1514 - Attention-related functional network changes after mild traumatic brain injury: a longitudinal study

Objectives: To investigate the cross-sectional and longitudinal changes in functional network connectivity (FNC) and structural network in the dorsal attention network (DAN), ventral attention network (VAN), and default mode network (DMN) after mild traumatic brain injury (mTBI).

Design: Thirty-one individuals with mTBI (43.7±14.2 years) were scanned twice: within a month and three months after injury. Matched controls (43.2±13.7 years) were scanned twice at similar intervals. After preprocessing the rs-fMRI data (Kim et al., 2022), two DAN, two VAN, and three DMN were defined in each hemisphere (Schaefer et al., 2018) and correlation coefficient r was transformed to z between each network (Jafri et al., 2008). Probabilistic tractography was used to construct structural network with the predefined DAN, VAN, and DMN as nodes. A linear mixed effect model was used to investigate changes in FNC and structural network, with group and time as fixed effects and subjects as random effects. A streamline density map corresponding to the structural connection was generated. The relationship between the performance of attention-related tasks and the FNC or fractional anisotropy (FA) of the streamlines was examined using correlation analysis.

Results: The FNC between the DMN and VAN were decreased in the mTBI group compared to the controls, during the acute and chronic phases after injury. In contrast, the FNC between the DMN and DAN were tended to increase in the mTBI group at chronic phase after injury compared to the controls. There was a significant correlation between the performance of attention-related tasks and FNC in the mTBI group compared to the controls. Moreover, in the mTBI group, the FA of the structural connection corresponding to the FNC was not correlated with the attention performance, unlike in the control group.

Conclusions: Our findings highlight the multifaceted nature of mTBI between functional or structural brain changes and attentional impairments.