Characterization of functional brain activity and connectivity using EEG and fMRI in patients with sickle cell disease

Sickle cell disease (SCD) is a red blood cell disorder that causes many complications including life-long pain. Treatment of pain remains challenging due to a poor understanding of the mechanisms and limitations to characterize and quantify pain. In the present study, we examined simultaneously recording functional MRI (fMRI) and electroencephalogram (EEG) to better understand neural connectivity as a consequence of chronic pain in SCD patients. We performed independent component analysis and seed-based connectivity on fMRI data. Spontaneous power and microstate analysis was performed on EEG-fMRI data. ICA analysis showed that patients lacked activity in the default mode network (DMN) and executive control network compared to controls. EEGfMRI data revealed that the insula cortex's role in salience increaseswith age in patients. EEGmicrostate analysis showed patients had increased activity in pain processing regions. The cerebellumin patients showed a stronger connection to the periaqueductal graymatter (involved in pain inhibition), and negative connections to pain processing areas. These results suggest that patients have reduced activity ofDMN and increased activity in pain processing regions during rest. The present findings suggest resting state connectivity differences between patients and controls can be used as novel biomarkers of SCD pain. (C) 2016 The Authors. Published by Elsevier Inc.