Affiliations: Division of Neurorehabilitation, Department of
Clinical Neurosciences, University Hospital of Geneva, Geneva,
Switzerland | Division of Neurology, Department of Clinical
Neurosciences, University Hospital of Geneva, Geneva, Switzerland
Note: [] Corresponding author: Sviatlana Dubovik, Division of
Neurorehabilitation, Department of Clinical Neurosciences, University Hospital
of Geneva, Geneva, Switzerland. E-mail: [email protected]
Abstract: Functional brain networks are known to be affected by focal brain
lesions. However, the clinical relevance of these changes remains unclear. This
study assesses resting-state functional connectivity (FC) with
electroencephalography (EEG) and relates observed topography of FC to cognitive
and motor deficits in patients three months after ischemic stroke. Twenty
patients (mean age 61.3 years, range 37–80, 9 females) and nineteen
age-matched healthy participants (mean age 66.7 years, range 36–88, 13
females) underwent a ten-minute EEG-resting state examination. The neural
oscillations at each grey matter voxel were reconstructed using an adaptive
spatial filter and imaginary component of coherence (IC) was calculated as an
index of FC. Maps representing mean connectivity value at each voxel were
correlated with the clinical data. Compared to healthy controls, alpha band IC
of stroke patients was locally reduced in brain regions critical to observed
behavioral deficits. A voxel-wise Pearson correlation of clinical performances
with FC yielded maps of the neural structures implicated in motor, language,
and executive function. This correlation was again specific to alpha band
coherence. Ischemic lesions decrease the synchrony of alpha band oscillations
between affected brain regions and the rest of the brain. This decrease is
linearly related to cognitive and motor deficits observed in the patients.
