Effect of amantadine on vegetative state after traumatic brain injury: a functional magnetic resonance imaging study

Objective We assessed the use of functional magnetic resonance imaging (fMRI) to observe residual brain function and responsiveness to amantadine in a patient in a vegetative state (VS) following traumatic brain injury. Method We observed cerebral cortex activation in a 52-year-old man in a VS, and in a healthy individual using fMRI during passive listening and motor-imagery tasks. The patient received oral amantadine for 3 months. fMRI was repeated after treatment. Results Activation around the left insular regions occurred during stimulation by a familiar voice, and activity in the left temporal and bi-occipital cortices occurred during stimulation by a familiar/unfamiliar voice. Activity in the bilateral frontal and parietal cortices occurred during the motor-imagination task. Brain cortex activation was reduced in the VS patient compared with the healthy volunteer. However, the patient responded to certain auditory stimuli and motor imagery, suggesting that he retained some intact auditory and motor cortical functions. fMRI scans after 3 months of treatment showed increased activation of brain areas corresponding to task instructions. Conclusion fMRI could be used to observe the effects of amantadine on brain function, and to aid the diagnosis and prognostic prediction in VS patients in terms of recovery and rehabilitation planning.