Abstract TP44: Brain Areas Affected by Severity of Vascular Disease as Characterized by fMRI Measures

Abstract

Background: Vascular disease has the potential of imposing varying degrees of structural, as well as functional changes onto the brain. In this study, we examined the effect of three levels of vascular disease: mild (normal aging), moderate (patient with risk factors for stroke), and severe (stroke patient), and explored the functional activity differences in these three groups using resting state fMRI. While many have reviewed rsfMRI with functional connectivity, we examined the fALFF (fractional amplitude of low frequency fluctuation), reflecting the intensity of the region’s spontaneous brain activity. Methods: 14 stroke patients (avg. age = 64.3, 5F), 8 patients with risk factors for stroke (avg. age=67.3, 3F) were recruited and imaged within 7 days of their hospital admissions for clinical symptoms. 15 aging normals or mild vascular disease subjects (avg. age = 59.6, 9F) were also recruited. A ten minute eyes-closed resting-state fMRI scans were collected with a 3T GE scanner. fALFF quantification were computed using the REST toolkit. Identified clusters are significant at p<0.05, trending at p<0.10, corrected for multiple comparisons. Results: Compared to aging normals, moderate vascular disease patients demonstrated a trending decrease in fALFF activity over the medial prefrontal cortex, rostral right superior frontal gyrus and left middle temporal cortex, and a significant increase in the cerebellum. With more severe vascular disease, those trending regions became significant. The activity over the cerebellum amplified and three additional cortical regions became disrupted or showed a decrease in fALff: left middle frontal gyrus, precuneus and right insula. The left precentral gyrus demonstrated an increase in fALff activity. Conclusions: Though the sample size is limited, this study suggests a consistent pattern of cortical fALFF activity changes as a result of increasing vascular disease. The left middle temporal, medial prefrontal cortex and right superior frontal gyrus are areas most susceptible for disruption. With a more severe vascular disease, the left middle frontal gyrus, precuneus and right insula become disrupted additionally. Moreover, the cerebellum becomes markedly more active with increasing vascular disease.