Spastic Reflexes Triggered by Ankle Load Release in Human Spinal Cord Injury

Wu, Ming; Schmit, Brian D.

doi:10.1152/jn.00186.2006

Cited by 17 publications

(12 citation statements)

References 42 publications

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“…For instance, hip or knee extension alone or simultaneous hip and knee extension triggered a multijoint response that included prominent activity in the SOL, which is not stretched or shortened by the imposed knee and hip movements. These results are consistent with previous studies indicating that subjects with chronic SCI produce multijoint reflex responses to single joint movements at other joints, such as flexor reflexes triggered by movement of the ankle [17] and knee joints [18] and extensor reflexes triggered by movement of the hip or knee [3][4]. The multijoint nature of these reflex responses supports the notion that spastic reflexes in chronic SCI can be attributed, at least in part, to an increased excitability in the coupling between specific modules within the spinal cord.…”

Section: Role Of Interneuronal Excitability In Sci Spasticitysupporting

confidence: 93%

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Reflex responses to combined hip and knee motion in human chronic spinal cord injury

Wu¹,

Schmit²

2010

JRRD

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Abstract-The relative contributions of hip and knee proprioceptors to the origination of extensor spasms were examined in 11 subjects with chronic spinal cord injury (SCI). Ramp and hold extension and combined hip and knee oscillation movements were imposed to the right leg while the ankle was held in a static position by a custom-designed robot. Isometric joint torques of the hip, knee, and ankle and surface electromyograms (EMGs) from seven leg muscles were recorded following controlled hip and knee extension. A stereotypical torque response consisting of hip flexion, knee extension, and ankle plantar flexion was observed following hip and knee perturbations. Further, the hip or knee joint posture modulated the spastic reflexes triggered by the extension movement of the other joint, with larger responses observed with the hip and knee extended. In addition, combined hip and knee oscillation movements were imposed to one leg with four different phasing conditions. The phasing between the hip and knee modulated the reflex activity triggered by hip and knee oscillations. The EMG patterns of the spastic reflexes were generally consistent with muscle timing during locomotion in human SCI. This knowledge may help identify rehabilitation strategies that produce functional movements in human SCI.

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Section: Role Of Interneuronal Excitability In Sci Spasticitysupporting

confidence: 93%

“…Similarly, ankle load release, which produces a similar reflex response as hip stretch in animals models [37][38], also produces extensor spasms with increased VM activity in human SCI [18].…”

Section: Involvement Of Locomotor Pathways In the Reflexes Triggered mentioning

confidence: 93%

Reflex responses to combined hip and knee motion in human chronic spinal cord injury

Wu¹,

Schmit²

2010

JRRD

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“…The reliance on hip torque to power walking relative to knee and ankle torque may be increased in SCI subjects similar to the changes observed in stroke (Nadeau et al 1999) and elderly populations (DeVita and Hortobagyi 2000). Several studies have shown that in human SCI subjects, modulating load at the ankle joint can trigger and/or enhance hip movements (Schmit et al 2000Wu and Schmit 2006). Similarly, during fictive locomotion, stimulation of the group I ankle extensor afferents during bursting results in an increase in amplitude and duration of ipsilateral ankle, knee, and hip extensor activity (Guertin et al 1995).…”

Section: Introductionmentioning

confidence: 79%

“…This polysynaptic reflex response is believed to be mediated through similar neural pathways as those associated with reflex control of locomotion. Of interest is that this hip flexion reflex response can be enhanced in SCI subjects by removing a dorsiflexor ankle torque immediately following hip extension in a manner analogous to the limb unloading that occurs during the late stance phase of gait (Wu and Schmit 2006). These studies provide evidence that complex responses can be produced by sensory cues typically attributed to reflex regulation of locomotion in human SCI; however, the direct effects on stepping are unknown.…”

Section: Introductionmentioning

confidence: 99%

Ankle Load Modulates Hip Kinetics and EMG During Human Locomotion

Gordon¹,

Wu²,

Kahn³

et al. 2009

Journal of Neurophysiology

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“…In addition, the enhanced load afferents from the ipsilateral leg, that is, standing leg, may facilitate load release from the contralateral leg, that is, the swing leg. The load release information from the contralateral leg, when paired with hip extension, may facilitate a transition from stance to swing of the contralateral leg, resulting in an improvement in step length.…”

Section: Discussionmentioning

confidence: 99%

Motor Adaptation to Weight Shifting Assistance Transfers to Overground Walking in People with Spinal Cord Injury

Lin

Hsu

Dee

et al. 2019

PM&R

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Background Locomotor training has been used to improve walking function in people with incomplete spinal cord injury (iSCI), but functional gains are relatively small for some patients, which may be due to the lack of weight shifting training. Objective To determine whether applying a pelvis assistance force in the coronal plane during walking would improve weight shifting and stepping in people with iSCI. Design Repeated measures study. Setting Rehabilitation hospital. Participants Seventeen people with iSCI. Interventions A controlled assistance force was bilaterally applied to the pelvis in the medial‐lateral direction to facilitate weight shifting, which gradually increased during the course of treadmill walking. Main Outcome Measures Weight shifting, step length, margin of stability, and muscle activities of the weaker leg were used to quantify gait performance. The spatial‐temporal gait parameters during overground walking were collected pre, post, and 10 minutes after treadmill training. Results During treadmill walking, participants significantly improved weight shifting (ie, center of mass [CoM] lateral distance reduced from 0.16 ± 0.06 m to 0.12 ± 0.07 m, P = .012), and increased step length (from 0.35 ± 0.08 m to 0.37 ± 0.09 m, P = .037) on the stronger side when the force was applied, which were partially retained (ie, CoM distance was 0.14 ± 0.06, P = .019, and step length was 0.37 ± 0.09 m, P = .005) during the late postadaptation period when the force was removed. In addition, weight shifting and step length on the weaker side during overground walking also improved (support base reduced from 0.13 ± 0.06 m to 0.12 ± 0.06 m, P = .042, and step length increased from 0.48 ± 0.12 m to 0.51 ± 0.09 m, P = .045) after treadmill training. Conclusions Applying pelvis assistance during treadmill walking may facilitate weight shifting and improve step length in people with SCI, which may partially transfer to overground walking. Level of Evidence III.

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Spastic Reflexes Triggered by Ankle Load Release in Human Spinal Cord Injury

Abstract: . Spastic reflexes triggered by ankle load release in human spinal cord injury.

Cited by 17 publications

References 42 publications

Reflex responses to combined hip and knee motion in human chronic spinal cord injury

Reflex responses to combined hip and knee motion in human chronic spinal cord injury

Ankle Load Modulates Hip Kinetics and EMG During Human Locomotion

Motor Adaptation to Weight Shifting Assistance Transfers to Overground Walking in People with Spinal Cord Injury

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