Abstract W MP38: Resting-state Functional Connectivity after Aneurysmal Subarachnoid Hemorrhage
BACKGROUND: Up to 83% of aneurysmal subarachnoid hemorrhage (aSAH) survivors experience cognitive deficits - particularly in the domain of executive functioning, which encompasses skills necessary for everyday functioning. The neural correlates of these deficits have not yet been investigated. Resting-state functional magnetic resonance imaging (rs-fMRI) is an imaging technique to investigate functional connectivity between brain regions at rest - that is, without the use of a stimulation task. Spontaneous neural activity at rest is an intrinsic property of healthy brains and can be disrupted by various pathologies. In rs-fMRI, deviations from the norm (increases or decreases) are abnormalities indicative of the existence of impairments. HYPOTHESIS: We hypothesized that aSAH patients will exhibit altered resting-state functional connectivity within frontal brain networks that would map onto impaired performance on tests of executive functioning relative to matched healthy controls. METHODS: 14 aSAH patients and 11 healthy controls matched on age, education and gender were included. To differentiate between patients with good and poor cognitive outcome, a composite Executive Function score was generated using the z-scores of executive tests, and patients with negative composites were then classified as ‘Impaired’ for further analyses. RESULTS: The Impaired group scored significantly worse than both Controls and Unimpaired patients on 10 measures of executive functioning. Resting-state connectivity between the right dorsolateral prefrontal cortex (DLPFC) and the left superior frontal gyrus (SFG) was significantly increased in the ‘Impaired’ patients and this connection covaried significantly with composite executive scores. Increased connectivity between the left DLPFC and right precuneus was seen in the impaired patients relative to controls, covarying significantly with reduced mood scores. CONCLUSIONS: The aberrant connection between the right DLPFC and left SFG may underlie executive impairments after aSAH. This imaging modality could be explored as a potential diagnostic tool to identify cognitive impairment in aSAH patients and direct them to appropriate rehabilitation programs for improved cognitive outcomes.
Author Disclosures: M.E. Maher: None. A. de Oliveira Manoel: None. S. Graham: None. R. Macdonald: None. T.A. Schweizer: None.
- © 2015 by American Heart Association, Inc.