Altered Resting-State Cortical EEG Oscillations in Patients With Severe Asymptomatic Carotid Stenosis

Abstract

Asymptomatic carotid stenosis is characterized by altered cerebral hemodynamics and cognitive impairment, but the underlying neurophysiological mechanism remains unclear. To elucidate the alterations of cortical activities, resting-state electrophysiological activities were recorded from patients with mild (<30%; n=10; age 57-85 years), moderate (30% to 50%; n=11; age 66-88 years), and severe (>50%; n=8; age 67-91 years) carotid stenosis. The current density and oscillatory power of the cortical sources were analyzed using the minimum norm estimates method combined with fast Fourier transform analysis. Our results indicate that the cortical current density among regions of the brain was similar, irrespective of the degree of carotid stenosis. With regard to the cortical oscillations, augmented theta activities in the bilateral parietal, left temporal, and left occipital regions and attenuated alpha activities in the bilateral frontal and right central regions were obtained in patients with severe asymptomatic carotid stenosis. We suggest that the source-based cortical oscillations at theta and alpha bands might reflect the alterations of the brain activities and characterize the altered neurophysiological mechanism of the brain with at least 50% occlusion of the carotid artery. Further longitudinal studies with larger populations are warranted to verify the present findings.

Normalization of reduced functional connectivity after revascularization of asymptomatic carotid stenosis

“…This introduces confounding factors due to the hemodynamical dependency of the BOLD signal that is affected by cerebrovascular disease such as chronic hypoperfusion. 15,16 One EEG pilot study provided first findings of alterations in cortical activity in patients with severe carotid stenosis, 17 data analysis, however, was restricted to spectral power analysis in low-density EEG, hence not investigating brain connectivity. Furthermore, it is not known whether treatment of carotid stenosis has an impact on oscillatory functional connectivity, and it has not been studied yet if alterations of brain oscillations hypothesized to come along with carotid stenosis are reversible after revascularization.…”

Screening of genes related to the atherosclerotic plaque stability in patients with asymptomatic carotid stenosis

“…Carotid stenosis is the narrowing of the carotid arteries due to atherosclerosis 1 . The disease begins with an endothelial dysfunction leading to a chronic inflammatory response.…”