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Abstract Details

Signs of Electro-cortical Disconnection revealed by Hd-EEG in Acute Stroke Patients: a Case Study.
Epilepsy/Clinical Neurophysiology (EEG)
P10 - Poster Session 10 (8:00 AM-9:00 AM)
There are overwhelming evidences that stroke lesions induce local and remote effects beyond the site of the primary anatomical damage. These networks effects have been studied mainly via neuroimaging techniques. However, little is known about the electrocortical disconnection caused by acute stroke. Moreover, the spatial resolution has been limited by the adoption of standard EEG. 
To assess electro-cortical disconnection induced by stroke lesions in two patients with Hd-EEG study. 

128 channels Hd-EEG was recorded in two acute stroke patients (Patient 1 and Patient 2) in awake state. Patient 1 presented with aphasia and neglect in ischemic stroke involving left insula, temporal and parietal lobe. Patient 2 had mild left side paresis with evidence of extensive hypoperfusion and small multiple ischemic infarcts in right ICA occlusion. Raw data were pre-processed in MATLAB using AMICA in EEGLAB. Power spectra analysis was performed on delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz) and beta (12-25 Hz) frequencies at whole-brain level and within each hemisphere. Values were then compared between the two hemispheres (lesioned vs not lesioned) using a t-test analysis (p<0.05).  


Patient 1 had not only higher delta and theta power over temporo-parietal and posterior frontal regions but also absence of alpha power over posterior occipital regions. In addition to high delta and theta activity over a broad region including frontal and temporo-parietal areas in the hypo-perfused hemisphere, Hd-EEG in Patient 2 showed abnormal delta activity over contralateral frontal regions.  
Our findings point to the presence of electro-cortical disconnection that extends the focal lesion borders. Both patients had either delta activity or loss of alpha power in regions distant from the location of the primary local damage/hypoperfusion that was characterized by slowing. Hd-EEG may reveal network disruption in acute stroke patients in a novel and complementary way compared to neuroimaging.  
Elena Monai, MD (University of Wisconsin-Madison)
Dr. Monai has nothing to disclose.
Brinda Sevak, Other (University of Wisconsin Madison) Miss Sevak has nothing to disclose.
Klevest Gjini, MD, PhD (University of Wisconsin - Madison) The institution of Dr. GJINI has received research support from NIH.
Aaron F. Struck, MD The institution of Dr. Struck has received research support from Ceribell.
Melanie Boly, MD (UW Medical Foundation Centennial Bldg) Dr. Boly has nothing to disclose.