Cortical Network Topological Modifications Underlie Clinical Evolution in the Acute Phase of Ischemic Stroke

BackgroundFollowing stroke, brain networks can be described by strength of local connections (clustering coefficient [<i>C</i>w]) and strength of global interconnections (path length [<i>L</i>w]) between nodes, and their balance (Small-worldness [<i>S</i>w]). <i>Objective</i>. To identify electroencephalography (EEG) networks predicting clinical evolution in stroke through a multicenter cross-sectional study.MethodsWe consecutively recruited 87 anterior circulation ischemic stroke patients. We obtained resting-state EEG (31 electrodes, 10-10 system) within 24 hours from stroke (<i>T</i>0) and at discharge from stroke unit (4-10 days after stroke; <i>T</i>1). EEG data were elaborated with EEGLAB and Lagged Linear Coherence among cortical sources of EEG signals was analyzed using eLORETA. We performed a multiple linear regression with National Institutes of Health Stroke Scale (NIHSS) at <i>T</i>0 and <i>T</i>1 as dependent variables and <i>C</i>w, <i>L</i>w, and <i>S</i>w of delta, theta, and alpha networks as independent variables.ResultsWe found a negative association between alpha1 <i>S</i>w and NIHSS at <i>T</i>0 (β = -.232, <i>P</i> = .04) meaning that the lower is alpha efficiency the higher is clinical severity and a positive association between delta <i>S</i>w and NIHSS at <i>T</i>1 (β = .423, <i>P</i> < .001) meaning that the higher is delta efficiency the higher is clinical severity. We found positive association between delta <i>S</i>w at <i>T</i>0 and NIHSS at <i>T</i>1 (β = .259, <i>P</i> = .02), meaning that the higher is delta efficiency in the hyperacute phase the higher is clinical severity at <i>T</i>1.ConclusionsA higher delta <i>S</i>w within 24 hours after stroke is associated to higher NIHSS within 10 days. Delta brain network rearrangement in the hyperacute phase is a potential neurophysiological measure to be integrated in multi-modal prognostic models.