Electrodiagnosis of Upper Limb Weakness in Acute Quadriplegia1

Little, James W.; Powers, Randall K.; Michelson, Paula; Moore, Donna L.; Robinson, Lawrence R.; Goldstein, Barry

doi:10.1097/00002060-199402000-00004

Cited by 23 publications

(5 citation statements)

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“…Some studies have demonstrated a relationship between spastic hypertonia and impaired function (Corcos et al, 1986, Eyre and Miller, 1993, Gottlieb and Myklebust, 1993), while other studies reject this relationship, based on clinical observations that reducing reflex hyperexcitability does not always promote functional improvement (Little et al, 1994, Norman et al, 1998). This discrepancy in the literature may be due to two major points (i) the hypothetical mechanism that stretch reflex hyperexcitability may not directly induce impaired function, but rather, may promote abnormal modulation of stretch reflexes during a voluntary movement (Dietz et al, 2002, Faist et al, 1996), and may also cause impairments (Eyre and Miller, 1993), and (ii) the debate regarding the origins of spasticity.…”

Section: Discussionmentioning

confidence: 99%

Effects of robotic-locomotor training on stretch reflex function and muscular properties in individuals with spinal cord injury

Mirbagheri

Kindig

Niu

2015

Clinical Neurophysiology

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Objective We sought to determine the therapeutic effect of robotic-assisted step training (RAST) on neuromuscular abnormalities associated with spasticity by characterization of their recovery patterns in people with spinal cord injury (SCI). Methods Twenty-three motor-incomplete SCI subjects received one-hour RAST sessions three times per week for four weeks, while an SCI control group received no training. Neuromuscular properties were assessed using ankle perturbations prior to and during the training, and a system-identification technique quantified stretch reflex and intrinsic stiffness magnitude and modulation with joint position. Growth-mixture modeling classified subjects based on similar intrinsic and reflex recovery patterns. Results All recovery classes in the RAST group presented significant (p<0.05) reductions in intrinsic and reflex stiffness magnitude and modulation with position; the control group presented no changes over time. Subjects with larger baseline abnormalities exhibited larger reductions, and over longer training periods. Conclusions Our findings demonstrate that RAST can effectively reduce neuromuscular abnormalities, with greater improvements for subjects with higher baseline abnormalities. Significance Our findings suggest, in addition to its primary goal of improving locomotor patterns, RAST can also reduce neuromuscular abnormalities associated with spasticity. These findings also demonstrate that these techniques can be used to characterize neuromuscular recovery patterns in response to various types of interventions.

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Section: Discussionmentioning

confidence: 99%

Effects of robotic-locomotor training on stretch reflex function and muscular properties in individuals with spinal cord injury

Mirbagheri

Kindig

Niu

2015

Clinical Neurophysiology

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“…Severe extensor spasticity of gastrocnemius, blocking flexion movements, can impede locomotor ability, and some studies have demonstrated that increased hypertonia relates to impaired function 3-5 . Others however, have demonstrated no functional improvements with reduced hypertonia, based on clinical observations 6,7 .…”

Section: Introductionmentioning

confidence: 99%

Interventions to Reduce Spasticity and Improve Function in People With Chronic Incomplete Spinal Cord Injury

Duffell

Brown

Mirbagheri

2014

Neurorehabil Neural Repair

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Background Spinal cord injury (SCI) results in impaired function and ankle joint spasticity is a common secondary complication. Different interventions have been trialed with variable results. Objective We investigated the effects of pharmacological and physical (locomotor training) interventions on function in people living with incomplete motor function loss due to SCI, and used different analytical techniques to understand whether functional levels affect recovery with different interventions. Methods Participants with an incomplete SCI were assigned to three groups; no intervention, Lokomat or tizanidine. Outcome measures were the 10-meter walk test (10MWT), 6-minute walk test (6MWT) and the Timed-up and go (TUG). Participants were classified in two ways; i) based on achieving an improvement above the minimally important difference (MID) and; ii) using Growth Mixture Modeling (GMM). Functional levels of participants that achieved the MID were compared and Random Coefficient Regression (RCR) was used to assess recovery in GMM classes. Results Overall, walking speed and endurance improved, with no difference between interventions. Only a small number of participants achieved the MID. Both MID and GMM-RCR analyses revealed that tizanidine improved endurance in high functioning participants. GMM-RCR classification also showed that speed and mobility improved after locomotor training. Conclusions Improvements in function were achieved in a limited number of people with SCI. Using the MID and GMM techniques, differences in responses to interventions between high and low functioning participants could be identified. These techniques may therefore have potential to be used for characterizing therapeutic effects due to different interventions.

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“…With a much simpler setup, the Brain Motor Control Assessment also informs the UMN integrity; in this approach, sEMG signals are recorded during voluntary movements and compared between individuals with UMN dysfunctions and a neurologically intact control group to determine the extent of UMN involvement [54,55]. To differentiate UMN and LMN damage, the M-wave in response to electrical stimulation is compared to the RMS during voluntary contraction, resulting in the M/RMS ratio, an indicator for UMN and LMN weaknesses [56]. Amplitude-based information extracted from sEMG recordings is crucial in the aforementioned assessments, but our results suggested that it can be complemented by additional feature types, as discussed below.…”

Section: Discussionmentioning

confidence: 99%

A computational model of surface electromyography signal alterations after spinal cord injury

Li,

Balbinot,

Furlan

et al. 2023

J. Neural Eng.

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Spinal cord injury (SCI) can cause significant impairment and disability with an impact on the quality of life for individuals with SCI and their caregivers. Surface electromyography (sEMG) is a sensitive and non-invasive technique to measure muscle activity and has demonstrated great potential in capturing neuromuscular changes resulting from SCI. The mechanisms of the sEMG signal characteristic changes due to SCI are multi-faceted and difficult to study in vivo. In this study, we utilized well-established computational models to characterize changes in sEMG signal after SCI and identify sEMG features that are sensitive and specific to different aspects of the SCI. Starting from existing models for motor neuron pool organization and motor unit action potential generation for healthy neuromuscular systems, we implemented scenarios to model damages to upper motor neurons, lower motor neurons, and the number of muscle fibers within each motor unit. After simulating sEMG signals from each scenario, we extracted time and frequency domain features and investigated the impact of SCI disruptions on sEMG features using the Kendall Rank Correlation analysis. The results indicate that commonly used amplitude-based sEMG features (such as mean absolute values and root mean square) cannot differentiate between injury scenarios, but a broader set of features (including autoregression and cepstrum coefficients) provides greater specificity to the type of damage present. We introduce a novel approach to mechanistically relate sEMG features (often underused in SCI research) to different types of neuromuscular alterations that may occur after SCI. This work contributes to the further understanding and utilization of sEMG in clinical applications, which will ultimately improve patient outcomes after SCI.

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Electrodiagnosis of Upper Limb Weakness in Acute Quadriplegia1

Cited by 23 publications

References 0 publications

Effects of robotic-locomotor training on stretch reflex function and muscular properties in individuals with spinal cord injury

Effects of robotic-locomotor training on stretch reflex function and muscular properties in individuals with spinal cord injury

Interventions to Reduce Spasticity and Improve Function in People With Chronic Incomplete Spinal Cord Injury

A computational model of surface electromyography signal alterations after spinal cord injury

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