Sina Sangari1, Henrik Lundell2, Steven Kirshblum3, Monica A Perez1. 1. Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami and Bruce W. Carter Department of Veterans Affairs Medical Center, Miami, FL. 2. Danish Research Center for Magnetic Resonance, Center for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark. 3. Kessler Institute for Rehabilitation, Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Newark, NJ.
Abstract
OBJECTIVE: Spasticity is one of the most common symptoms manifested in humans with spinal cord injury (SCI). The neural mechanisms contributing to its development are not yet understood. Using neurophysiological and imaging techniques, we examined the influence of residual descending motor pathways on spasticity in humans with SCI. METHODS: We measured spasticity in 33 individuals with motor complete SCI (determined by clinical examination) without preservation of voluntary motor output in the quadriceps femoris muscle. To examine residual descending motor pathways, we used magnetic and electrical stimulation over the leg motor cortex to elicit motor evoked potentials (MEPs) in the quadriceps femoris muscle and structural magnetic resonance imaging to measure spinal cord atrophy. RESULTS: We found that 60% of participants showed symptoms of spasticity, whereas the other 40% showed no spasticity, demonstrating the presence of 2 clear subgroups of humans with motor complete SCI. MEPs were only present in individuals who had spasticity, and MEP size correlated with the severity of spasticity. Spinal cord atrophy was greater in nonspastic compared with spastic subjects. Notably, the degree of spared tissue in the lateral regions of the spinal cord was positively correlated with the severity of spasticity, indicating preservation of white matter related to motor tracts when spasticity was present. INTERPRETATION: These results support the hypothesis that preservation of descending motor pathways influences spasticity in humans with motor complete SCI; this knowledge might help the rehabilitation and assessment of people with SCI. ANN NEUROL 2019.
OBJECTIVE:Spasticity is one of the most common symptoms manifested in humans with spinal cord injury (SCI). The neural mechanisms contributing to its development are not yet understood. Using neurophysiological and imaging techniques, we examined the influence of residual descending motor pathways on spasticity in humans with SCI. METHODS: We measured spasticity in 33 individuals with motor complete SCI (determined by clinical examination) without preservation of voluntary motor output in the quadriceps femoris muscle. To examine residual descending motor pathways, we used magnetic and electrical stimulation over the leg motor cortex to elicit motor evoked potentials (MEPs) in the quadriceps femoris muscle and structural magnetic resonance imaging to measure spinal cord atrophy. RESULTS: We found that 60% of participants showed symptoms of spasticity, whereas the other 40% showed no spasticity, demonstrating the presence of 2 clear subgroups of humans with motor complete SCI. MEPs were only present in individuals who had spasticity, and MEP size correlated with the severity of spasticity. Spinal cord atrophy was greater in nonspastic compared with spastic subjects. Notably, the degree of spared tissue in the lateral regions of the spinal cord was positively correlated with the severity of spasticity, indicating preservation of white matter related to motor tracts when spasticity was present. INTERPRETATION: These results support the hypothesis that preservation of descending motor pathways influences spasticity in humans with motor complete SCI; this knowledge might help the rehabilitation and assessment of people with SCI. ANN NEUROL 2019.
Authors: Radoje D Čobeljić; Ksenija Ribarič-Jankes; Antonina Aleksić; Lana Z Popović-Maneski; Laszlo B Schwirtlich; Dejan B Popović Journal: Int J Rehabil Res Date: 2018-09 Impact factor: 1.479
Authors: Isabela Peña Pino; Caleb Hoover; Shivani Venkatesh; Aliya Ahmadi; Dylan Sturtevant; Nick Patrick; David Freeman; Ann Parr; Uzma Samadani; David Balser; Andrei Krassioukov; Aaron Phillips; Theoden I Netoff; David Darrow Journal: Front Syst Neurosci Date: 2020-06-30