Functional connectivity in the fronto-parietal network: an indicator of pre-operative cognitive function and cognitive outcome following surgery in patients with glioma

• Published in: World neurosurgery
• Main Authors: Lang, Stefan, MD, Gaxiola-Valdez, Ismael, Msc, Opoku-Darko, Michael, MD, Partlo, Lisa A., PhD, Goodyear, Bradley G., PhD, Kelly, John J.P., MD PhD, Federico, Paolo, MD PhD
• Format: Journal Article
• Language: English
• Published: 2017
• Subjects: Neurosurgery; PPC; cognition; blood oxygen level dependent; FPN; prefrontal cortex; rs-fMRI; neurooncology; resting state fMRI; NIHTB-CB; PFC; posterior parietal cortex; ROI; fMRI; fronto-parietal network; region of interest; resting-state functional connectivity; BOLD; neurosurgery; functional magnetic resonance imaging; National Institute of Health Toolbox Cognitive Battery
• ISSN: 1878-8750
• DOI: 10.1016/j.wneu.2017.05.149

Abstract Background Patients with diffuse glioma are known to have impaired cognitive functions pre-operatively. However, the mechanism of these cognitive deficits remains unclear. Resting state functional connectivity in the fronto-parietal network (FPN) is associated with cognitive performance in healthy subjects. For this reason, it was hypothesized that functional connectivity of the FPN would be related to cognitive functioning in patients with glioma. To assess this relationship, pre-operative cognitive status was correlated to patient specific connectivity within the FPN. Further, we assessed whether connectivity could predict neuropsychological outcome following surgery. Methods Sixteen patients with diffuse glioma underwent neuropsychological assessment and pre-operative fMRI using task (n-back) and resting state scans. Thirteen patients had post-operative cognitive assessment. An index of patient-specific functional connectivity in the FPN was derived by averaging connectivity values between two prefrontal and two parietal cortex regions defined by activation during the n-back task. The relationship of these indices with cognitive performance was assessed. Results Higher average connectivity within the FPN is associated with lower composite cognitive scores. Higher connectivity of the parietal region of the tumor-affected hemisphere is associated specifically with lower fluid cognition. Lower connectivity of the parietal region of the non-tumor hemisphere is associated with worse neuropsychological outcome one month after surgery. Conclusion Resting state functional connectivity between key regions of the FPN is associated with cognitive performance in patients with glioma and is related to cognitive outcome following surgery.