Arcuate Fasciculus Subsegment Impairments Distinctly Associated with Memory and Language Deficits in Acute Mild Traumatic Brain Injury Patients

In acute mild traumatic brain injury (mTBI), the injury-related axonal swelling leads to white matter fiber bundle impairments, closely related to the memory and language deficits commonly shown in the patients. The arcuate fasciculus (AF) plays a central role in verbal learning and language function but could be functionally heterogeneous along the fiber tract. In this study, 25 patients with acute mTBI (<48 h after trauma) and 33 age- and sex-matched healthy controls (HCs) were included. Impaired verbal memory and language functions were shown in the patient group compared with the HCs. Combined diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI) were applied to investigate the altered diffusion measure profiles of the AF tracts and the associated functional features. The fractional anisotropy (FA) in the right AF temporal subsegment of the mTBI group was negatively associated with the patient verbal memory function, whereas a positive correlation was found in the HC group. On the other hand, the correlation between the FA in the right AF frontal subsegment and the language function in HCs diminished in the patient group. Moreover, the functional connectivity between the inferior frontal gyrus and the middle occipital gyrus decreased, and its correlation with language function in HCs was absent in the patients with mTBI. Our work provides new insights into the understanding of the structural and functional heterogeneity of the AF tracts as well as the distinct associations of its subsegment impairments with verbal memory and language function deficits in patients with acute mTBI.