Quantifying Altered Neural Connectivity of the Stretch Reflex in Chronic Hemiparetic Stroke

Yang, Yuan; Sinha, Nirvik; Tian, Runfeng; Gurari, Netta; Drogos, Justin M.; Dewald, Julius P. A.

doi:10.1109/tnsre.2020.2986304

Cited by 15 publications

(15 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At the beginning of the experiment, the participants were asked to lift the tested arm with their most effort to determine the maximum voluntary torque (MVT) of SABD. The average of three continuous trials without difference larger than 10% of the mean was considered as SABD MVT of the study participant [ 22 ]. Similarly, the EF MVT was determined when the arm was fully supported [ 22 ].…”

Section: Methodsmentioning

confidence: 99%

“…The average of three continuous trials without difference larger than 10% of the mean was considered as SABD MVT of the study participant [ 22 ]. Similarly, the EF MVT was determined when the arm was fully supported [ 22 ].…”

Section: Methodsmentioning

confidence: 99%

“…Participants performed 25 trials of each level task in total, with 5 trials of one level and shifted to 5 trials of another. The expression of the flexion synergy was quantified as the involuntary synergic elbow flexion torque generated during the SABD, and normalized to the EF MVT [ 22 ].…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Assessing the Usage of Indirect Motor Pathways Following a Hemiparetic Stroke

Tian

Dewald

Yang

2021

IEEE Trans. Neural Syst. Rehabil. Eng.

Self Cite

View full text Add to dashboard Cite

A hallmark impairment in a hemiparetic stroke is a loss of independent joint control resulting in abnormal coactivation of shoulder abductor and elbow flexor muscles in their paretic arm, clinically known as the flexion synergy. The flexion synergy appears while generating shoulder abduction (SABD) torques as lifting the paretic arm. This likely be caused by an increased reliance on contralesional indirect motor pathways following damage to direct corticospinal projections. The assessment of functional connectivity between brain and muscle signals, i.e., brain-muscle connectivity (BMC), may provide insight into such changes to the usage of motor pathways. Our previous model simulation shows that multi-synaptic connections along the indirect motor pathway can generate nonlinear connectivity. We hypothesize that increased usage of indirect motor pathways (as increasing SABD load) will lead to an increase of nonlinear BMC. To test this hypothesis, we measured brain activity, muscle activity from shoulder abductors when stroke participants generate 20% and 40% of maximum SABD torque with their paretic arm. We computed both linear and nonlinear BMC between EEG and EMG.We found dominant nonlinear BMC at contralesional/ipsilateral hemisphere for stroke, whose magnitude increased with the SABD load. These results supported our hypothesis and indicated that nonlinear BMC could provide a quantitative indicator for determining the usage of indirect motor pathways following a hemiparetic stroke.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Assessing the Usage of Indirect Motor Pathways Following a Hemiparetic Stroke

Tian

Dewald

Yang

2021

IEEE Trans. Neural Syst. Rehabil. Eng.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Increased involuntary muscle tone (i.e., hypertonia) makes limb movement difficult and is influenced by the need/demand/intention to use the paretic/nonparetic limb or the whole body [65][66][67]. Evidence further suggests that the same neural mechanism, upregulation of corticoreticulospinal system due to the lost corticofugal projections [68][69][70], underlies the manifestation of abnormal drive to paretic muscles in various forms, resulting in the expression of the flexion synergy [71][72][73], spasticity [74], associated reactions [75], paresis (resulting in 'learned non-use' [76]) and associated functional motor deficits. Thus, provided with the exact real-world context in which such deficits are experienced and manifested, the sEMG active duration can be a useful measure to probe into the true impact of abnormal neural drive and resulting motor impairments during activities of daily living.…”

Section: Robustness Against Simulated Noise Sourcesmentioning

confidence: 99%

A novel time-based surface EMG measure for quantifying hypertonia in paretic arm muscles during daily activities after hemiparetic stroke

Sohn

Deol

Dewald

2022

Preprint

View full text Add to dashboard Cite

After stroke, paretic arm muscles are constantly exposed to abnormal neural drive from the injured brain. As such, hypertonia, broadly defined as an increase in muscle tone, is prevalent especially in distal muscles, which impairs daily function or in long-term leads to a flexed resting posture in the wrist and fingers. However, there currently is no quantitative measure that can reliably track how hypertonia is expressed on daily basis. In this study, we propose a novel time-based surface electromyography (sEMG) measure that can overcome the limitations of the coarse clinical scales often measured in functionally irrelevant context and the magnitude-based sEMG measures that suffer from signal non-stationarity. We postulated that the key to robust quantification of hypertonia is to capture the true baseline in sEMG for each measurement session, by which we can define the relative duration of activity over a short time segment continuously tracked in a sliding window fashion. We validate that the proposed measure of sEMG active duration is robust across parameter choices (e.g., sampling rate, window length, threshold criteria), robust against typical noise sources present in paretic muscles (e.g., low signal-to-noise ratio, sporadic motor unit action potentials), and reliable across measurements (e.g., sensors, trials, and days), while providing a continuum of scale over the full magnitude range for each session. Furthermore, sEMG active duration could well characterize the clinically observed differences in hypertonia expressed across different muscles and impairment levels. The proposed measure can be used for continuous and quantitative monitoring of hypertonia during activities of daily living while at home, which will allow for the study of the practical effect of pharmacological and/or physical interventions that try to combat its presence.

show abstract

“…A recent study in hemiparetic stroke shows that the nonlinearity in the motor system increases due to an increased usage of multi-synaptic indirect motor pathways, e.g. cortico-reticulospinal tract [39], following damage to the mono-synaptic corticospinal tract [40].…”

Section: Nonlinearity In the Neuronal Level And Neural Systemsmentioning

confidence: 99%

Quantifying Altered Neural Connectivity of the Stretch Reflex in Chronic Hemiparetic Stroke

Cited by 15 publications

References 40 publications

Assessing the Usage of Indirect Motor Pathways Following a Hemiparetic Stroke

Assessing the Usage of Indirect Motor Pathways Following a Hemiparetic Stroke

A novel time-based surface EMG measure for quantifying hypertonia in paretic arm muscles during daily activities after hemiparetic stroke

Nonlinear System Identification of Neural Systems from Neurophysiological Signals

Contact Info

Product

Resources

About