scholarly journals Modular control of varied locomotor tasks in children with incomplete spinal cord injuries

2013 ◽  
Vol 110 (6) ◽  
pp. 1415-1425 ◽  
Author(s):  
Emily J. Fox ◽  
Nicole J. Tester ◽  
Steven A. Kautz ◽  
Dena R. Howland ◽  
David J. Clark ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Neural Control ◽  
Muscle Activation ◽  
Spinal Cord Injuries ◽  
Nonnegative Matrix ◽  
Treadmill Walking ◽  
Stair Climbing ◽  
Neurological Injury ◽  
Modular Control ◽  
Flexion Extension

A module is a functional unit of the nervous system that specifies functionally relevant patterns of muscle activation. In adults, four to five modules account for muscle activation during walking. Neurological injury alters modular control and is associated with walking impairments. The effect of neurological injury on modular control in children is unknown and may differ from adults due to their immature and developing nervous systems. We examined modular control of locomotor tasks in children with incomplete spinal cord injuries (ISCIs) and control children. Five controls (8.6 ± 2.7 yr of age) and five children with ISCIs (8.6 ± 3.7 yr of age performed treadmill walking, overground walking, pedaling, supine lower extremity flexion/extension, stair climbing, and crawling. Electromyograms (EMGs) were recorded in bilateral leg muscles. Nonnegative matrix factorization was applied, and the minimum number of modules required to achieve 90% of the “variance accounted for” (VAF) was calculated. On average, 3.5 modules explained muscle activation in the controls, whereas 2.4 modules were required in the children with ISCIs. To determine if control is similar across tasks, the module weightings identified from treadmill walking were used to reconstruct the EMGs from each of the other tasks. This resulted in VAF values exceeding 86% for each child and each locomotor task. Our results suggest that 1) modularity is constrained in children with ISCIs and 2) for each child, similar neural control mechanisms are used across locomotor tasks. These findings suggest that interventions that activate the neuromuscular system to enhance walking also may influence the control of other locomotor tasks.

scholarly journals Merging of Healthy Motor Modules Predicts Reduced Locomotor Performance and Muscle Coordination Complexity Post-Stroke

2010 ◽  
Vol 103 (2) ◽  
pp. 844-857 ◽  
Author(s):  
David J. Clark ◽  
Lena H. Ting ◽  
Felix E. Zajac ◽  
Richard R. Neptune ◽  
Steven A. Kautz
Keyword(s):  
Nervous System ◽  
Neural Control ◽  
Muscle Activation ◽  
Nonnegative Matrix ◽  
Modular Organization ◽  
Coordination Pattern ◽  
Muscle Coordination ◽  
Post Stroke ◽  
Muscle Activation Patterns ◽  
Flexion Extension

Evidence suggests that the nervous system controls motor tasks using a low-dimensional modular organization of muscle activation. However, it is not clear if such an organization applies to coordination of human walking, nor how nervous system injury may alter the organization of motor modules and their biomechanical outputs. We first tested the hypothesis that muscle activation patterns during walking are produced through the variable activation of a small set of motor modules. In 20 healthy control subjects, EMG signals from eight leg muscles were measured across a range of walking speeds. Four motor modules identified through nonnegative matrix factorization were sufficient to account for variability of muscle activation from step to step and across speeds. Next, consistent with the clinical notion of abnormal limb flexion-extension synergies post-stroke, we tested the hypothesis that subjects with post-stroke hemiparesis would have altered motor modules, leading to impaired walking performance. In post-stroke subjects ( n = 55), a less complex coordination pattern was shown. Fewer modules were needed to account for muscle activation during walking at preferred speed compared with controls. Fewer modules resulted from merging of the modules observed in healthy controls, suggesting reduced independence of neural control signals. The number of modules was correlated to preferred walking speed, speed modulation, step length asymmetry, and propulsive asymmetry. Our results suggest a common modular organization of muscle coordination underlying walking in both healthy and post-stroke subjects. Identification of motor modules may lead to new insight into impaired locomotor coordination and the underlying neural systems.

Epidemiology of Spinal Cord Injuries and Their Outcomes: A Study at King Khalid Hospital (KKH), Najran, Saudi Arabia, June 2018–June 2019

2021 ◽  
pp. 30
Author(s):  
Ahood Mahjari
Keyword(s):  
Spinal Cord ◽  
Saudi Arabia ◽  
Traffic Accident ◽  
Spinal Cord Injuries ◽  
Road Traffic ◽  
Neurological Injury ◽  
National Data ◽  
Common Cause ◽  
Younger Age ◽  
Cord Injury

Introduction: Spinal cord injury (SCI) is a life-changing neurological injury that puts a significant load on the healthcare system. SCI can be caused by several reasons such as road traffic accident (RTA), motor traffic accident (MTA), fall, gunshots, or bomb blast. There is not much national data concerning the etiology of SCI in Saudi Arabia. Therefore, we conducted this study to quantify the number of SCI incidence at King Khalid Hospital (KKH), Najran between June 2018 and June 2019. The study aimed at reviewing the rate and epidemiology of SCI at KKH for all patients admitted to the hospital during the study period and examining the causes of SCI for suggesting prevention strategies. Methodology: This retrospective study included all patients with SCI admitted to KKH during the mentioned period. Several factors for each patient were recorded including their age, gender, nationality, cause of SCI, and the outcomes of neurological injury. Result: In total, 182 SCI patients were admitted during the study period: 53% of them were male, and those aged 16–30 years were most vulnerable to SCI. RTA was the most common cause of SCI for males (59%), followed by bomb blasts (15%). While fall was ranked as the second cause of SCI in males (15.4%), it was the main reason for SCI in females 13%, followed by RTA. The majority of admitted cases in younger age was stable and improved, however, after RTA four patients had quadriplegia and six cases had paraplegia. Conclusion: RTA is the most common cause of SCI followed by fall and bomb blast. Younger patients are more likely to improve after SCI compared to elderly patients.

Neuromuscular efficiency of men with high and low spinal cord injury levels compared with non-disabled participants

2020 ◽  
pp. 1-10
Author(s):  
Frederico Ribeiro Neto ◽  
Rodrigo Rodrigues Gomes Costa ◽  
Ricardo Antônio Tanhoffer ◽  
Josevan Cerqueira Leal ◽  
Martim Bottaro ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Latissimus Dorsi ◽  
Muscle Activation ◽  
Assessment Tool ◽  
Shoulder Abduction ◽  
Trunk Flexion ◽  
Flexion Extension ◽  
Cord Injury ◽  
Trunk Extension

BACKGROUND: The neuromuscular efficiency index (NME) is defined as the individual ability to generate force in relation to the muscle activation level and might be useful to the assessment of individuals with spinal cord injury (SCI) and might elucidate the modifications in strength after an SCI compared to non-disabled subjects (CG). OBJECTIVE: Verify if the NME of fully and partially preserved muscles discriminate men with low and high levels of SCI and a matched non-disabled CG. METHODS: Fifty-four men with SCI were stratified into the high (HP), and low (LP) paraplegia groups and twenty-seven non-disabled individuals were selected (CG). All subjects performed maximum strength tests in the isokinetic dynamometer for shoulder abduction/adduction (isokinetic) and trunk flexion/extension (isometric). Surface electromyography was measured to calculate the NME, and discriminant analysis was carried out to identify which NME variables would be able to discriminate HP, LP, and CG. RESULTS: There were no NME significant differences between groups for the primary muscles of the shoulder abduction/adduction. All NME data failed at discriminant tolerance test to compare HP from LP. The latissimus dorsi NME during trunk extension discriminated CG from HP and LP. CONCLUSIONS: The latissimus dorsi NME during trunk extension might be used as an assessment tool to compare SCI individuals and the non-disabled-matched controls. The authors recommend using the NME index for the analysis or comparisons between the same SCI levels.

The Human Central Pattern Generator for Locomotion: Does It Exist and Contribute to Walking?

2017 ◽  
Vol 23 (6) ◽  
pp. 649-663 ◽  
Author(s):  
Karen Minassian ◽  
Ursula S. Hofstoetter ◽  
Florin Dzeladini ◽  
Pierre A. Guertin ◽  
Auke Ijspeert
Keyword(s):  
Spinal Cord ◽  
Neural Control ◽  
Muscle Activation ◽  
Central Pattern Generators ◽  
Lumbar Spinal Cord ◽  
Step Cycle ◽  
Experimental Conditions ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Cord Injury

The ability of dedicated spinal circuits, referred to as central pattern generators (CPGs), to produce the basic rhythm and neural activation patterns underlying locomotion can be demonstrated under specific experimental conditions in reduced animal preparations. The existence of CPGs in humans is a matter of debate. Equally elusive is the contribution of CPGs to normal bipedal locomotion. To address these points, we focus on human studies that utilized spinal cord stimulation or pharmacological neuromodulation to generate rhythmic activity in individuals with spinal cord injury, and on neuromechanical modeling of human locomotion. In the absence of volitional motor control and step-specific sensory feedback, the human lumbar spinal cord can produce rhythmic muscle activation patterns that closely resemble CPG-induced neural activity of the isolated animal spinal cord. In this sense, CPGs in humans can be defined by the activity they produce. During normal locomotion, CPGs could contribute to the activation patterns during specific phases of the step cycle and simplify supraspinal control of step cycle frequency as a feedforward component to achieve a targeted speed. Determining how the human CPGs operate will be essential to advance the theory of neural control of locomotion and develop new locomotor neurorehabilitation paradigms.

Pediatric spinal injury: the very young

1988 ◽  
Vol 68 (1) ◽  
pp. 25-30 ◽  
Author(s):  
John R. Ruge ◽  
Grant P. Sinson ◽  
David G. McLone ◽  
Leonard J. Cerullo
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Spinal Cord Injuries ◽  
Spinal Injury ◽  
Causative Factor ◽  
Important Variable ◽  
Neurological Injury ◽  
Content Type ◽  
Significant Difference ◽  
Cord Injury

✓ Maturity of the spine and spine-supporting structures is an important variable distinguishing spinal cord injuries in children from those in adults. Cinical data are presented from 71 children aged 12 years or younger who constituted 2.7% of 2598 spinal cord-injured patients admitted to the authors' institutions from June, 1972, to June, 1986. The 47 children with traumatic spinal cord injury averaged 6.9 years of age and included 20 girls (43%). The etiology of the pediatric injuries differed from that of adult injuries in that falls were the most common causative factor (38%) followed by automobile-related injuries (20%). Ten children (21.3%) had spinal cord injury without radiographic abnormality (SCIWORA), whereas 27 (57%) had evidence of neurological injury. Complete neurological injury was seen in 19% of all traumatic pediatric spinal cord injuries and in 40% of those with SCIWORA. The most frequent level of spinal injury was C-2 (27%, 15 cases) followed by T-10 (13%, seven cases). Upon statistical examination of the data, a subpopulation of children aged 3 years or younger emerged. These very young children had a significant difference in level of injury, requirement for surgical stability, and sex distribution compared to 4- to 12-year-old children.

Neuromuscular Adaptation During Skill Acquisition on a Two Degree-of-Freedom Target-Acquisition Task: Isometric Torque Production

2005 ◽  
Vol 94 (5) ◽  
pp. 3046-3057 ◽  
Author(s):  
Jonathan Shemmell ◽  
Matthew Forner ◽  
James R. Tresilian ◽  
Stephan Riek ◽  
Benjamin K. Barry ◽  
...  
Keyword(s):  
Skill Acquisition ◽  
Neural Control ◽  
Muscle Activation ◽  
Joint Torque ◽  
Acquisition Time ◽  
Neutral Position ◽  
Target Acquisition ◽  
Joint Torques ◽  
Flexion Extension ◽  
Torque Development

In this study we attempted to identify the principles that govern the changes in neural control that occur during repeated performance of a multiarticular coordination task. Eight participants produced isometric flexion/extension and pronation/supination torques at the radiohumeral joint, either in isolation (e.g., flexion) or in combination (e.g., flexion–supination), to acquire targets presented by a visual display. A cursor superimposed on the display provided feedback of the applied torques. During pre- and postpractice tests, the participants acquired targets in eight directions located either 3.6 cm (20% maximal voluntary contraction [MVC]) or 7.2 cm (40% MVC) from a neutral cursor position. On each of five consecutive days of practice the participants acquired targets located 5.4 cm (30% MVC) from the neutral position. EMG was recorded from eight muscles contributing to torque production about the radiohumeral joint during the pre- and posttests. Target-acquisition time decreased significantly with practice in most target directions and at both target torque levels. These performance improvements were primarily associated with increases in the peak rate of torque development after practice. At a muscular level, these changes were brought about by increases in the rates of recruitment of all agonist muscles. The spatiotemporal organization of muscle synergies was not significantly altered after practice. The observed adaptations appear to lead to performances that are generalizable to actions that require both greater and smaller joint torques than that practiced, and may be successfully recalled after a substantial period without practice. These results suggest that tasks in which performance is improved by increasing the rate of muscle activation, and thus the rate of joint torque development, may benefit in terms of the extent to which acquired levels of performance are maintained over time.

Mortality rates in geriatric patients with spinal cord injuries

2007 ◽  
Vol 7 (3) ◽  
pp. 277-281 ◽  
Author(s):  
Daniel R. Fassett ◽  
James S. Harrop ◽  
Mitchell Maltenfort ◽  
Shiveindra B. Jeyamohan ◽  
John D. Ratliff ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Mortality Rate ◽  
Geriatric Patients ◽  
Spinal Cord Injuries ◽  
Mortality Rates ◽  
Neurological Injury ◽  
Patient Age ◽  
Younger Patients ◽  
Patient Âgé ◽  
Chi Square Analysis

Object The authors undertook this study to evaluate the incidence of spinal cord injury (SCI) in geriatric patients (≥ 70 years of age) and examine the impact of patient age, extent of neurological injury, and spinal level of injury on the mortality rate associated with traumatic SCI. Methods A prospectively maintained SCI database (3481 patients) at a single institution was retrospectively studied for the period from 1978 through 2005. Parameters analyzed included patient age, admission American Spinal Injury Association (ASIA) motor score, level of SCI, mechanism of injury, and mortality data. The data pertaining to the 412 patients 70 years of age and older were compared with those pertaining to the younger cohort using a chi-square analysis. Results Since 1980, the number of SCI-related hospital admissions per year have increased fivefold in geriatric patients and the percentage of geriatric patients within the SCI population has increased from 4.2 to 15.4%. In comparison with younger patients, geriatric patients were found to be less likely to have severe neurological deficits (greater percentage of ASIA Grades C and D injuries), but the mortality rates were higher in the older age group both for the period of hospitalization (27.7% compared with 3.2%, p < 0.001) and during 1-year follow-up. The mortality rates in this older population directly correlate with the severity of neurological injury (1-year mortality rate, ASIA Grade A 66%, Grade D 23%, p < 0.001). The mortality rate in elderly patients with SCI has not changed significantly over the last two decades, and the 1-year mortality rate was greater than 40% in all periods analyzed. Conclusions Spinal cord injuries in older patients are becoming more prevalent. The mortality rate in this patient group is much greater than in younger patients and should be taken into account when aggressive interventions are considered and in counseling families regarding prognosis.

scholarly journals Spinal Cord Injuries – When Is the Initial Tomography Insufficient?

2017 ◽  
Vol 39 (04) ◽  
pp. 294-299
Author(s):  
Pedro Augusto Sousa Rodrigues ◽  
Enrico Ghizoni ◽  
Helder Tedeschi ◽  
Andrei Fernandes Joaquim
Keyword(s):  
Computed Tomography ◽  
Spinal Cord ◽  
Spinal Cord Injuries ◽  
Comprehensive Evaluation ◽  
Neurological Injury ◽  
Mri Findings ◽  
Clinical Scenarios ◽  
Cord Injury ◽  
Polytrauma Patients ◽  
Magnetic Resonance Imaging Mri

Abstract Introduction Spinal cord injury (SCI) is common in polytrauma patients. The standard exam for the initial evaluation is computed tomography (CT), due to its higher sensitivity and specificity when compared with plain radiographs. However, CT is insufficient for the management of some cases, especially to evaluate ligamentous and spinal cord injuries. The objective of the present study is to describe clinical scenarios in which the CT scan was insufficient to guide the treatment of SCIs. Methods We present the cases of four polytrauma patients with normal CT scans at admission and with unstable or surgically-treated lesions. Discussion The cases reported evidence the need for ongoing neurological surveillance with serial physical examination and magnetic resonance imaging (MRI) in cases of neurological injury not explained by CT or occult instability. Conclusion Computed tomography is not always sufficient to determine the management of SCIs. A comprehensive evaluation of the clinical data, CT findings and, occasionally, MRI findings is crucial in order to choose the best conduct.

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