Soleus H-Reflex Modulation After Motor Incomplete Spinal Cord Injury: Effects of Body Position and Walking Speed

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.

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Stabilization Strategies for Fast Walking in Challenging Environments With Incomplete Spinal Cord Injury

Frontiers in Rehabilitation Sciences ◽

10.3389/fresc.2021.709420 ◽

2021 ◽

Vol 2 ◽

Author(s):

Tara Cornwell ◽

Jane Woodward ◽

Wendy Ochs ◽

Keith E. Gordon

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Walking Speed ◽

Center Of Mass ◽

Lateral Stability ◽

Step Width ◽

Incomplete Spinal Cord Injury ◽

Foot Placement ◽

Fast Speed ◽

Cord Injury

Gait rehabilitation following incomplete spinal cord injury (iSCI) often aims to enhance speed and stability. Concurrently increasing both may be difficult though as certain stabilization strategies will be compromised at faster speeds. To evaluate the interaction between speed and lateral stability, we examined individuals with (n = 12) and without (n = 12) iSCI as they performed straight walking and lateral maneuvers at Preferred and Fast treadmill speeds. To better detect the effects of speed on stability, we challenged lateral stability with a movement amplification force field. The Amplification field, created by a cable-driven robot, applied lateral forces to the pelvis that were proportional to the real-time lateral center of mass (COM) velocity. While we expected individuals to maintain stability during straight walking at the Fast speed in normal conditions, we hypothesized that both groups would be less stable in the Amplification field at the Fast speed compared to the Preferred. However, we found no effects of speed or the interaction between speed and field on straight-walking stability [Lyapunov exponent or lateral margin of stability (MOS)]. Across all trials at the Fast speed compared to the Preferred, there was greater step width variability (p = 0.031) and a stronger correlation between lateral COM state at midstance and the subsequent lateral foot placement. These observations suggest that increased stepping variability at faster speeds may be beneficial for COM control. We hypothesized that during lateral maneuvers in the Amplification field, MOS on the Initiation and Termination steps would be smaller at the Fast speed than at the Preferred. We found no effect of speed on the Initiation step MOS within either field (p > 0.350) or group (p > 0.200). The Termination step MOS decreased at the Fast speed within the group without iSCI (p < 0.001), indicating a trade-off between lateral stability and forward walking speed. Unexpectedly, participants took more steps and time to complete maneuvers at the Fast treadmill speed in the Amplification field. This strategy prioritizing stability over speed was especially evident in the group with iSCI. Overall, individuals with iSCI were able to maintain lateral stability when walking fast in balance-challenging conditions but may have employed more cautious maneuver strategies.

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Electrophysiological outcomes after spinal cord injury

Neurosurgical FOCUS ◽

10.3171/foc.2008.25.11.e11 ◽

2008 ◽

Vol 25 (5) ◽

pp. E11 ◽

Cited By ~ 15

Author(s):

James Xie ◽

Maxwell Boakye

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Evoked Potentials ◽

Somatosensory Evoked Potentials ◽

Motor Evoked Potential ◽

H Reflex ◽

Sensory Function ◽

Reflex Modulation ◽

Clinical Evaluations ◽

Cord Injury

Electrophysiological measures can provide information that complements clinical assessments such as the American Spinal Injury Association sensory and motor scores in the evaluation of outcomes after spinal cord injury (SCI). The authors review and summarize the literature regarding tests that are most relevant to the study of SCI recovery—in particular, motor evoked potentials and somatosensory evoked potentials (SSEPs). In addition, they discuss the role of other tests, including F-wave nerve conductance tests and electromyography, sympathetic skin response, and the Hoffman reflex (H-reflex) test as well as the promise of dermatomal SSEPs and the electrical perceptual threshold test, newer quantitative tests of sensory function. It has been shown that motor evoked potential amplitudes improve with SCI recovery but latencies do not. Somatosensory evoked potentials are predictive of ambulatory capacity and hand function. Hoffman reflexes are present during spinal shock despite the loss of tendon reflexes, but their amplitudes increase with time after injury. Further, H-reflex modulation is reflective of changes in spinal excitability. While these tests have produced data that is congruent with clinical evaluations, they have yet to surpass clinical evaluations in predicting outcomes. Continuing research using these methodologies should yield a better understanding of the mechanisms behind SCI recovery and thus provide potentially greater predictive and evaluative power.

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Assessment of Walking Speed and Distance in Subjects With an Incomplete Spinal Cord Injury

Neurorehabilitation and Neural Repair ◽

10.1177/1545968306297861 ◽

2007 ◽

Vol 21 (4) ◽

pp. 295-301 ◽

Cited By ~ 62

Author(s):

Hubertus J. A. van Hedel ◽

Volker Dietz ◽

Armin Curt

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Walking Speed ◽

Incomplete Spinal Cord Injury ◽

Cord Injury

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Effect of Treadmill Training on Gait and Functional Independence in Patients with Incomplete Spinal Cord Injury: A Case Series

Internet Journal of Allied Health Sciences and Practice ◽

10.46743/1540-580x/2012.1409 ◽

2012 ◽

Author(s):

Shahnawaz Anwer ◽

Ameed Equebal ◽

Ratnesh Kumar

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Walking Speed ◽

Case Series ◽

Gait Training ◽

Functional Independence ◽

Treadmill Training ◽

Incomplete Spinal Cord Injury ◽

Post Injury ◽

Cord Injury

Background and purpose: Many individuals with an incomplete spinal cord injury (SCI) have the potential to walk. The effectiveness of using a treadmill for gait training for these patients has been substantiated in the literature. This case series describes the effectiveness of incorporating gait training on a treadmill for two individuals with an incomplete SCI. Case Description: The treatments of two males each with an incomplete paraplegia were described. Subject 1 was 40 years old and was 14 months post injury at the time of the study. He had a T6 incomplete spinal cord injury classified as a D on the American Spinal Injury Association (ASIA) Impairment Scale and neurological classification standards. Subject 2 was 48 years old and was 10 months post injury. He had a T8 incomplete spinal cord injury classified as ASIA C. Intervention: Both subjects participated in gait training for a maximum of 10 minutes on a motorized treadmill without elevation at a comfortable walking speed three days a week for four weeks as an adjunct to a conventional physiotherapy programme.Results: An increase in step length, stride length, cadence, and comfortable walking speed were noted in both subjects. Both subjects improved their walking level as measured by the Walking Index for Spinal Cord Injury (WISCI II) and functional independence as measured by Spinal Cord Independent Measure (SCIM II). Conclusion: Gait training on a treadmill can improve gait parameters and functional independence in patients with incomplete paraplegia. Further research is needed to improve the generalizability of these findings and to identify which patients might benefit most from treadmill training.

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