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Poster A57, Wednesday, November 8, 10:30 – 11:45 am, Harborview and Loch Raven Ballrooms

Verbal IQ is determined by brain health, which is modulated by cardiovascular risk factors

Barbara Khalibinzwa Marebwa1, Robert J. Adams1, Julius Fridriksson2, Gayenell Magwood1, Leonardo Bonilha;1Medical University of South Carolina, 2University of South Carolina

The integrity of fiber connectivity in structural networks supports cognitive processing within the brain and can be used as a measure of brain health beyond current neuropsychological testing. We aimed to quantify the relationship between verbal IQ in older adults and the disruption of white matter network architecture using high resolution whole brain structural connectomes constructed from diffusion images of 60 participants either with no cardiovascular (CV) risk factors, or at least one CV risk factor. We measured white matter network organization using Newman’s modularity algorithm and determined the effect of CV risk factors on the network architecture, and their relationship with verbal IQ. We hypothesized that verbal IQ in older adults is modulated by CV risk factors through the disruption of the white matter network architecture, which can be therefore understood as a biological measure of brain health. We found evidence of disruption via fragmentation of the community structure. Greater network fragmentation (high modularity) was significantly associated with decreased verbal IQ (r = -0.3003, p = 0.0099; r = -0.3422, p = 0.0037 for the left and right hemisphere respectively). Participants with CV risk factors had more modules, and significantly higher network modularity compared to healthy controls. We also investigated short-, mid- and long- range fibers and found evidence of mid- and long range fiber loss in participants with CV risk factors. Fiber loss was also significantly associated with participants with CV risk factors, and with decreased verbal IQ (r = 0.4624, p < 10-4; r = 0.4704, p < 10-4 for the left and right hemisphere respectively). Our findings show a pattern of network fragmentation and fiber loss in participants with cardiovascular risk factors, which is associated with lower verbal IQ. We propose that the disorganization of the community structure is a consequence of long range fiber loss, and demonstrate that white matter topological organization measured from the connectome could be used as a personalized biomarker to inform on individual brain health in relationship with language.

Topic Area: Computational Approaches

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