Alterations of Cerebral Blood Flow Network in Behavioral Variant Frontotemporal Dementia patients with and without Apathy.

Apathy is one of the core symptoms in behavioral variant of frontotemporal dementia (bvFTD), and increases patient's morbidity and caregiver's distress. In this study, we applied a graph theoretical analysis (GTA) to analyze the topological properties of cerebral blood flow (CBF) network in 64 bvFTD patients with and without apathy (47 bvFTD-apathy and 17 bvFTD-woapathy, respectively), and 20 normal controls (NCs) based on single photon emission tomography (SPECT). Compared with the NCs, both the bvFTD groups preserved global function and typical features of small-worldness, but exhibited the loss of hubs mainly distributed in the prefrontal cortex (PFC). Compared with bvFTD-woapathy, the bvFTD-apathy group exhibited additional loss of hubs in the ventral PFC areas, middle cingulate cortex, limbic and paralimbic system, and subcortical regions, but recruited hubs in the areas of angular gyrus, precuneus and posterior cingulate cortex. Overall, our findings support the hypothesis that the disruption of frontostriatal circuit is associated with apathy in bvFTD.