Longitudinal analysis of brain recovery after mild traumatic brain injury based on groupwise consistent brain network clusters

Abstract

Traumatic brain injury (TBI) affects over 1.5 million Americans each year, and more than 75% of TBI cases are classified as mild (mTBI). Several functional network alternations have been reported after mTBI; however, the network alterations on a large scale, particularly on connectome scale, are still unknown. To analyze brain network, in a previous work, 358 landmarks named dense individualized common connectivity based cortical landmarks (DICCCOL) were identified on cortical surface. These landmarks preserve structural connection consistency and maintain functional correspondence across subjects. Hence DICCCOLs have been shown powerful in identifying connectivity signatures in affected brains. However, on such fine scales, the longitudinal changes in brain network of mTBI patients were complicated by the noise embedded in the systems as well as the normal variability of individuals at different times. Faced with such problems, we proposed a novel framework to analyze longitudinal changes from the perspective of network clusters. Specifically, multiview spectral clustering algorithm was applied to cluster brain networks based on DICCCOLs. And both structural and functional networks were analyzed. Our results showed that significant longitudinal changes were identified from mTBI patients that can be related to the neurocognitive recovery and the brain’s effort to compensate the effect of injury.