By Alexander E. Merkler, MD, MS
Assistant Professor of Neurology and Neuroscience, Weill Cornell Medical College, and Assistant Attending Neurologist, New York-Presbyterian Hospital
SYNOPSIS: The majority of patients with moderate to severe traumatic brain injury who survive and are treated in acute rehabilitation centers will recover consciousness.
SOURCE: Kowalski RG, Hammond FM, Weintraub AH, et al. Recovery of consciousness and functional outcome in moderate and severe traumatic brain injury. JAMA Neurol 2021;78:548-557.
There are approximately 2.9 million emergency department visits for head trauma each year in the United States. In addition, there are 61,000 traumatic brain injury (TBI)-related deaths in the United States each year. Most of these deaths were in patients who experienced a moderate to severe TBI.1 The majority of this mortality may be a consequence of withdrawal of life-sustaining therapy, which in part may be caused by persistent disturbance in consciousness.1 However, few data exist regarding the recovery of consciousness in patients with moderate to severe TBI.
In the current study, Kowalski et al evaluated the factors associated with recovery of consciousness and independence among patients with moderate to severe TBI using data from the Traumatic Brain Injury Model Systems National Database, a 30-year prospective, multiyear, longitudinal database.2 A total of 17,470 patients with moderate to severe TBI were included in the study. The median age at injury was 39 years, and 74% were male. Among these patients, 57% had an initial loss of consciousness and 12% had a disorder of consciousness (defined as not following commands) by the time they were admitted to inpatient rehabilitation. Among these 2,058 patients who had a disorder of consciousness, 82% recovered consciousness during inpatient rehabilitation. Factors associated with recovery of consciousness included absence of intraventricular hemorrhage and intracranial mass effect. Among the patients admitted to inpatient rehabilitation with a disorder of consciousness, 40% became fully or semi-independent during inpatient rehabilitation. There were differences in outcomes across the 30-year study period.
COMMENTARY
This study adds to the growing body of data suggesting TBI is not a “one-size-fits-all” type of disorder. Prior work has shown that patients who seemingly do not appear conscious based on standard clinical tests may indeed have preserved covert consciousness.3,4 The current paper suggests that consciousness may recover over time and that patients with moderate to severe TBI may have a good outcome yet. Making hasty, life-or-death decisions in patients with TBI may be a mistake.
Limitations of this study include the article’s definition of a disorder of consciousness, which was based on the lack of ability to follow commands. It is possible that some patients determined to have a disorder of consciousness may not have been in a coma, but instead were aphasic or encephalopathic. Second, there may be a selection bias. Only patients who survived the acute hospitalizations and were discharged to inpatient rehabilitation were included in the analysis. Thus, it remains uncertain whether patients who died during the acute hospitalization or were sent to a non-rehabilitation center, such as a nursing home, would have regained consciousness. Finally, although the article contends that there may be a self-fulfilling prophecy of withdrawal of care in patients with TBI, this cannot be proven since the population included only patients who survived to inpatient rehabilitation. Thus, the chance of recovery of consciousness may have been significantly lower if all patients with moderate to severe TBI were followed.
Recovery of consciousness may be delayed in patients with moderate to severe TBI. Good outcomes still are possible even in patients with moderate to severe TBI with delayed recovery of consciousness.
REFERENCES
- Centers for Disease Control and Prevention. Traumatic Brain Injury & Concussion. TBI Data. https://www.cdc.gov/traumaticbraininjury/data/
- Kowalski RG, Hammond FM, Weintraub AH, et al. Recovery of consciousness and functional outcome in moderate and severe traumatic brain injury. JAMA Neurol 2021;78:548-557.
- Edlow BL, Chatelle C, Spencer CA, et al. Early detection of consciousness in patients with acute severe traumatic brain injury. Brain 2017;140:2399-2414.
- Monti MM, Vanhaudenhuyse A, Coleman MR, et al. Willful modulation of brain activity in disorders of consciousness. N Engl J Med 2010;362:579-589.
