Reemergence of the language network during recovery from severe traumatic brain injury: A pilot functional MRI study.

The study is a pilot with only 8 patients who returned for follow-up. No methods or analyses were pre-registered. There were no patients with persistently impaired basic language function for comparison, so the findings cannot say what happens when language recovery fails. Acute scans were performed in the ICU, often soon after injury, and 6 patients received sedative, anxiolytic, or analgesic medications before or during the acute scan. Patients moved more in the scanner than healthy controls, and two exceeded the usual high-motion threshold. Lesion location and age varied across patients, and the study could not determine whether fMRI responses were affected by specific lesion distributions or total injured tissue volume. The regions of interest were deliberately broad, which may include voxels outside the canonical language network and increase false-positive responses. The fMRI task was short and used only passive listening to a speech clip, so it did not test naming, responsive naming, or verbal fluency. The study cannot separate recovery of consciousness from recovery of language function because both co-occurred in the follow-up patients. The authors cannot distinguish reorganization from reemergence without pre-injury fMRI data. The whole-brain and lower-threshold comparisons are exploratory because of low statistical power.

The authors declared no conflicts of interest. The article is listed as supported by NIH extramural research and non-U.S. government research support.

Do not conclude that fMRI can predict language recovery or that this network change caused recovery. The study followed eight patients who returned, all had recovered basic language, and there were no patients with persistently impaired language for comparison. Acute scans were also affected by sedation and motion.