OBJECTIVES: To develop predictive models of recovery from the vegetative state 
(VS) and minimally conscious state (MCS) after traumatic brain injury (TBI) and 
to gather preliminary evidence on the impact of various psychotropic medications 
on the recovery process to support future randomized controlled trials. Design 
Longitudinal observational cohort design, in which demographic information, 
injury and acute care history, neuroimaging data, and an initial Disability 
Rating Scale (DRS) score were collected at the time of study enrollment. Weekly 
follow-up data, consisting of DRS score, current psychoactive medications, and 
medical complications, were gathered until discharge from inpatient 
rehabilitation.
SETTING: Seven acute inpatient rehabilitation facilities in the United States 
and Europe with specialized programs for treating patients in the VS and MCS.
PARTICIPANTS: People with TBI (N=124) who were in the VS or MCS 4 to 16 weeks 
after injury.
INTERVENTIONS: Not applicable.
MAIN OUTCOME MEASURES: DRS score at 16 weeks after injury and time until 
commands were first followed (among those participants demonstrating no command 
following at study enrollment). Results DRS score at enrollment, time between 
injury and enrollment, and rate of DRS change during the first 2 weeks of 
poststudy observation were all highly predictive of both outcomes. No variables 
related to injury characteristics or lesions on neuroimaging were significant 
predictors. Of the psychoactive medications, amantadine hydrochloride was 
associated with greater recovery and dantrolene sodium was associated with less 
recovery, in terms of the DRS score at 16 weeks but not the time until commands 
were followed. More detailed analysis of the timing of functional improvement, 
with respect to the initiation of amantadine provided suggestive, but not 
definitive, evidence of the drug's causal role.
CONCLUSIONS: These findings show the feasibility of improving outcome prediction 
from the VS and MCS using readily available clinical variables and provide 
suggestive evidence for the effects of amantadine and dantrolene, but these 
results require confirmation through randomized controlled trials.