Early detection of consciousness after severe brain injury is critical for establishing an accurate prognosis and planning appropriate treatment.

To determine which behavioural signs of consciousness emerge first and to estimate the time course to recovery of consciousness in patients with severe acquired brain injury.

Retrospective observational study using the Coma Recovery Scale-Revised and days to recovery of consciousness in 79 patients (51 males; 34 with traumatic brain injury; median [IQR] age 48 [26–61] years; median time since injury 26 [20–36] days) who transitioned from coma or unresponsive wakefulness syndrome (UWS)/vegetative state (VS) to the minimally conscious state (MCS) or emerged from MCS during inpatient rehabilitation.

Visual pursuit was the most common initial sign of MCS (41% of patients; 95% CI [30–52]), followed by reproducible command-following (25% [16–35]) and automatic movements (24% [15–33]). Ten other behaviours emerged first in less than 16% of cases. Median [IQR] time to recovery of consciousness was 44 [33–59] days. Etiology did not significantly affect time to recovered consciousness.

Recovery of consciousness after severe brain injury is most often signalled by reemergence of visual pursuit, reproducible command-following and automatic movements. Clinicians should use assessment measures that are sensitive to these behaviours because early detection of consciousness is critical for accurate prognostication and treatment planning.