title: Altered Resting-State Connectivity within Executive Networks after Aneurysmal Subarachnoid Hemorrhage.
abstract: Aneurysmal subarachnoid hemorrhage (aSAH) is associated with significant mortality rates, and most survivors experience significant cognitive deficits across multiple domains, including executive function. It is critical to determine the neural basis for executive deficits in aSAH, in order to better understand and improve patient outcomes. This study is the first examination of resting-state functional Magnetic Resonance Imaging in a group of aSAH patients, used to characterize changes in functional connectivity of the frontoparietal network. We scanned 14 aSAH patients and 14 healthy controls, and divided patients into "impaired" and "unimpaired" groups based on a composite executive function score. Impaired patients exhibited significantly lower quality of life and neuropsychological impairment relative to controls, across multiple domains. Seed-based functional connectivity analysis demonstrated that unimpaired patients were not significantly different from controls, but impaired patients had increased frontoparietal connectivity. Patients evidenced increased frontoparietal connectivity as a function of decreased executive function and decreased mood (i.e. quality of life). In addition, T1 morphometric analysis demonstrated that these changes are not attributable to local cortical atrophy among aSAH patients. These results establish significant, reliable changes in the endogenous brain dynamics of aSAH patients, that are related to cognitive and mood outcomes.
authors.affiliation: Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Monica
authors.initials: M
authors.lastname: Maher
authors.affiliation: Neuroscience Research Program, Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Nathan W
authors.initials: NW
authors.lastname: Churchill
authors.affiliation: Neuroscience Research Program, Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Airton Leonardo
authors.initials: AL
authors.lastname: de Oliveira Manoel
authors.affiliation: Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Graham
authors.affiliation: The Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada; Division of Neurosurgery, St. Michael's Hospital, Toronto, Ontario, Canada; Division of Neurosurgery, Department of Neurosurgery, University of Toronto, Toronto, Ontario, Canada.
authors.forename: R Loch
authors.initials: RL
authors.lastname: Macdonald
authors.affiliation: The Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada; Division of Neurosurgery, St. Michael's Hospital, Toronto, Ontario, Canada; Division of Neurosurgery, Department of Neurosurgery, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Tom A
authors.initials: TA
authors.lastname: Schweizer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003071:Cognition; D056344:Executive Function; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications*; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology*; D009929:Organ Size; D017397:Prefrontal Cortex / Q000473:pathology / Q000503:physiopathology; D011788:Quality of Life; D012146:Rest; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000473:pathology / Q000503:physiopathology*; D055815:Young Adult