The mechanisms underlying recovery of language function after severe TBI are poorly understood, and the functional neuroanatomic correlates of language recovery have not been characterized.

To identify neurophysiological changes in the language network during recovery from acute severe traumatic brain injury (TBI).

We performed a longitudinal, prospective, observational study of 9 patients with acute severe TBI who recovered language function by six months post-injury. Patients underwent functional MRI (fMRI) with a spoken language stimulus as soon as they were stable to travel to the scanner. We assessed level of consciousness and language function using the Coma Recovery Scale-Revised immediately prior to fMRI. We repeated fMRI and behavioral assessments at 6 months post-injury. FMRI responses in the bilateral superior temporal gyri (STG) and bilateral inferior frontal gyri (IFG) were compared between early and follow-up scans. We also performed an exploratory whole-brain analysis to evaluate for stimulus-induced activation outside of these frontotemporal language regions.

We observed a longitudinal increase in fMRI responses to language in the right STG (p=0.01). No longitudinal changes in fMRI responses were detected in the left STG, left IFG, or right IFG. Whole-brain analysis did not reveal any longitudinal changes in fMRI responses outside of the right STG.

These longitudinal fMRI results provide initial evidence that reorganization of the language network may be a mechanism by which patients with severe TBI recover language function.