RT Journal Article
SR Electronic
T1 Altered excitability of motor neuron pathways after stroke: more than upper motor neuron impairments
JF Stroke and Vascular Neurology
JO Stroke Vasc Neurol
FD BMJ Publishing Group Ltd
SP svn-2022-001568
DO 10.1136/svn-2022-001568
A1 Li, Pingping
A1 Chen, Chunyong
A1 Huang, Baozi
A1 Jiang, Zimu
A1 Wei, Jiating
A1 Zeng, Jinsheng
YR 2022
UL http://svn.bmj.com/content/early/2022/06/30/svn-2022-001568.abstract
AB Background Previous studies have suggested that impairment occurs in the lower motor neuron (LMN) pathway after stroke, but more research remains to be supported.Objective In this study, we tested the hypotheses: (1) both motor cortex and peripheral nerve pathways have decreased excitability and structural damage after stroke; (2) parameters of transcranial magnetic stimulation motor evoked potentials (TMS-MEP) can be used as predictors of motor function and stroke prognosis.Methods We studied five male cynomolgus monkeys with ischaemic stroke. TMS-MEP, cranial MRI, behavioural assessment, neurological scales and pathology were applied.Results Elevated resting motor threshold (RMT) (p<0.05), decreased TMS-MEP amplitudes (p<0.05) and negative RMT lateralisation were detected in both the affected motor cortex (AMC) and the paretic side median nerve (PMN) at 2 weeks poststroke. Disturbed structure and loose arrangement of myelin sheaths were observed in the PMN through H&E staining and LFB staining at 12 weeks poststroke. The primate Rankin Scale (used for assess the stroke prognosis) scores at 2–12 weeks after middle cerebral artery occlusion were [1, (1; 3)], [1, (1;2)], [1, (1; 1.5)] and [1, (1; 1.5)], respectively. The RMT and RMT lateralisation (AMC) were predictors of stroke prognosis, and the RMT lateralisation of PMN and latency of AMC were predictors of motor impairment.Conclusions Both upper motor neuron (UMN) and LMN pathway excitability is reduced after stroke, and structural damage in median nerve 12 weeks after stroke occur. In addition, RMT and RMT lateralisation are predictors of stroke prognosis and motor impairment.Data are available on reasonable request.