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Neural Plasticity 2021This study presents single-fiber electromyography (EMG) analysis for assessment of paretic muscle changes after stroke. Single-fiber action potentials (SFAPs) were...
This study presents single-fiber electromyography (EMG) analysis for assessment of paretic muscle changes after stroke. Single-fiber action potentials (SFAPs) were recorded from the first dorsal interosseous (FDI) muscle bilaterally in 12 individuals with hemiparetic stroke. The SFAP parameters, including the negative peak duration and the peak-peak amplitude, were measured and further used to estimate muscle fiber diameter through a model based on the quadratic function. The SFAP parameters, fiber density, and muscle fiber diameter derived from the model were compared between the paretic and contralateral muscles. The results show that SFAPs recorded from the paretic muscle had significantly smaller negative peak duration than that from the contralateral muscle. As a result, the derived muscle fiber diameter of the paretic muscle was significantly smaller than that of the contralateral muscle. The fiber density of the paretic muscle was significantly higher than that of the contralateral muscle. These results provide further evidence of remodeled motor units after stroke and suggest that paretic muscle weakness can be due to both complex central and peripheral neuromuscular alterations.
Topics: Action Potentials; Aged; Electromyography; Female; Humans; Male; Middle Aged; Muscle Fibers, Skeletal; Muscle, Skeletal; Paresis; Stroke
PubMed: 34434227
DOI: 10.1155/2021/3045990 -
Critical Care (London, England) 2009Muscle weakness is highly prevalent during acute critical illness, with the poor exercise performance that occurs after critical illness being recognized as a...
Muscle weakness is highly prevalent during acute critical illness, with the poor exercise performance that occurs after critical illness being recognized as a consequence of skeletal muscles weakness. Advanced techniques to measure peripheral muscle strength are available, but they have limited use in the clinical setting. Simple volitional methods to assess strength are limited because they rely on patient motivation, which can be problematic in the critical care setting. At present, the mechanisms that underlie skeletal muscle wasting and weakness are poorly understood, but use of rehabilitation early in critical illness appears to have beneficial effects on outcome. The future direction will be to determine the underlying mechanisms as well as developing rehabilitation programmes during both the acute and the post critical illness stages.
Topics: Decision Making; Humans; Intensive Care Units; Muscle Weakness
PubMed: 19664190
DOI: 10.1186/cc7937 -
The Lancet. Neurology Mar 2018
Topics: Activities of Daily Living; Humans; Muscle Weakness; Myasthenia Gravis; Paresis
PubMed: 29452680
DOI: 10.1016/S1474-4422(18)30036-X -
Annual International Conference of the... Jul 2023Stroke is the leading cause of disability worldwide, and nearly 80% of stroke survivors suffer from upper-limb hemiparesis. Myoelectric exoskeletons can restore...
Stroke is the leading cause of disability worldwide, and nearly 80% of stroke survivors suffer from upper-limb hemiparesis. Myoelectric exoskeletons can restore dexterity and independence to stroke survivors with upper-limb hemiparesis. However, the ability of patients to dexterously control myoelectric exoskeletons is limited by an incomplete understanding of the electromyographic (EMG) hallmarks of hemiparesis, such as muscle weakness and spasticity. Here we show that stroke survivors with upper-limb hemiparesis suffer from delayed voluntary muscle contraction and delayed muscle relaxation. We quantified the time constants of EMG activity associated with initiating and terminating voluntary hand grasps and extensions for both the paretic and non-paretic hands of stroke survivors. We found that the initiation and termination time constants were greater on the paretic side for both hand grasps and hand extensions. Notably, the initiation time constant during hand extension was approximately three times longer for the paretic hand than for the contralateral non-paretic hand (0.618 vs 0.189 s). We also show a positive correlation between the initiation and termination time constants and clinical scores on the Modified Ashworth Scale. The difficulty stroke survivors have in efficiently modulating their EMG presents a challenge for appropriate control of assistive myoelectric devices, such as exoskeletons. This work constitutes an important step towards understanding EMG differences after stroke and how to accommodate these EMG differences in assistive myoelectric devices. Real-time quantitative biofeedback of EMG time constants may also have broad implications for guiding rehabilitation and monitoring patient recovery.Clinical Relevance- After a stroke, muscle activity changes, and these changes make it difficult to use muscle activity to drive assistive and rehabilitative technologies. We identified slower muscle contraction and muscle relaxation as a key difference in muscle activity after a stroke. This quantifiable difference in muscle activity can be used to develop better assistive technologies, guide rehabilitation, and monitor patient recovery.
Topics: Humans; Electromyography; Stroke; Upper Extremity; Paresis; Survivors; Muscles
PubMed: 38083023
DOI: 10.1109/EMBC40787.2023.10340726 -
Topics in Stroke Rehabilitation Dec 2016Muscle weakness is the most common impairment in the upper extremity after stroke, leading to a reduced ability to use the arm and the hand in daily activities. Grip...
BACKGROUND
Muscle weakness is the most common impairment in the upper extremity after stroke, leading to a reduced ability to use the arm and the hand in daily activities. Grip strength is easier to measure than precise, but more time-consuming, isokinetic and isometric arm muscle strength measurements. It would therefore be advantageous in a clinical setting if grip strength could be used as a proxy for muscle strength in the entire upper extremity.
OBJECTIVE
To investigate the association between grip strength and isometric and isokinetic arm muscle strength in persons with chronic stroke.
METHODS
Forty-five persons with mild-to-moderate paresis in the upper extremity, at least 6 months post-stroke participated. Isometric grip strength was measured with a computerized grip dynamometer and arm strength (isometric shoulder abduction and elbow flexion as well as isokinetic elbow extension and flexion) with an isokinetic dynamometer. Pearson's correlation coefficient was used to determine the association between the muscle strength measurements.
RESULTS
There were significant correlations (p < .0001) between grip strength and all arm strength measurements in both the more affected (r = 0.77-0.82) and the less affected upper extremity (r = 0.65-0.82).
CONCLUSION
This cross-sectional study showed that grip strength is strongly associated with muscle strength in the arm in persons in the chronic phase after stroke. As grip strength is easy to measure and less time-consuming than arm muscle strength measurements, this implies that grip strength can be a representative measure of muscle weakness of the entire upper extremity in the chronic phase after stroke.
Topics: Adult; Aged; Biomechanical Phenomena; Cross-Sectional Studies; Female; Hand Strength; Humans; Male; Middle Aged; Muscle Strength; Muscle Weakness; Paresis; Stroke; Upper Extremity
PubMed: 27145212
DOI: 10.1080/10749357.2016.1168591 -
European Geriatric Medicine Dec 2023We assessed the impact of applying different SARC-F cut-points for the identification of muscle weakness in an older clinical population.
PURPOSE
We assessed the impact of applying different SARC-F cut-points for the identification of muscle weakness in an older clinical population.
METHODS
We included 159 men and 311 women aged 56-98 years who had completed the SARC-F questionnaire and had their maximum grip strength measured at an Older People's Medicine Day Unit. We applied cut-points of ≥ 4, 3 and 2 to SARC-F and tested agreement with muscle weakness (grip strength < 27kg men, < 16kg women) in analyses stratified by sex and obesity status.
RESULTS
Prevalence of muscle weakness was 86.8% and 82.6% in men and women, respectively. Sensitivity of the SARC-F increased at lower cut-points (e.g. 81% for ≥ 4 vs 97% for ≥ 2 in women). There was typically greater sensitivity among women than men and among those classified as obese vs non-obese.
CONCLUSIONS
These findings suggest that different cut-points may be required to optimise the utility of SARC-F for identifying muscle weakness in different patient sub-groups.
Topics: Male; Humans; Female; Aged; Sarcopenia; Mass Screening; Cross-Sectional Studies; Hand Strength; Muscle Weakness; Paresis
PubMed: 37607997
DOI: 10.1007/s41999-023-00850-6 -
Journal of Neurology, Neurosurgery, and... Nov 1998According to the established clinical tradition about the distribution of weakness, the ratios of flexor/extensor strength of patients with upper motor neuron lesions...
According to the established clinical tradition about the distribution of weakness, the ratios of flexor/extensor strength of patients with upper motor neuron lesions are expected to be relatively high for the elbow and wrist and low for the knee. To assess the diagnostic value of these patterns of weakness, muscle strength of 70 patients with limb weakness of central or peripheral origin was measured with a hand held dynamometer. The ratios of flexor/extensor strength at the knee, elbow, and wrist did not differ significantly between patients with central or peripheral origin of muscle weakness. The examination of tendon jerks proved to be of more value as a localising feature. The traditional notion about the distribution of weakness in upper motor neuron lesions may be explained by an intrinsically greater strength in antigravity muscles, together with the effects of hypertonia.
Topics: Adult; Female; Humans; Male; Middle Aged; Motor Neuron Disease; Muscle Weakness
PubMed: 9810962
DOI: 10.1136/jnnp.65.5.794 -
Muscle & Nerve Feb 2024
Topics: Humans; Spine; Neurosurgical Procedures; Paresis; Atrophy; Muscle Weakness
PubMed: 38050793
DOI: 10.1002/mus.28007 -
PloS One 2023There is scarce evidence on changes at the functional level associated with the respiratory area in women. This study aims to analyse the relationship between... (Observational Study)
Observational Study
BACKGROUND
There is scarce evidence on changes at the functional level associated with the respiratory area in women. This study aims to analyse the relationship between inspiratory muscle strength and balance in women.
MATERIAL AND METHODS
In this cross-sectional observational study, the sample consisted of groups according to the results obtained in the balance test. Inspiratory muscle weakness was defined as maximum inspiratory pressure (MIP) ≤ 80% of the predictive value. MIP was carried out using through a mouthpiece, with an electronic manometer. Logistic regression model was used to examine if MIP predicts balance.
RESULTS
159 women participated in the study. Approximately 20% of them achieved balance ≤ 2 seconds and 18% presented MIP≤80%. MIP was associated with the time achieved in the one-leg support test. Subjects with MIP ≤ 80% of the predictive value show 3 times more risk of having a lower performance in the balance test (OR = 3.26).
CONCLUSIONS
Inspiratory muscle weakness is associated with deficient balance in this sample. It shows the need for multidimensional assessment and rehabilitation strategies for patients identified as having MIP weakness and/or balance disorders.
Topics: Humans; Female; Cross-Sectional Studies; Respiratory Muscles; Muscle Strength; Maximal Respiratory Pressures; Muscle Weakness; Paresis
PubMed: 36791078
DOI: 10.1371/journal.pone.0280465 -
Journal of Cardiopulmonary... 2011Reduced maximal, peripheral muscle strength is associated with exercise intolerance in patients with chronic obstructive pulmonary disease (COPD). Therefore, it is... (Review)
Review
PURPOSE
Reduced maximal, peripheral muscle strength is associated with exercise intolerance in patients with chronic obstructive pulmonary disease (COPD). Therefore, it is important to accurately evaluate muscle strength to identify patients with muscle weakness and to prescribe adequate loads for resistance training. The objective here was to systematically identify and summarize the literature on measurement of peripheral muscle strength in individuals with COPD and to make recommendations for strength testing in clinical and research settings.
METHODS
A literature search was conducted of electronic databases between 1999 and 2009 of all English language articles utilizing muscle strength measurements.
RESULTS
The search resulted in retrieval of 178 articles, of which 66 were reviewed. Isometric muscle strength was measured using handgrip (n = 30), strain gauge (n = 15), computerized dynamometer (n = 13), magnetic stimulation (n = 8), handheld dynamometer (n = 6), or manual testing (n = 3). Isotonic muscle strength was measured using a hydraulic system (n = 3) or 1-repetition maximum (n = 9), and isokinetic muscle strength was measured using computerized dynamometer (n = 16). Methodological issues such as limb position, number of trials, subject familiarization, test instructions, rest periods, and muscle group tested were all identified as important variables to consider when developing a strength-testing protocol.
CONCLUSION
Muscle strength has been measured in people with COPD using similar methods as in other clinical populations. Each method presents advantages and disadvantages that need to be considered when selecting the most relevant measure. Standardization of the test procedures is essential in both clinical and research settings to obtain valid and reliable measurements of muscle strength.
Topics: Exercise Tolerance; Humans; Muscle Strength; Muscle Strength Dynamometer; Muscle Weakness; Muscle, Skeletal; Pulmonary Disease, Chronic Obstructive; Reference Standards; Resistance Training; Weights and Measures
PubMed: 20724932
DOI: 10.1097/HCR.0b013e3181ebf302