS) is the most common incomplete spinal cord injury, producing more severe motor deficits in the upper than lower extremities and impairing sensory and autonomic function. Although transcutaneous spinal cord stimulation (tSCS) has shown benefits in motor and sensory recovery after spinal cord injury, studies have not explicitly documented whether CCS subjects were included. The aim of this study was to assess the effects of tSCS over 12 weeks on motor and sensory outcomes in a subject with CCS. Methods: A 20-year-old male with a C7 injury was evaluated at baseline and after 12 weeks with the American Spinal Cord Injury Impairment scale, Modified Ashworth Scale, Penn and Spasm Frequency Scale, 3-Meter Walk Test and 6-Minute Walk Test, 9-Hole Peg Test, Box and Block Test, hand dynamometry, and lower-limb EMG. tSCS was applied between T9 and L1 at 30 Hz. Results: At 12 weeks, upper-limb motor and sensory scores improved, while spasm frequency and hand spasticity were reduced. Manual dexterity improved bilaterally in the 9-Hole Peg and Box and Block Tests, with a 2 kg gain in right-hand grip strength. In the 6-Minute Walk Test, the distance covered increased from 224.4 m to 295.2 m, and a 1.36 s reduction in 3-Meter walking time was achieved. Conclusions: tSCS improved motor and sensory function and reduced spasticity and spasms. These findings suggest that tSCS may serve as an effective complementary intervention for motor and sensory rehabilitation in individuals with mild cervical injuries, including CCS. Full article

(1) Background: We developed a novel technology that regulates human locomotion using transcutaneous electrical spinal cord stimulation to activate spinal locomotor networks and posterior root stimulation to activate leg flexor and extensor motor pools during swing and stance phases, respectively. This technology effectively restores walking in post-stroke individuals while forward propulsion in the stance phase and foot dorsiflexion in the swing phase are insufficient. In this study the effectiveness of regulating the stance and swing phases while healthy volunteers walked on a treadmill with transcutaneous electrical stimulation of the posterior roots, leg muscles, and their combined effects has been examined. (2) Methods: We analyzed the kinematic characteristics of stepping movements in healthy participants with spinal stimulation of the posterior roots and flexor/extensor leg muscles. (3) Results: Our findings clearly show that posterior root stimulation at T12 combined with tibialis anterior muscle stimulation during the swing phase effectively regulates foot dorsiflexion, whereas posterior root stimulation at L2 combined with hamstrings and medial gastrocnemius stimulation during the stance phase effectively regulates forward propulsion. (4) Conclusions: Combined stimulation in the stance and swing phases within the same gait cycle resulted in the most coordinated stepping, and effective control of forward propulsion and foot dorsiflexion. Full article

Cervical spinal cord injury causes severe functional impairment with limited spontaneous recovery, and while spinal cord stimulation has emerged as a promising neuromodulatory strategy, evidence for cervical applications remains fragmented. To address this gap, we conducted a systematic review synthesizing preclinical and clinical evidence on cervical spinal cord stimulation for functional rehabilitation following spinal cord injury. The review was registered on PROSPERO (CRD420251088804) and conducted in accordance with PRISMA guidelines, with PubMed, Embase, IEEE Xplore, and Web of Science searched from inception to July 2025 for animal and human studies of cervical spinal cord stimulation, including epidural, intraspinal, and transcutaneous approaches, reporting functional neurological outcomes. Risk of bias was assessed using the Cochrane RoB 2 and ROBINS-I tools, and due to substantial heterogeneity, results were synthesized narratively. Thirty-one studies comprising 119 animals and 156 human participants, met inclusion criteria. Across studies, outcome measures such as GRASSP, ISNCSCI, and dynamometry consistently demonstrated improvements in hand strength, dexterity, and voluntary motor activation. Several studies also reported gains in sensory and autonomic function, whereas respiratory outcomes were infrequently assessed. Adjunctive interventions, including cortical stimulation, brain–computer interface priming, and task-specific training frequently augmented recovery. Adverse events were generally mild, although overall risk of bias was predominantly serious. Overall, cervical spinal cord stimulation demonstrates preliminary assistive and therapeutic effects on motor recovery, with additional sensory, autonomic, and potential respiratory benefits. Full article

Background/Objectives: Migraine is a complex neurological headache disorder, and transcutaneous auricular vagus nerve stimulation (taVNS) can effectively relieve headache symptoms, but its mechanism of effect is still unclear. This study aimed to explore the regulatory effects of taVNS on the locus coeruleus (LC) and the norepinephrine (NE) system in migraine mice. Methods: C57/BL6 mice were randomly assigned to four experimental groups: the control group, model group, taVNS group, and sham taVNS group. A migraine model was established by administration of nitroglycerin. Headache behaviors were assessed using the orofacial stimulation test (OST) and the mouse grimace scale (MGS). Immunofluorescence staining was conducted to evaluate the expression of NE neurons in the LC, while Western blotting was used to determine the expression levels of α-2A adrenergic receptors in the spinal trigeminal nucleus caudalis (Sp5C). Additionally, fiber-optic recording was employed to monitor the real-time dynamics of NE release in Sp5C. Results: After taVNS intervention, the drinking time of OST in the model mice was significantly prolonged(p < 0.05), and facial expression scores were reduced (p < 0.05). TaVNS increased the number of NE neurons in the LC (p < 0.05), promoted the release of NE in Sp5C (p < 0.05), and upregulated the expression of α-2A adrenergic receptors in Sp5C (p < 0.05). Conclusions: The analgesic effects of taVNS are related to the activation of the LC-NE system and the inhibition of the decrease in Sp5C in migraine mice. Full article

Background/Objectives: Transcutaneous spinal stimulation (TSS) is a noninvasive stimulation approach for spasticity reduction in people with spinal cord injury (SCI). We enrolled 17 individuals with SCI who experience lower extremity hyperreflexia for this randomized crossover study to compare single-session effects of 3 TSS conditions: single-site continuous (SS-CONT), single-site burst (SS-BURST), and dual-site continuous (DS-CONT). Methods: Each TSS condition was delivered for 30 min with participants in supine via a cathode over the thoracic spine (T11–T12) and an anode over the abdomen. A second cathode was placed over the lumbar spine (L1/2 or L2/3) for DS-CONT. SS-CONT and DS-CONT stimulation was delivered as continuous 50 Hz stimulation with a 1 ms pulse width. SS-BURST stimulation was delivered as 4 bursts/second of 50 Hz stimulation with a 1 ms pulse width. Pendulum test first swing excursion (FSE) and ankle clonus drop test first drop excursion (FDE) were measured at baseline and immediately post-intervention to assess quadriceps and soleus spasticity, respectively. FSE and FDE of the first trial (FSE_T1 and FDE_T1) and the average of 3 trials (FSE_avg and FDE_avg) were included in analyses. Subgroup analyses were performed based on baseline level of spasticity (high vs. low). Results: Between-condition analyses showed no significant differences; however, SS-CONT (FSE_T1 d = 0.30, FSE_avg d = 0.27) and DS-CONT (FSE_T1 d = 0.33, FSE_avg d = 0.12) stimulation demonstrated the largest effect sizes for FSE measures, and SS-CONT (FDE_T1 d = 0.32, FDE_avg d = 0.31) stimulation demonstrated the largest effect size for FDE measures. Significant fair correlations between baseline FSE measures and change in FSE were identified when all conditions were combined. A significant fair correlation between baseline FDE_T1 and change in FDE_T1 was identified when data were collapsed across conditions. In subgroup analyses, only participants with high baseline quadriceps spasticity showed a significant decrease in quadriceps spasticity with DS-CONT (∆FSE_T1 = 14.8 ± 13.0°), SS-BURST (∆FSE_T1 = 4.1 ± 4.5°), and with all conditions combined (∆FSE_T1 = 11.3 ± 16.5°, ∆FSE_avg = 7.2 ± 13.1°). For participants with low baseline soleus spasticity, DS-CONT stimulation significantly increased soleus spasticity (∆FDE_T1 = −12.2 ± 9.3°, ∆FDE_avg = −8.5 ± 8.4°). Conclusions: When data were collapsed across conditions, TSS did not result in a significant reduction in quadriceps or soleus spasticity. Continuous stimulation at both single- and dual-sites was associated with the largest effect on quadriceps spasticity when all participants were combined. Lastly, TSS reduced spasticity in a severity-dependent manner. Full article

Objectives: This review seeks to evaluate the effectiveness of electrical stimulation (ES) in improving upper limb function in children and young people (CYP) with hemiplegic cerebral palsy (HCP). Methods: A systematic literature search from inception until May 2025 was conducted. Various study designs comparing the effect of different ES techniques such as functional electrical stimulation (FES), transcutaneous electrical nerve stimulation (TENS), neuromuscular electrical stimulation (NMES), transcutaneous spinal cord stimulation (TSCS), and transcranial direct current stimulation (tDCS) on upper limb function in CYP with HCP were included. Results: Eighteen studies were selected for review and quality assessment, comprising twelve randomised controlled trials (RCTs) and six non-RCTs. FES was shown to improve upper limb function, though more rigorous and controlled research is needed. Both TENS and NMES demonstrate potential to improve upper limb function, particularly when combined with other interventions. The analysis suggests that variability in reporting tDCS outcomes hinders assessment of its potential benefits for improving upper limb function. Conclusions: Current research suggests ES may support upper limb rehabilitation in CYP with HCP, though the overall evidence remains limited. Most studies are small, underpowered, and lack long-term follow-up, limiting confident conclusions. ES should therefore be applied cautiously and only as part of a comprehensive rehabilitation plan. Full article

Background/Objectives: Cardiovascular (CV) dysfunction and, specifically, orthostatic hypotension, may significantly impact the quality of life of individuals with spinal cord injuries (SCIs) at T6 or above. While spinal cord transcutaneous stimulation (scTS) has shown immediate effects on blood pressure regulation, its long-term effects remain largely unexplored. Methods: This case study examines the sustained effects of scTS on blood pressure regulation and orthostatic tolerance in a 33-year-old female with cervical (C4) complete SCI sustained two years earlier. This individual underwent an initial baseline tilt test without stimulation, completed six 30 min scTS-CV sessions (cardiovascular-focused stimulation) over two weeks as the “training” phase, and then had repeated tilt tests without stimulation posttraining. Results: Following training, the participant demonstrated an improvement in orthostatic tolerance, maintaining a 70° tilt for 30 min, compared to only 3 min at baseline, in a tilt test (without stimulation) conducted one day posttraining. Self-reported reduction in orthostatic burden and decreased midodrine dependence were also observed for several weeks, with improvements diminishing by 6 weeks posttraining. Conclusions: These observations suggest that brief, repeated scTS-CV sessions may lead to sustained improvements in orthostatic tolerance beyond the immediate period of stimulation. Although the duration of these effects has yet to be established, this approach could offer a non-invasive alternative for managing CV dysfunction in SCIs. Full article

Background/Objectives: Respiratory impairment is the leading cause of morbidity and mortality in participants with spinal cord injury (SCI). Cervical SCI (cSCI) severely compromises respiratory function due to paralysis and weakness of the respiratory muscles. Recent evidence suggests that transcutaneous electrical spinal cord stimulation (tSCS) may enhance motor strength and promote functional recovery. Therefore, cervical tSCS, applied at cervical segments, holds potential as a therapeutic strategy to improve respiratory function in participants with cervical SCI. Methods: This randomized controlled trial with a partial crossover design included participants with both complete and incomplete cSCI. Neurological assessments were used, as well as tests to evaluate pulmonary function maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), and spirometric measurements. These assessments were conducted at baseline and after the last session. The experimental group received tSCS at the C3–C4 and C6–C7 cervical spinal levels, delivered at a frequency of 30 Hz during occupational therapy. The control group underwent identical occupational therapy sessions without stimulation. Each session lasted 30 min and was conducted over eight days. Results: Fifteen participants with cSCI received tSCS, while 11 cSCI participants were included in the control group. Seven participants took part in both groups. Only the tSCS group showed significant improvements in MIP, MEP, and forced vital capacity (p < 0.05), while no significant changes were observed in the control group. Conclusions: tSCS applied at the cervical segments can promote respiratory function following cervical SCI. This approach may support neuroplasticity and help reduce long-term respiratory complications in participants with cervical SCI. However, to confirm these effects, long-term stimulation protocols and follow-up studies in larger SCI populations are required. Full article