@article{ef45dec7127e4a2bb8ec214ad7a154f3,
title = "Deficits in corticospinal control of stretch reflex thresholds in stroke: Implications for motor impairment",
abstract = "Objectives: The corticospinal system (CS) regulates muscle activation through shifts in muscle-level tonic stretch-reflex thresholds (TSRT). This ability is impaired in stroke and contributes to sensorimotor impairments such as spasticity. We determined the role of CS in elbow flexor activity regulation in healthy and post-stroke subjects. We also determined whether CS modulation deficits were related to sensorimotor impairment intensity in post-stroke individuals. Methods: Seventeen healthy (59.8 ± 12.2 yr) and 27 stroke subjects (58.7 ± 10.1 yr) had transcranial magnetic stimulation (TMS) applied over the primary motor cortex (M1) flexor representation to elicit motor-evoked potentials (MEPs) in elbow flexors in different angular positions. In a subset of post-stroke subjects (n = 12), flexor TSRTs were measured in passive and active conditions, and TSRT modulation was determined. Results: Position-related MEP amplitude modulation was similar in healthy and mild stroke subjects, while subjects with more severe stroke exhibited less consistent modulation. MEP modulation in stroke was related to clinical upper limb motor impairment, spasticity, and the ability to modulate TSRTs between passive and active elbow movements. Conclusions: CS output was closely related to TSRT modulation. Impairments in TSRT regulation may underlie motor deficits in moderate-to-severe post-stroke individuals. Significance: Translation of these neurophysiological findings to clinical applications may enhance post-stroke motor recovery.",
keywords = "Corticospinal tract, Motor control, Spasticity, Stretch-reflex threshold, Stroke",
author = "Daniele Piscitelli and Turpin, {Nicolas A.} and Subramanian, {Sandeep K.} and Feldman, {Anatol G.} and Levin, {Mindy F.}",
note = "Funding Information: This work was supported by the National Science and Engineering Research Council and Heart and Stroke Foundation of Canada-CPSR , MFL held a Canada Research Chair in Motor Recovery and Rehabilitation. DP was supported by the Fonds de la Recherche du Qu{\'e}bec en Sant{\'e} (FRQS). NAT was supported by program Mentor (REPAR/FRSC). SKS was supported by a Focus on Stroke Post-Doctoral Fellowship awarded by the Heart and stroke Foundation of Canada. The authors are very much grateful to Dr. Monica A Perez for her valuable comments and suggestions. We also acknowledge Rhona Guberek,Vira Rose, Cynthia Siino and Aaron Feldman for their help with clinical evaluation, patient recruitment and data analysis respectively. Funding Information: This work was supported by the National Science and Engineering Research Council and Heart and Stroke Foundation of Canada-CPSR, MFL held a Canada Research Chair in Motor Recovery and Rehabilitation. DP was supported by the Fonds de la Recherche du Que?bec en Sante? (FRQS). NAT was supported by program Mentor (REPAR/FRSC). SKS was supported by a Focus on Stroke Post-Doctoral Fellowship awarded by the Heart and stroke Foundation of Canada. The authors are very much grateful to Dr. Monica A Perez for her valuable comments and suggestions. We also acknowledge Rhona Guberek,Vira Rose, Cynthia Siino and Aaron Feldman for their help with clinical evaluation, patient recruitment and data analysis respectively. Publisher Copyright: {\textcopyright} 2020 International Federation of Clinical Neurophysiology",
year = "2020",
month = sep,
doi = "10.1016/j.clinph.2020.05.030",
language = "English (US)",
volume = "131",
pages = "2067--2078",
journal = "Electroencephalography and Clinical Neurophysiology - Electromyography and Motor Control",
issn = "1388-2457",
publisher = "Elsevier Ireland Ltd",
number = "9",
}