Difference in the ascending reticular activating system between vegetative and minimally conscious states following traumatic brain injury.

Objectives We investigated differences in the ascending reticular activating system (ARAS) between vegetative state (VS) and minimally conscious state (MCS) in patients with traumatic brain injury (TBI) by using diffusion tensor tractography. Methods We recruited TBI patients and normal subjects. We reconstructed the lower ARAS and five parts of upper ARAS [prefrontal cortex (PFC), premotor cortex, primary motor cortex, primary somatosensory cortex, and posterior parietal cortex]. Results Significant differences were observed in the fractional anisotropy (FA) and fiber number (FN) values of the five parts of upper ARAS between the VS and control groups and between the MCS and control groups (P 0.05). The FA and FN values of the PFC in the upper ARAS were significantly different between the VS and MCS groups (P 0.05). Conclusion The results indicate that the prefrontal portion of the upper ARAS is the critical area for distinguishing between VS and MCS in patients with TBI.