Behavioral signs associated with recovery of consciousness after severe brain injury

Objectives: To determine which features of minimally conscious state (MCS) emerge first in patients transitioning from the vegetative state (VS) to MCS following severe traumatic and non-traumatic brain injury.
Design: Retrospective observational study.
Setting: Inpatient Setting with a Specialized Disorders of Consciousness (DoC) program.
Participants: 65 patients who met criteria for MCS for the first time during their inpatient stay (44 male; mean age+/-SD = 43.6+/-19.8; TBI = 31; median time since injury [IQR]: 42 days [32 – 54]).
Interventions: N/A
Main Outcome Measures: MCS behaviors detected on the Coma Recovery Scale-Revised (CRS-R).
Results: At transition from VS to MCS, visual pursuit was the most frequently observed MCS behavior (39% of patients), followed by automatic response (32%), reproducible movement to command (29%), intentional communication (19%) and visual fixation (12%). Each one of the remaining MCS behaviors (i.e., localization to pain, object manipulation, intelligible verbalization, object recognition, object localization and consistent movement to command) was present in less than 5% of the patients. In patients who showed only one behavioral sign of consciousness at emergence from VS (71% of sample), visual pursuit was most prevalent, occurring in 41% of cases. In patients who demonstrated two MCS behaviors concurrently at time of emergence (9% of sample), transitional features involved visual and motor functions in 44% of cases. Only 2% of patients demonstrated MCS behaviors across all 5 CRS-R subscales that include MCS features.
Conclusions: Patients with DoC transitioning from VS to MCS typically recover cognitively-mediated visual and motor behaviors. Most patients initially demonstrate only one behavioral sign of consciousness, highlighting the importance of performing comprehensive serial assessments in this population.