Feasibility of complex exercise therapy with Standing Ovation and peripheral neuromodulation for gait rehabilitation after incomplete spinal cord injury-a case report.

BACKGROUND: Spinal cord injuries (SCIs) are a global concern, annually affecting hundreds of thousands of individuals. Among these cases, incomplete SCIs, allowing some muscle activity below the injury, pose unique challenges. This case study focuses on a 55-year-old male with a moderate incomplete SCI (AIS-D). CASE PRESENTATION: After initial treatments and pharmaceutical antispastic therapy, a novel intervention was introduced featuring the Standing Ovation gait exercise system (Standing Ovation GmbH, Hallwang, Austria). This individually tailored system, equipped with a rail system and seat-lifting unit, provided a secure environment for balance training. Over 14 training sessions spanning from October 13, 2021, to March 23, 2022, improvements in functional walking were observed. DISCUSSION AND CONCLUSION: Locomotor improvement in SCI rehabilitation is important; the potential of task-specific gait exercises with the Standing Ovation system in incomplete spinal cord injury seems to be a promising approach. Although promising, these findings call for further systematic studies with larger patient cohorts to strengthen their reliability. Ongoing research endeavors are essential to fully understand the benefits and limitations of this intervention in spinal cord injury rehabilitation.

Neurophysiology of epidurally evoked spinal cord reflexes in clinically motor-complete posttraumatic spinal cord injury.

Increased use of epidural Spinal Cord Stimulation (eSCS) for the rehabilitation of spinal cord injury (SCI) has highlighted the need for a greater understanding of the properties of reflex circuits in the isolated spinal cord, particularly in response to repetitive stimulation. Here, we investigate the frequency-dependence of modulation of short- and long-latency EMG responses of lower limb muscles in patients with SCI at rest. Single stimuli could evoke short-latency responses as well as long-latency (likely polysynaptic) responses. The short-latency component was enhanced at low frequencies and declined at higher rates. In all muscles, the effects of eSCS were more complex if polysynaptic activity was elicited, making the motor output become an active process expressed either as suppression, tonic or rhythmical activity. The polysynaptic activity threshold is not constant and might vary with different stimulation frequencies, which speaks for its temporal dependency. Polysynaptic components can be observed as direct responses, neuromodulation of monosynaptic responses or driving the muscle activity by themselves, depending on the frequency level. We suggest that the presence of polysynaptic activity could be a potential predictor for appropriate stimulation conditions. This work studies the complex behaviour of spinal circuits deprived of voluntary motor control from the brain and in the absence of any other inputs. This is done by describing the monosynaptic responses, polysynaptic activity, and its interaction through its input-output interaction with sustain stimulation that, unlike single stimuli used to study the reflex pathway, can strongly influence the interneuron circuitry and reveal a broader spectrum of connectivity.

Comparison of voice therapy and selective electrical stimulation of the larynx in early unilateral vocal fold paralysis after thyroid surgery: A retrospective data analysis.

OBJECTIVES: The goal of the retrospective study was to investigate the 3-month-outcome after treatment of patients with early unilateral vocal fold paralysis (UVFP) with either standard voice therapy (VT) or selective electrical stimulation of the larynx (SES). DESIGN: Non-randomised retrospective study. SETTING: 1519 patients who underwent thyroid surgery between 2015 and 2018 were analysed according vocal fold mobility; UVFP patients were treated either by VT or SES. PARTICIPANTS: 51 UVFP patients. MAIN OUTCOME MEASURES: 51 UVFP patients have been advised regarding treatment options like either VT (group 1) or SES (group 2). The patients of group 1 (n = 26) and 2 (n = 25) were re-assessed up to 3 months post-operatively regarding UVFP persistence/recovery and perceptive voice sound quality. At follow-ups, perceptual analysis of voice sound (using roughness=R/breathiness=B/hoarseness=H scale) and endoscopic laryngoscopy have been performed. Position of immobile vocal fold, shape of glottal closure and RBH parameters have been considered for statistical analyses. RESULTS: Restitution of UVFP with regular respiratory vocal fold mobility of both vocal folds occurred in 53.8% of group 1 (VT), and in 40.0% of group 2 (SES) after 3 months of therapy between both groups. No difference could be seen for RBH, type of glottal closure and position of ailing vocal folds in patients with persisting UVFP within both groups and between the groups. CONCLUSIONS: The study reveals that SES can achieve similar functional outcome in early UVFP. Thus, it should be considered as an equivalent therapy alternative to VT for treatment of early UVFP patients since no significant difference in vocal outcome and glottal configuration between the two groups could be demonstrated.

Bipolar transcutaneous spinal stimulation evokes short-latency reflex responses in human lower limbs alike standard unipolar electrode configuration.

Noninvasive electrical stimulation targeting the posterior lumbosacral roots has been applied recently in reflexes studies and as a neuromodulation intervention for modifying spinal cord circuitry after an injury. Here, we characterized short-latency responses evoked by four bipolar electrode configurations placed longitudinally over the spinal column at different vertebral levels from L1 to T9. They were compared with the responses evoked by the standard unipolar (aka monopolar) electrode configuration (cathode at T11/12, anode over the abdominal wall). Short-latency responses were recorded in the rectus femoris, medial hamstrings, tibialis anterior, and soleus muscles, bilaterally, in 11 neurologically intact participants. The response recruitment characteristics (maximal amplitude, motor threshold) and amplitude-matched onset latencies and paired-pulse suppression (35-ms interstimulus interval) were assessed with 1-ms current-controlled pulses at intensities up to 100 mA. The results showed that short-latency responses can be elicited with all bipolar electrode configurations. However, only with the cathode at T11/12 and the anode 10 cm cranially (∼T9), the maximum response amplitudes were statistical equivalent (P < 0.05) in the medial hamstrings, tibialis anterior, and soleus but not the rectus femoris, whereas motor thresholds were not significantly different across all muscles. The onset latency and paired-pulse suppression were also not significantly different across the tested electrode configurations, thereby confirming the reflex nature of the bipolar short-latency responses. We conclude that the bipolar configuration (cathode T11/12, anode ∼T9) produces reflex responses that are ostensibly similar to those evoked by the standard unipolar configuration. This provides an alternative approach for neuromodulation intervention.NEW & NOTEWORTHY Transcutaneous spinal stimulation with the identified bipolar electrode configuration may offer several advantages for neuromodulation interventions over commonly used unipolar configurations: there are no associated abdominal contractions, which improves the participant's comfort; additional dermatomes are not stimulated as when the anode is over the abdominal wall or iliac crest, which may have unwanted effects; and, due to a more localized electrical field, the bipolar configuration offers the possibility of targeting cord segments more selectively.

Pull-out forces of headless compression screws in variations of synthetic bone models imitating different types of scaphoid fractures in good bone quality.

Screw osteosynthesis using headless compression screws has become the accepted gold standard for the surgical treatment of scaphoid fractures. Optimal screw specifications remain controversially discussed. We aimed to investigate the influence of bone model composition on screw stability tests using headless compression screws in different scaphoid fracture models. We conducted pull-out tests using Acutrak2®mini, HCS®, HKS®, HBS®, Herbert/Whipple® and Twinfix® screws. To imitate cortical and cancellous bone, two-layer polyurethane (PU) models with two distinct densities were produced. The cylinders were cut at different positions to replicate fracture localisations at increasing distances. The maximum pull-out force required to achieve up to 1 mm of pull-out distance (Nto 1 mm) was measured. Acutrak2®mini and HCS® followed by Twinfix® showed the greatest average pull-out forces. Nto 1 mm was, on average, greater in the cortico-cancellous model than in the cancellous cylinder with the Acutrak2®mini and the Herbert/Whipple® screws, while it was the least with the HBS® and the Twinfix® screws; there were also differences between the HCS® and HKS®. There were no differences between the different fracture simulations in the synthesis strength using either the HKS® or HBS®. The pull-out forces of the HCS® and Twinfix® remained high also in simulations with the smaller screw base fragments. Varying imitations of cancellous and cortico-cancellous bone and fracture localisation reveal important information about the ex vivo strength of screw syntheses. The grip of the cortical structure should be used with the screws that fit more firmly in cortico-cancellous bone.

Objectivation of laryngeal electromyography (LEMG) data: turn number vs. qualitative analysis.

PURPOSE: This paper describes a first attempt to quantify LEMG data based on turn number calculation. The results obtained for both healthy and ailing thyroarytenoid (TA) muscles of patients with unilateral vocal fold immobility (UVFI) were compared with the respective qualitative evaluation concerning volitional activity to determine whether the two types of analyses deliver similar results. METHODS: LEMG data obtained from 44 adults with UVFI were considered for the study. Semiquantitative evaluation of TA volitional activity and turn number were assessed for the ailing and the healthy TA and the difference in percentage was calculated. Paired data were compared with the Wilcoxon signed-rank test. The volitional activity assessment and the turn number evaluation were compared with the Kruskal-Wallis test, and their relationship was tested with the Kendall rank correlation. RESULTS: Datasets of 27 patients were considered compatible with turns/s calculation. The results showed that complete paralysis correlated with no turns; single fiber volitional activity with 62-208 turns/s, strongly decreased volitional activity with 198-501 turns/s; and dense volitional activity with 441-1234 turns/s. On the ailing VF only, the Kruskal-Wallis test showed a statistically significant difference (p = 0.0001), and the Kendall rank correlation a positive relationship (r = 0.853,p ≤ 0.0001) between the volitional activity rating and the turn number assessment. CONCLUSIONS: Our preliminary results showed that turn number evaluation is an effective tool to confirm LEMG qualitative analysis, and that, in combination with laryngostroboscopy and voice assessment, can help improving the accuracy of the diagnosis and prognosis and the effectiveness of the chosen therapy.

Bionic hand as artificial organ: Current status and future perspectives.

Even though the hand comprises only 1% of our body weight, about 30% of our central nervous systems (CNS) capacity is related to its control. The loss of a hand thus presents not only the loss of the most important tool allowing us to interact with our environment, but also leaves a dramatic sensory-motor deficit that challenges our CNS. Reconstruction of hand function is therefore not only an essential part of restoring body integrity and functional wholeness but also closes the loop of our neural circuits diminishing phantom sensation and neural pain. If biology fails to restore meaningful function, today we can resort to complex mechatronic replacement that have functional capabilities that in some respects even outperform biological alternatives, such as hand transplantation. As with replantation and transplantations, the challenge of bionic replacement is connecting the target with the CNS to achieve natural and intuitive control. In recent years, we have developed a number of strategies to improve neural interfacing, signal extraction, interpretation and stable mechanical attachment that are important parts of our current research. This work gives an overview of recent advances in bionic reconstruction, surgical refinements over technological interfacing, skeletal fixation, and modern rehabilitation tools that allow quick integration of prosthetic replacement.

Optimization of Interphase Intervals to Enhance the Evoked Muscular Responses of Transcutaneous Neuromuscular Electrical Stimulation.

Neuromuscular electrical stimulation (NMES) is a widely used technique for clinical diagnostic, treatment, and research. Normally, it applies charge-balanced biphasic pulses, which several publications have reported to be less efficient than monophasic pulses. A good alternative is the use of interphase intervals (IPI) on biphasic pulses that allows to achieve similar responses than those evoked by monophasic stimulation. This study analyzes the enhancing mechanism of the IPI and provides guidelines on how to optimize the IPI in order to reduce secondary effects such as the electrode corrosion. The tibial nerve was excited by NMES biphasic pulses with different IPI durations and polarities. Then, the elicited responses were recorded on the soleus muscle via electromyography. When cathodic-first pulses were applied, the responses increased proportionally to the IPI until the duration of 250 µs, where the increase saturated at 30% of the original amplitude. The responses evoked during anodic-first were 6% to 30% smaller than those evoked during cathodic-first pulses and continuously increased until the IPI duration of 2500 µs, where the responses reached an increase of around 30%. The results suggest that when a cathodic-first pulse is used, the IPI could be optimized (based on the setup geometry) to allow the action potentials to travel out of the hyperpolarization zone induced by the anodic phase. When anodic-first stimuli are applied, the IPI duration allows the fiber to recover from an apparent insensitive state induced by the anodic phase. The use of IPI is a viable option to improve the efficiency of actual stimulation systems, since only small modifications are required to significantly reduce the electrical charge required and boost the stimulation efficiency.

Epidural and transcutaneous spinal electrical stimulation for restoration of movement after incomplete and complete spinal cord injury.

PURPOSE OF REVIEW: The Purpose of this review is to outline and explain the therapeutic use of electrical spinal cord stimulation (SCS) for modification of spinal motor output. Central functional stimulation provides afferent input to posterior root neurons and is applied to improve volitional movements, posture and their endurance, control spasticity, and improve bladder function or perfusion in the lower limbs. Clinical accomplishments strongly depend on each individual's physiological state and specific methodical adaptation to that physiological state. RECENT FINDINGS: Effectiveness of this neuromodulory technique for changing motor control after spinal cord injury (SCI) continues to be explored along with the underlying mechanisms of its effect in people with complete and incomplete spinal cord injuries. There are extensive studies of tonic and rhythmical activity elicited from the lumbar cord as well as data demonstrating augmentation of residual volitional activity. Recent studies have focused on verifying if and how SCS can modify features of neurocontrol in ambulatory spinal cord patients. SUMMARY: In this review, we emphasize recent publications of research revealing that SCS can substitute for the reduced brain drive for control of excitability in people with SCI. Artificially replacing diminished or lost brain control over the spinal cord has limitations. A fundamental requirement for successful SCS application is analysis of each individual's residual postinjury neural function. This will allow a better understanding of the physiological interactions between SCS and spinal cord motor control below injury and provide criteria for its application. Finally, the publication of both successful and failed applications of SCS will be crucial for gaining future progress.

Human spinal locomotor control is based on flexibly organized burst generators.

Constant drive provided to the human lumbar spinal cord by epidural electrical stimulation can cause local neural circuits to generate rhythmic motor outputs to lower limb muscles in people paralysed by spinal cord injury. Epidural spinal cord stimulation thus allows the study of spinal rhythm and pattern generating circuits without their configuration by volitional motor tasks or task-specific peripheral feedback. To reveal spinal locomotor control principles, we studied the repertoire of rhythmic patterns that can be generated by the functionally isolated human lumbar spinal cord, detected as electromyographic activity from the legs, and investigated basic temporal components shared across these patterns. Ten subjects with chronic, motor-complete spinal cord injury were studied. Surface electromyographic responses to lumbar spinal cord stimulation were collected from quadriceps, hamstrings, tibialis anterior, and triceps surae in the supine position. From these data, 10-s segments of rhythmic activity present in the four muscle groups of one limb were extracted. Such samples were found in seven subjects. Physiologically adequate cycle durations and relative extension- and flexion-phase durations similar to those needed for locomotion were generated. The multi-muscle activation patterns exhibited a variety of coactivation, mixed-synergy and locomotor-like configurations. Statistical decomposition of the electromyographic data across subjects, muscles and samples of rhythmic patterns identified three common temporal components, i.e. basic or shared activation patterns. Two of these basic patterns controlled muscles to contract either synchronously or alternatingly during extension- and flexion-like phases. The third basic pattern contributed to the observed muscle activities independently from these extensor- and flexor-related basic patterns. Each bifunctional muscle group was able to express both extensor- and flexor-patterns, with variable ratios across the samples of rhythmic patterns. The basic activation patterns can be interpreted as central drives implemented by spinal burst generators that impose specific spatiotemporally organized activation on the lumbosacral motor neuron pools. Our data thus imply that the human lumbar spinal cord circuits can form burst-generating elements that flexibly combine to obtain a wide range of locomotor outputs from a constant, repetitive input. It may be possible to use this flexibility to incorporate specific adaptations to gait and stance to improve locomotor control, even after severe central nervous system damage.

Motor Control of Human Spinal Cord Disconnected from the Brain and Under External Movement.

Motor control after spinal cord injury is strongly depending on residual ascending and descending pathways across the lesion. The individually altered neurophysiology is in general based on still intact sublesional control loops with afferent sensory inputs linked via interneuron networks to efferent motor outputs. Partial or total loss of translesional control inputs reduces and alters the ability to perform voluntary movements and results in motor incomplete (residual voluntary control of movement functions) or motor complete (no residual voluntary control) spinal cord injury classification. Of particular importance are intact functionally silent neural structures with residual brain influence but reduced state of excitability that inhibits execution of voluntary movements. The condition is described by the term discomplete spinal cord injury. There are strong evidences that artificial afferent input, e.g., by epidural or noninvasive electrical stimulation of the lumbar posterior roots, can elevate the state of excitability and thus re-enable or augment voluntary movement functions. This modality can serve as a powerful assessment technique for monitoring details of the residual function profile after spinal cord injury, as a therapeutic tool for support of restoration of movement programs and as a neuroprosthesis component augmenting and restoring movement functions, per se or in synergy with classical neuromuscular or muscular electrical stimulation.

Periodic modulation of repetitively elicited monosynaptic reflexes of the human lumbosacral spinal cord.

In individuals with motor-complete spinal cord injury, epidural stimulation of the lumbosacral spinal cord at 2 Hz evokes unmodulated reflexes in the lower limbs, while stimulation at 22-60 Hz can generate rhythmic burstlike activity. Here we elaborated on an output pattern emerging at transitional stimulation frequencies with consecutively elicited reflexes alternating between large and small. We analyzed responses concomitantly elicited in thigh and leg muscle groups bilaterally by epidural stimulation in eight motor-complete spinal cord-injured individuals. Periodic amplitude modulation of at least 20 successive responses occurred in 31.4% of all available data sets with stimulation frequency set at 5-26 Hz, with highest prevalence at 16 Hz. It could be evoked in a single muscle group only but was more strongly expressed and consistent when occurring in pairs of antagonists or in the same muscle group bilaterally. Latencies and waveforms of the modulated reflexes corresponded to those of the unmodulated, monosynaptic responses to 2-Hz stimulation. We suggest that the cyclical changes of reflex excitability resulted from the interaction of facilitatory and inhibitory mechanisms emerging after specific delays and with distinct durations, including postactivation depression, recurrent inhibition and facilitation, as well as reafferent feedback activation. The emergence of large responses within the patterns at a rate of 5.5/s or 8/s may further suggest the entrainment of spinal mechanisms as involved in clonus. The study demonstrates that the human lumbosacral spinal cord can organize a simple form of rhythmicity through the repetitive activation of spinal reflex circuits.

Neurocontrol of Movement in Humans With Spinal Cord Injury.

In this review of neurocontrol of movement after spinal cord injury, we discuss neurophysiological evidences of conducting and processing mechanisms of the spinal cord. We illustrate that external afferent inputs to the spinal cord below the level of the lesion can modify, initiate, and maintain execution of movement in absence or partial presence of brain motor control after chronic spinal cord injury. We review significant differences between spinal reflex activity elicited by single and repetitive stimulation. The spinal cord can respond with sensitization, habituation, and dis-habituation to regular repetitive stimulation. Therefore, repetitive spinal cord reflex activity can contribute to the functional configuration of the spinal network. Moreover, testing spinal reflex activity in individuals with motor complete spinal cord injury provided evidences for subclinical residual brain influence, suggesting the existence of axons traversing the injury site and influencing the activities below the level of lesion. Thus, there are two motor control models of chronic spinal cord injury in humans: "discomplete" and "reduced and altered volitional motor control." We outline accomplishments in modification and initiation of altered neurocontrol in chronic spinal cord injury people with epidural and functional electrical stimulation. By nonpatterned electrical stimulation of lumbar posterior roots, it is possible to evoke bilateral extension as well as rhythmic motor outputs. Epidural stimulation during treadmill stepping shows increased and/or modified motor activity. Finally, volitional efforts can alter epidurally induced rhythmic activities in incomplete spinal cord injury. Overall, we highlight that upper motor neuron paralysis does not entail complete absence of connectivity between cortex, brain stem, and spinal motor cells, but there can be altered anatomy and corresponding neurophysiological characteristics. With specific input to the spinal cord below the level of the lesion, the clinical status of upper motor neuron paralysis without structural modification can be modified, and movements can be initiated. Thus, external afferent input can partially replace brain control.

In Vitro Testing of an Implantable Wireless Telemetry System for Long-Term Electromyography Recordings in Large Animals.

Multichannel bio-signal recording in undisturbed in vivo conditions is a frequent demand in experimental work for development of methodology and associated equipment for functional electrical stimulation (FES) application, limb prosthesis, and diagnostic tools in contemporary rehabilitation efforts. Intramuscular electromyogram (EMG) recordings can provide comprehensive insight in complex interactions of agonistic and antagonistic muscles during movement tasks and in contrast act as reliable control signals for both neuroprosthesis and mechanical prosthesis. We fabricated a fully implantable device, which is capable of recording electromyography signals from inside a body and transmit these signals wirelessly to an external receiver. The developed analog front end uses only two electrodes per channel, provides a gain of 60 dB, and incorporates a band pass filter with lower cut-off frequency of 4 Hz and upper cut-off frequency of 480 Hz. The bidirectional wireless data link, which operates in the 2.4 GHz Industrial, Scientific and Medical band, is designed for transmission distances of 10 m using an application data rate of 1 kSps for each of the two channels. Performed in vitro tests with the devices coated in epoxy resin and inserted into a phantom with tissue-equivalent characteristics confirmed the functionality of our concept and the measurement results are consistent with those from preceding simulations.

Multi-Electrode Array for Transcutaneous Lumbar Posterior Root Stimulation.

Interest in transcutaneous electrical stimulation of the lumbosacral spinal cord is increasing in human electrophysiological and clinical studies. The stimulation effects on lower limb muscles depend on the depolarization of segmentally organized posterior root afferents and, thus, the rostro-caudal stimulation site. In previous studies, selective stimulation was achieved by varying the positions of single self-adhesive electrodes over the thoracolumbar spine. Here, we developed a multi-electrode surface array consisting of 3 × 8 electrode pads and tested its stimulation-site specificity. The array was placed longitudinally over the spine covering the T10-L2 vertebrae. Two different hydrogel layer configurations were utilized: a single layer adhered to all electrode pads of the array and a configuration comprised of eight separate strips attached to the three transverse electrode pads of each level. Voltage measurements demonstrated that an effectively focused field distribution along the longitudinal extent of the array was not accomplished when using the single continuous hydrogel layer, and segmental selective stimulation of the posterior root afferents was not possible. The separate strips produced a focused electric field distribution at the rostro-caudal level of the electrode pads selected for stimulation. This configuration allowed for the preferential elicitation of posterior root-muscle reflexes in either the L2-L4 innervated quadriceps or the L5-S2 innervated triceps surae muscle groups. Such multi-electrode array for transcutaneous spinal cord stimulation shall allow for improved control of stimulation conditions in electrophysiological studies and time-dependent and site-specific stimulation patterns for neuromodulation applications.

Comparison of Twitch Responses During Current- or Voltage-Controlled Transcutaneous Neuromuscular Electrical Stimulation.

Neuromuscular electrical stimulation (NMES) is an established method for functional restoration of muscle function, rehabilitation, and diagnostics. In this work, NMES was applied with surface electrodes placed on the anterior thigh to identify the main differences between current-controlled (CC) and voltage-controlled (VC) modes. Measurements of the evoked knee extension force and the myoelectric signal of quadriceps and hamstrings were taken during stimulation with different amplitudes, pulse widths, and stimulation techniques. The stimulation pulses were rectangular and symmetric biphasic for both stimulation modes. The electrode-tissue impedance influences the differences between CC and VC stimulation. The main difference is that for CC stimulation, variation of pulse width and amplitude influences the amount of nerve depolarization, whereas VC stimulation is only dependent on amplitude variations for pulse widths longer than 150 µs. An important remark is that these findings are strongly dependent on the characteristics of the electrode-skin interface. In our case, we used large stimulation electrodes placed on the anterior thigh, which cause higher capacitive effects. The controllability, voltage compliance, and charge characteristics of each stimulation technique should be considered during the stimulators design. For applications that require the activation of a large amount of nerve fibers, VC is a more suitable option. In contrast, if the application requires a high controllability, then CC should be chosen prior to VC.

Augmentation of Voluntary Locomotor Activity by Transcutaneous Spinal Cord Stimulation in Motor-Incomplete Spinal Cord-Injured Individuals.

The level of sustainable excitability within lumbar spinal cord circuitries is one of the factors determining the functional outcome of locomotor therapy after motor-incomplete spinal cord injury. Here, we present initial data using noninvasive transcutaneous lumbar spinal cord stimulation (tSCS) to modulate this central state of excitability during voluntary treadmill stepping in three motor-incomplete spinal cord-injured individuals. Stimulation was applied at 30 Hz with an intensity that generated tingling sensations in the lower limb dermatomes, yet without producing muscle reflex activity. This stimulation changed muscle activation, gait kinematics, and the amount of manual assistance required from the therapists to maintain stepping with some interindividual differences. The effect on motor outputs during treadmill-stepping was essentially augmentative and step-phase dependent despite the invariant tonic stimulation. The most consistent modification was found in the gait kinematics, with the hip flexion during swing increased by 11.3° ± 5.6° across all subjects. This preliminary work suggests that tSCS provides for a background increase in activation of the lumbar spinal locomotor circuitry that has partially lost its descending drive. Voluntary inputs and step-related feedback build upon the stimulation-induced increased state of excitability in the generation of locomotor activity. Thus, tSCS essentially works as an electrical neuroprosthesis augmenting remaining motor control.

Modification of spasticity by transcutaneous spinal cord stimulation in individuals with incomplete spinal cord injury.

CONTEXT/OBJECTIVE: To examine the effects of transcutaneous spinal cord stimulation (tSCS) on lower-limb spasticity. DESIGN: Interventional pilot study to produce preliminary data. SETTING: Department of Physical Medicine and Rehabilitation, Wilhelminenspital, Vienna, Austria. PARTICIPANTS: Three subjects with chronic motor-incomplete spinal cord injury (SCI) who could walk ≥10 m. INTERVENTIONS: Two interconnected stimulating skin electrodes (Ø 5 cm) were placed paraspinally at the T11/T12 vertebral levels, and two rectangular electrodes (8 × 13 cm) on the abdomen for the reference. Biphasic 2 ms-width pulses were delivered at 50 Hz for 30 minutes at intensities producing paraesthesias but no motor responses in the lower limbs. OUTCOME MEASURES: The Wartenberg pendulum test and neurological recordings of surface-electromyography (EMG) were used to assess effects on exaggerated reflex excitability. Non-functional co-activation during volitional movement was evaluated. The timed 10-m walk test provided measures of clinical function. RESULTS: The index of spasticity derived from the pendulum test changed from 0.8 ± 0.4 pre- to 0.9 ± 0.3 post-stimulation, with an improvement in the subject with the lowest pre-stimulation index. Exaggerated reflex responsiveness was decreased after tSCS across all subjects, with the most profound effect on passive lower-limb movement (pre- to post-tSCS EMG ratio: 0.2 ± 0.1), as was non-functional co-activation during voluntary movement. Gait speed values increased in two subjects by 39%. CONCLUSION: These preliminary results suggest that tSCS, similar to epidurally delivered stimulation, may be used for spasticity control, without negatively impacting residual motor control in incomplete SCI. Further study in a larger population is warranted.

The Effect of Photobiomodulation on Bone Mineral Density, Serum Vitamin D, and Bone Formation Markers in Individuals with Complete Spinal Cord Injuries with Osteoporosis.

Study design: A quasi-experimental study utilized a matched-pair design, administering photobiomodulation at four-sites on one side of the body and assigning control to the other side at corresponding sites. Objectives: This study aimed to assess photobiomodulation treatment effects on bone mineral density (BMD) measurement using dual-energy X-ray-absorptiometry in individuals with complete spinal cord injury (C.SCI) and osteoporosis. Methods: Eight patients received treatment at four-sites: forearm-mid-distal (MID), proximal-femur, distal-femur, and proximal-tibia, totaling 32 sites. Using an 830 nm gallium-aluminum-arsenide semiconductor laser irradiation was administered three times weekly for 8 weeks. Different doses (energy density) were determined depending on bone depth from skin surface, as assessed by sonography and adjusted through irradiation time to be 8, 10, and 12 J/cm2 for depths <1 cm, between 1 and 1.5 cm, and >1.5 cm, respectively, using 200 mW power to deliver the optimal isodose of laser at each depth of bone within each therapeutic site. BMD was measured at baseline, week 8 of treatment, and week 15 of follow-up. Serum 25-(OH)-vitamin D and bone formation markers including osteocalcin and bone-alkaline-phosphatase (B-ALP) were also assessed at baseline and week 8 of treatment. Results: Significant increases in BMD were noted in proximal-femur and forearm-MID at both week 8 and week 15. Serum 25-(OH)-vitamin D levels significantly increased after treatment. However, no notable changes were observed in distal-femur and proximal-tibia BMD or in osteocalcin and B-ALP levels. Conclusions: Photobiomodulation (830 nm) laser demonstrated efficacy in improving BMD at proximal-femur and forearm-MID in individuals with C.SCI. Moreover, the observed positive influence on vitamin D levels suggests a potential photobiomodulation role, warranting further investigation.

Dirk Pette, remembered for his pioneering muscle research.

It is with great sadness that we learned of the passing of Prof. Dr. Dr. h.c. Dirk Pette. He passed away suddenly and unexpectedly on June 4, 2022. Dirk was an outstanding professor of biochemistry at the University of Konstanz, Germany and an internationally renowned researcher in the field of skeletal muscle biology. His research on electrical stimulation has had a profound impact on our understanding of myofiber type specification and the enormous adaptive potential of skeletal muscle. Under Dirk's leadership, new biological questions in the field of neuromuscular biology have developed into multidisciplinary approaches using advanced physiological, cell biological, and biochemical techniques. Dirk's research laboratory was frequently visited by a large number of national and international collaborators who familiarized themselves with the technically demanding stimulation protocols and bioanalytical techniques to study the intricate details of the highly complex process of fast-to-slow muscle transitions. Importantly, fundamental studies on the physiological effects of changes in innervation patterns on muscle phenotype have provided the scientific evidence base for a variety of innovative clinical applications. The skeletal muscle research community has lost one of its leading figures and an outstanding teacher of protein biochemistry. He leaves an inspiring legacy in the field of basic and applied myology. Dirk will be missed by his colleagues and by many students of neuromuscular biology and beyond.