scholarly journals 2282 Targeted eccentric motor control to improve locomotion after incomplete spinal cord injury

2018 ◽  
Vol 2 (S1) ◽  
pp. 29-29
Author(s):  
Kevin O’Brien ◽  
D. Michele Basso ◽  
James Schmiedeler
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Muscle Activation ◽  
Muscle Power ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
Motor Deficits ◽  
Incomplete Spinal Cord Injury ◽  
Cord Injury ◽  
Weight Acceptance

OBJECTIVES/SPECIFIC AIMS: Incomplete spinal cord injury typically results in life-long disability, often in the form of profound loss of locomotion capability. Individuals who have experienced incomplete spinal cord injury exhibit persistent eccentric motor deficits, which are particularly prevalent in the weight acceptance phase of gait and emphasized in sagittal plane knee motion and frontal plane hip motion. METHODS/STUDY POPULATION: Motion analysis can capture the kinematic and joint-level deficits of these individuals, but it is impossible to directly calculate the contributions of individual muscles to weight acceptance due to the complexity of the musculoskeletal system. Instead, those muscle contributions must be simulated in order to approximate muscle power during locomotion. RESULTS/ANTICIPATED RESULTS: The traditional method for driving these simulations with electromyography readings is unavailable for individuals who have neuromuscular deficits (e.g., spasticity or paralysis), due to the need to generate reliable maximum voluntary isometric contractions for baseline purposes. Instead, this research develops a novel method for using resting electromyography data to drive musculoskeletal simulations using a muscle activation threshold paradigm. DISCUSSION/SIGNIFICANCE OF IMPACT: The simulation results of this method more closely resemble experimental results, but further simulation refinement is needed to fully capture the true muscle activity.

scholarly journals Speed impacts frontal-plane maneuver stability of individuals with incomplete spinal cord injury

2020 ◽  
Vol 71 ◽  
pp. 107-114
Author(s):  
Carolina Viramontes ◽  
Mengnan/Mary Wu ◽  
Julian Acasio ◽  
Janis Kim ◽  
Keith E. Gordon
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Frontal Plane ◽  
Incomplete Spinal Cord Injury ◽  
Cord Injury

scholarly journals Changes in Locomotor Muscle Activity After Treadmill Training in Subjects With Incomplete Spinal Cord Injury

2009 ◽  
Vol 101 (2) ◽  
pp. 969-979 ◽  
Author(s):  
Monica A. Gorassini ◽  
Jonathan A. Norton ◽  
Jennifer Nevett-Duchcherer ◽  
Francois D. Roy ◽  
Jaynie F. Yang
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Treadmill Training ◽  
Emg Activity ◽  
Incomplete Spinal Cord Injury ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Cord Injury

Intensive treadmill training after incomplete spinal cord injury can improve functional walking abilities. To determine the changes in muscle activation patterns that are associated with improvements in walking, we measured the electromyography (EMG) of leg muscles in 17 individuals with incomplete spinal cord injury during similar walking conditions both before and after training. Specific differences were observed between subjects that eventually gained functional improvements in overground walking (responders), compared with subjects where treadmill training was ineffective (nonresponders). Although both groups developed a more regular and less clonic EMG pattern on the treadmill, it was only the tibialis anterior and hamstring muscles in the responders that displayed increases in EMG activation. Likewise, only the responders demonstrated decreases in burst duration and cocontraction of proximal (hamstrings and quadriceps) muscle activity. Surprisingly, the proximal muscle activity in the responders, unlike nonresponders, was three- to fourfold greater than that in uninjured control subjects walking at similar speeds and level of body weight support, suggesting that the ability to modify muscle activation patterns after injury may predict the ability of subjects to further compensate in response to motor training. In summary, increases in the amount and decreases in the duration of EMG activity of specific muscles are associated with functional recovery of walking skills after treadmill training in subjects that are able to modify muscle activity patterns following incomplete spinal cord injury.

scholarly journals Strategies to augment volitional and reflex function may improve locomotor capacity following incomplete spinal cord injury

2018 ◽  
Vol 119 (3) ◽  
pp. 894-903
Author(s):  
Kristan A. Leech ◽  
Hyosub E. Kim ◽  
T. George Hornby
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Muscle Activation ◽  
Afferent Input ◽  
Incomplete Spinal Cord Injury ◽  
Locomotor Function ◽  
Cord Injury ◽  
Neurophysiological Mechanisms ◽  
Locomotor Capacity ◽  
Spinal Excitability

Many studies highlight the remarkable plasticity demonstrated by spinal circuits following an incomplete spinal cord injury (SCI). Such plasticity can contribute to improvements in volitional motor recovery, such as walking function, although similar mechanisms underlying this recovery may also contribute to the manifestation of exaggerated responses to afferent input, or spastic behaviors. Rehabilitation interventions directed toward augmenting spinal excitability have shown some initial success in improving locomotor function. However, the potential effects of these strategies on involuntary motor behaviors may be of concern. In this article, we provide a brief review of the mechanisms underlying recovery of volitional function and exaggerated reflexes, and the potential overlap between these changes. We then highlight findings from studies that explore changes in spinal excitability during volitional movement in controlled conditions, as well as altered kinematic and behavioral performance during functional tasks. The initial focus will be directed toward recovery of reflex and volitional behaviors following incomplete SCI, followed by recent work elucidating neurophysiological mechanisms underlying patterns of static and dynamic muscle activation following chronic incomplete SCI during primarily single-joint movements. We will then transition to studies of locomotor function and the role of altered spinal integration following incomplete SCI, including enhanced excitability of specific spinal circuits with physical and pharmacological interventions that can modulate locomotor output. The effects of previous and newly developed strategies will need to focus on changes in both volitional function and involuntary spastic reflexes for the successful translation of effective therapies to the clinical setting.

scholarly journals Stepping responses to treadmill perturbations vary with severity of motor deficits in human SCI

2018 ◽  
Vol 120 (2) ◽  
pp. 497-508
Author(s):  
Virginia W. T. Chu ◽  
T. George Hornby ◽  
Brian D. Schmit
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Sagittal Plane ◽  
Heel Strike ◽  
Motor Deficits ◽  
Sensory Drive ◽  
Walking Control ◽  
Novel Approach ◽  
Cord Injury ◽  
Healthy Participants

In this study, we investigated the responses to tread perturbations during human stepping on a treadmill. Our approach was to test the effects of perturbations to a single leg using a split-belt treadmill in healthy participants and in participants with varying severity of spinal cord injury (SCI). We recruited 11 people with incomplete SCI and 5 noninjured participants. As participants walked on an instrumented treadmill, the belt on one side was stopped or accelerated briefly during midstance to late stance. A majority of participants initiated an unnecessary swing when the treadmill was stopped in midstance, although the likelihood of initiating a step was decreased in participants with more severe SCI. Accelerating or decelerating one belt of the treadmill during stance altered the characteristics of swing. We observed delayed swing initiation when the belt was decelerated (i.e., the hip was in a more flexed position at time of swing) and advanced swing initiation with acceleration (i.e., hip extended at swing initiation). Furthermore, the timing and leg posture of heel strike appeared to remain constant, reflected by a sagittal plane hip angle at heel strike that remained the same regardless of the perturbation. In summary, our results supported the current understanding of the role of sensory feedback and central drive in the control of stepping in participants with incomplete SCI and noninjured participants. In particular, the observation of unnecessary swing during a stop perturbation highlights the interdependence of central and sensory drive in walking control. NEW & NOTEWORTHY Using a novel approach with a split-belt treadmill, we tested the effects of hip angle perturbations to a single leg in healthy participants and participants with varying severity of spinal cord injury (SCI). A majority of participants initiated an unnecessary swing when the treadmill was stopped in midstance, although the likelihood of initiating a step decreased with the severity of SCI. Our results demonstrated interdependence of central and sensory drive in walking control.

scholarly journals Kinematic, Muscular, and Metabolic Responses During Exoskeletal-, Elliptical-, or Therapist-Assisted Stepping in People With Incomplete Spinal Cord Injury

2012 ◽  
Vol 92 (10) ◽  
pp. 1278-1291 ◽  
Author(s):  
T. George Hornby ◽  
Catherine R. Kinnaird ◽  
Carey L. Holleran ◽  
Miriam R. Rafferty ◽  
Kelly S. Rodriguez ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Oxygen Consumption ◽  
Sagittal Plane ◽  
Metabolic Responses ◽  
Control Individual ◽  
Emg Activity ◽  
Locomotor Training ◽  
Incomplete Spinal Cord Injury ◽  
Cord Injury

BackgroundRobotic-assisted locomotor training has demonstrated some efficacy in individuals with neurological injury and is slowly gaining clinical acceptance. Both exoskeletal devices, which control individual joint movements, and elliptical devices, which control endpoint trajectories, have been utilized with specific patient populations and are available commercially. No studies have directly compared training efficacy or patient performance during stepping between devices.ObjectiveThe purpose of this study was to evaluate kinematic, electromyographic (EMG), and metabolic responses during elliptical- and exoskeletal-assisted stepping in individuals with incomplete spinal cord injury (SCI) compared with therapist-assisted stepping.DesignA prospective, cross-sectional, repeated-measures design was used.MethodsParticipants with incomplete SCI (n=11) performed 3 separate bouts of exoskeletal-, elliptical-, or therapist-assisted stepping. Unilateral hip and knee sagittal-plane kinematics, lower-limb EMG recordings, and oxygen consumption were compared across stepping conditions and with control participants (n=10) during treadmill stepping.ResultsExoskeletal stepping kinematics closely approximated normal gait patterns, whereas significantly greater hip and knee flexion postures were observed during elliptical-assisted stepping. Measures of kinematic variability indicated consistent patterns in control participants and during exoskeletal-assisted stepping, whereas therapist- and elliptical-assisted stepping kinematics were more variable. Despite specific differences, EMG patterns generally were similar across stepping conditions in the participants with SCI. In contrast, oxygen consumption was consistently greater during therapist-assisted stepping.LimitationsLimitations included a small sample size, lack of ability to evaluate kinetics during stepping, unilateral EMG recordings, and sagittal-plane kinematics.ConclusionsDespite specific differences in kinematics and EMG activity, metabolic activity was similar during stepping in each robotic device. Understanding potential differences and similarities in stepping performance with robotic assistance may be important in delivery of repeated locomotor training using robotic or therapist assistance and for consumers of robotic devices.

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