Behavioral markers of recovery of consciousness after severe brain injury

Patients with an altered state of consciousness (i.e., coma, unresponsive wakefulness syndrome/vegetative state [UWS/VS], minimally conscious state [MCS] and emergence from the MCS [eMCS]) following severe brain injury are highly exposed to the risk of misdiagnosis. Detecting the transition from an unconscious to conscious state is critically important to clinical management, disposition planning and family counseling.
This retrospective observational study aimed at determining which behaviors signal recovery of consciousness after severe traumatic and non-traumatic brain injury and the time course to recovery of consciousness using the Coma Recovery Scale-Revised (CRS-R) in an inpatient rehabilitation hospital with a specialized disorders of consciousness (DoC) program.
Seventy-nine patients who transitioned from coma or UWS/VS to MCS or eMCS during inpatient rehabilitation were included (51 males; median age [IQR]= 48 [25.5 – 61]; TBI = 34; median time since injury at admission [IQR]: 26 [20 – 36] days). Visual pursuit was the most frequently observed behavioral sign marking recovery of consciousness (present in 37% of patients), followed by reproducible movement to command (23%) and automatic movements (22%). Ten other behaviors signaled return of conscious awareness, but these signs were first to emerge in less than 15% of cases. In 72% of the sample, the transition to conscious awareness was marked by a single behavior: visual pursuit. When two behavioral markers of consciousness emerged concurrently at time of transition (17%), visual and motor signs were most prevalent. The median time to recovery of consciousness was 44 [33 – 59] days post injury.
The transition from an unconscious to conscious state is usually marked by the emergence of a single behavioral sign of consciousness. Visual pursuit, reproducible command-following and automatic movements are the most common markers of recovery of consciousness. Clinicians should utilize assessment methods that are particularly sensitive to these behaviors to avoid early misdiagnosis and inappropriate treatment recommendations.