As listed in Table 1, each patient’s recovery is categorized according to five levels: death persistent vegetative state severe disability requiring care moderate disability and mild disability.

Since its first reporting in 1975, by Jennett and Bond, the Glasgow Outcome Scale (GOS) has been used as a means to rank outcomes in patients with brain injury. They also were largely developed and validated in hybrid populations that incorporated patients with both moderate and severe TBI ( 13). Such instruments tend to over-estimate rates of mortality and severe disability, however, and fail to address such potential outcomes like time to consciousness, overall cognitive function, and return to work or school. More recently, various composite instruments - like the Trauma and Injury Severity Score (TRISS), Corticosteroid Randomization After Significant Head Injury (CRASH), and International Mission for Prognosis and Analysis of Clinical Trials in TBI (TBI-IMPACT) - have been developed and validated ( 12). Traditionally, the Glasgow Coma Scale (GCS) has been used by clinicians to predict the likelihood of patient survival and recovery. Questions like ‘will the patient regain consciousness’, ‘will the patient be permanently disabled and, if so, to what degree’ and ‘will the patient be able to return to school or work’ abound. For obvious reasons, physicians treating patients with sTBI often are called to predict their patient’s prognosis, and not just with respect to survival, so that it can be used for treatment decisions, the allocation of resources, and communications with loved ones and other caregivers ( 10, 11). On the other hand, up to half of patients experience significant recovery, to the point where they become able to take care of themselves, and perhaps even return to work or school ( 9). Severe traumatic brain injury (sTBI) is a common cause of death and disability worldwide ( 1- 4), with 14- and 30-day mortality rates frequently in the 15-30% range ( 2, 5- 8).

Post traumatic amnesia score