Assessing Acute Middle Cerebral Artery Ischemic Stroke by Quantitative Electric Tomography

Abstract

This paper focuses on the application of quantitative electric tomography (qEEGT) to map changes in EEG generators for detection of early signs of ischemia in patients with acute middle cerebral artery stroke. Thirty-two patients were studied with the diagnosis of acute ischemic stroke of the left middle cerebral artery territory, within the first 24 hours of their clinical evolution. Variable Resolution Electrical Tomography was used for estimating EEG source generators. High resolution source Z-spectra and 3- dimensional images of Z values for all the sources at each frequency were obtained for all cases. To estimate statistically significant increments and decrements of brain electric activity within the frequency spectra, the t-Student vs. Zero test was performed. A significant increment of delta activity was observed on the affected vascular territory, and a more extensive increment of theta activity was detected. A significant alpha decrement was found in the parieto-occipital region of the affected cerebral hemisphere (left), and in the medial and posterior region of the right hemisphere. These findings suggest that qEEGT Z delta images are probably related to the main ischemic core within the affected arterial territory; penumbra, diaschisis, edema, might explain those observed theta and alpha abnormalities. It was concluded that qEEGT is useful for the detection of early signs of ischemia in acute ischemic stroke.

Delta–alpha ratio correlates with level of recovery after neurorehabilitation in patients with acquired brain injury

“…Although this finding is observed in a small sample, it is consistent with high increases in delta activity and decreases in alpha activity in non-acute ABI patients reported by Nuwer et al (1987), and others (Tolonen, 1984;Machado et al, 2004;Finnigan et al, 2007). Our findings also extend the significance of this index to the chronic phase when sequelae are established.…”

Early prediction of delayed cerebral ischemia in subarachnoid hemorrhage based on quantitative EEG: A prospective study in adults

“…Stuart et al also reported the alpha-delta ratio to be most predictive for DCI in intracortical EEG (Stuart et al, 2010). A possible explanation for the divergent findings may be the hypothesis corroborated by Machado et al (Machado et al, 2004) who applied qEEG to patients with MCA ischemic strokes and found delta power increases to be related to the ischemic core while the tissue at risk, penumbra, and edema were characterized by alpha and theta alterations. Correspondingly, the alpha decrease in our study marked the early point where perfusion dropped below a critical level, generating tissue at risk of, but not yet persistent, ischemic infarction.…”

Using Continuous Electroencephalography in the Management of Delayed Cerebral Ischemia Following Subarachnoid Hemorrhage

“…The derivation of the CAI in our study was based on previous research which identified changes in the alpha band during ischemia notably in the penumbric region [14,15,34]. However, the use of alternate power bands and their ratios raises the possibility of a wide array of quantitative parameters that may be optimal markers of DCI [4,[34][35][36].…”

“…However, the use of alternate power bands and their ratios raises the possibility of a wide array of quantitative parameters that may be optimal markers of DCI [4,[34][35][36].…”