scholarly journals Transcutaneous spinal cord stimulation of the cervical cord modulates lumbar networks

2020 ◽  
Vol 123 (1) ◽  
pp. 158-166 ◽  
Author(s):  
Trevor S. Barss ◽  
Behdad Parhizi ◽  
Vivian K. Mushahwar
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Stimulation ◽  
Cervical Spinal Cord ◽  
H Reflex ◽  
Cervical Cord ◽  
Arm Cycling ◽  
Cord Injury ◽  
Walking Capacity ◽  
Transcutaneous Spinal Cord Stimulation ◽  
Lumbar Cord

It has been established that coordinated arm and leg (A&L) cycling facilitates corticospinal drive and modulation of cervico-lumbar connectivity and ultimately improves overground walking in people with incomplete spinal cord injury or stroke. This study examined the effect of noninvasive transcutaneous spinal cord stimulation (tSCS) on the modulation of cervico-lumbar connectivity. Thirteen neurologically intact adults participated in the study. The excitability of the Hoffmann (H) reflex elicited in the soleus muscle was examined under multiple conditions involving either the arms held in a static position or rhythmic arm cycling while tSCS was applied to either the cervical or lumbar cord. As expected, soleus H-reflex amplitude was significantly suppressed by 19.2% during arm cycling (without tSCS) relative to arms static (without tSCS). Interestingly, tSCS of the cervical cord with arms static significantly suppressed the soleus H-reflex (−22.9%), whereas tSCS over the lumbar cord did not suppress the soleus H-reflex (−3.8%). The combination of arm cycling with cervical or lumbar tSCS did not yield additional suppression of the soleus H-reflex beyond that obtained with arm cycling alone or cervical tSCS alone. The results demonstrate that activation of the cervical spinal cord through both rhythmic arm cycling and tonic tSCS significantly modulates the activity of lumbar networks. This highlights the potential for engaging cervical spinal cord networks through tSCS during rehabilitation interventions to enhance cervico-lumbar connectivity. This connectivity is influential in facilitating improvements in walking function after neurological impairment. NEW & NOTEWORTHY This is the first study to investigate the modulatory effects of transcutaneous spinal cord stimulation (tSCS) on cervico-lumbar connectivity. We report that both rhythmic activation of the cervical spinal cord through arm cycling and tonic activation of the cervical cord through tSCS significantly modulate the activity of lumbar networks. This suggests that engaging cervical spinal cord networks through tSCS during locomotor retraining interventions may not only enhance cervico-lumbar connectivity but also further improve walking capacity.

scholarly journals Posteroanterior Cervical Transcutaneous Spinal Cord Stimulation: Interactions with Cortical and Peripheral Nerve Stimulation

2021 ◽  
Vol 10 (22) ◽  
pp. 5304
Author(s):  
Jaclyn R. Wecht ◽  
William M. Savage ◽  
Grace O. Famodimu ◽  
Gregory A. Mendez ◽  
Jonah M. Levine ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Motor Cortex ◽  
Motor Neurons ◽  
Nerve Stimulation ◽  
Spinal Cord Stimulation ◽  
Cervical Spinal Cord ◽  
Hand Function ◽  
Median Nerve Stimulation ◽  
Cord Injury ◽  
Transcutaneous Spinal Cord Stimulation

Transcutaneous spinal cord stimulation (TSCS) has demonstrated potential to beneficially modulate spinal cord motor and autonomic circuitry. We are interested in pairing cervical TSCS with other forms of nervous system stimulation to enhance synaptic plasticity in circuits serving hand function. We use a novel configuration for cervical TSCS in which the anode is placed anteriorly over ~C4–C5 and the cathode posteriorly over ~T2–T4. We measured the effects of single pulses of TSCS paired with single pulses of motor cortex or median nerve stimulation timed to arrive at the cervical spinal cord at varying intervals. In 13 participants with and 15 participants without chronic cervical spinal cord injury, we observed that subthreshold TSCS facilitates hand muscle responses to motor cortex stimulation, with a tendency toward greater facilitation when TSCS is timed to arrive at cervical synapses simultaneously or up to 10 milliseconds after cortical stimulus arrival. Single pulses of subthreshold TSCS had no effect on the amplitudes of median H-reflex responses or F-wave responses. These findings support a model in which TSCS paired with appropriately timed cortical stimulation has the potential to facilitate convergent transmission between descending motor circuits, segmental afferents, and spinal motor neurons serving the hand. Studies with larger numbers of participants and repetitively paired cortical and spinal stimulation are needed.

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

2013 ◽  
Vol 37 (2) ◽  
pp. 202-211 ◽  
Author(s):  
Ursula S. Hofstoetter ◽  
William B. McKay ◽  
Keith E. Tansey ◽  
Winfried Mayr ◽  
Helmut Kern ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Spinal Cord Stimulation ◽  
Incomplete Spinal Cord Injury ◽  
Cord Injury ◽  
Transcutaneous Spinal Cord Stimulation

scholarly journals Effect of cervicolumbar coupling on spinal reflexes during cycling after incomplete spinal cord injury

2018 ◽  
Vol 120 (6) ◽  
pp. 3172-3186 ◽  
Author(s):  
R. Zhou ◽  
B. Parhizi ◽  
J. Assh ◽  
L. Alvarado ◽  
R. Ogilvie ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
H Reflex ◽  
Spinal Reflexes ◽  
Incomplete Spinal Cord Injury ◽  
Reflex Amplitude ◽  
Arm Cycling ◽  
Cord Injury ◽  
Leg Cycling ◽  
Cycling Training

Spinal networks in the cervical and lumbar cord are actively coupled during locomotion to coordinate arm and leg activity. The goals of this project were to investigate the intersegmental cervicolumbar connectivity during cycling after incomplete spinal cord injury (iSCI) and to assess the effect of rehabilitation training on improving reflex modulation mediated by cervicolumbar pathways. Two studies were conducted. In the first, 22 neurologically intact (NI) people and 10 people with chronic iSCI were recruited. The change in H-reflex amplitude in flexor carpi radialis (FCR) during leg cycling and H-reflex amplitude in soleus (SOL) during arm cycling were investigated. In the second study, two groups of participants with chronic iSCI underwent 12 wk of cycling training: one performed combined arm and leg cycling (A&L) and the other legs only cycling (Leg). The effect of training paradigm on the amplitude of the SOL H-reflex was assessed. Significant reduction in the amplitude of both FCR and SOL H-reflexes during dynamic cycling of the opposite limbs was found in NI participants but not in participants with iSCI. Nonetheless, there was a significant reduction in the SOL H-reflex during dynamic arm cycling in iSCI participants after training. Substantial improvements in SOL H-reflex properties were found in the A&L group after training. The results demonstrate that cervicolumbar modulation during rhythmic movements is disrupted in people with chronic iSCI; however, this modulation is restored after cycling training. Furthermore, involvement of the arms simultaneously with the legs during training may better regulate the leg spinal reflexes.NEW & NOTEWORTHY This work systematically demonstrates the disruptive effect of incomplete spinal cord injury on cervicolumbar coupling during rhythmic locomotor movements. It also shows that the impaired cervicolumbar coupling could be significantly restored after cycling training. Actively engaging the arms in rehabilitation paradigms for the improvement of walking substantially regulates the excitability of the lumbar spinal networks. The resulting regulation may be better than that obtained by interventions that focus on training of the legs only.

Intubation Biomechanics: Clinical Implications of Computational Modeling of Intervertebral Motion and Spinal Cord Strain during Tracheal Intubation in an Intact Cervical Spine

2021 ◽  
Author(s):  
Benjamin C. Gadomski ◽  
Bradley J. Hindman ◽  
Mitchell I. Page ◽  
Franklin Dexter ◽  
Christian M. Puttlitz
Keyword(s):  
Spinal Cord ◽  
Cervical Spine ◽  
Tracheal Intubation ◽  
Cervical Spinal Cord ◽  
Maximum Force ◽  
Cervical Cord ◽  
Injury Threshold ◽  
Force Magnitude ◽  
Cord Injury ◽  
Cervical Motion

Background In a closed claims study, most patients experiencing cervical spinal cord injury had stable cervical spines. This raises two questions. First, in the presence of an intact (stable) cervical spine, are there tracheal intubation conditions in which cervical intervertebral motions exceed physiologically normal maximum values? Second, with an intact spine, are there tracheal intubation conditions in which potentially injurious cervical cord strains can occur? Methods This study utilized a computational model of the cervical spine and cord to predict intervertebral motions (rotation, translation) and cord strains (stretch, compression). Routine (Macintosh) intubation force conditions were defined by a specific application location (mid-C3 vertebral body), magnitude (48.8 N), and direction (70 degrees). A total of 48 intubation conditions were modeled: all combinations of 4 force locations (cephalad and caudad of routine), 4 magnitudes (50 to 200% of routine), and 3 directions (50, 70, and 90 degrees). Modeled maximum intervertebral motions were compared to motions reported in previous clinical studies of the range of voluntary cervical motion. Modeled peak cord strains were compared to potential strain injury thresholds. Results Modeled maximum intervertebral motions occurred with maximum force magnitude (97.6 N) and did not differ from physiologically normal maximum motion values. Peak tensile cord strains (stretch) did not exceed the potential injury threshold (0.14) in any of the 48 force conditions. Peak compressive strains exceeded the potential injury threshold (–0.20) in 3 of 48 conditions, all with maximum force magnitude applied in a nonroutine location. Conclusions With an intact cervical spine, even with application of twice the routine value of force magnitude, intervertebral motions during intubation did not exceed physiologically normal maximum values. However, under nonroutine high-force conditions, compressive strains exceeded potentially injurious values. In patients whose cords have less than normal tolerance to acute strain, compressive strains occurring with routine intubation forces may reach potentially injurious values. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

scholarly journals Buspirone Dose-Response on Facilitating Forelimb Functional Recovery in Cervical Spinal Cord Injured Rats

Dose-Response ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 155932582199813
Author(s):  
Rakib Uddin Ahmed ◽  
V. Reggie Edgerton ◽  
Shuai Li ◽  
Yong-Ping Zheng ◽  
Monzurul Alam
Keyword(s):  
Spinal Cord ◽  
Grip Strength ◽  
Dose Response ◽  
Cervical Spinal Cord ◽  
Dose Dependence ◽  
Dorsal Column ◽  
Cervical Cord ◽  
Sprague Dawley ◽  
Post Injury ◽  
Cord Injury

Buspirone, widely used as a neuropsychiatric drug, has also shown potentials for motor function recovery of injured spinal cord. However, the optimum dosages of such treatment remain unclear. In this study, we investigated the dose-response of Buspirone treatment on reaching and grasping function in cervical cord injured rats. Seventeen adult Sprague-Dawley rats were trained to reach and grasp sugar pellets before a C4 bilateral dorsal column crush injury. After 1 week post-injury, the rats were divided into 3 groups to receive 1 of 3 different dosages of Buspirone (i.p., 1 dose/day: 1.5, n = 5; 2.5, n = 6 and 3.5 mg/kg b.w., n = 6). Forelimb reaching and grip strength test were recorded once per week, within 1 hour of Buspirone administration for 11 weeks post-injury. Different dose groups began to exhibit differences in reaching scores from 4 weeks post-injury. From 4-11 weeks post-injury, the reaching scores were highest in the lowest-dose group rats compared to the other 2 dose groups rats. Average grip strength was also found higher in the lowest-dose rats. Our results demonstrate a significant dose-dependence of Buspirone on the recovery of forelimb motor functions after cervical cord injury with the best performance occurring at the lowest dose tested.

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