Predicting Level of Independence Following Moderate to Severe Traumatic Brain Injury

Philip Schatz, Ph.D., Saint Joseph's University, Psychology Department
Douglas L. Chute, Ph.D., Drexel University University, Psychology Department


Demographic and rehabilitation outcome data were analyzed for 300 moderate and severe traumatic brain injury patients enrolled in the Pennsylvania Head Injury Program (PHIP) between 1985 and 1994. Predictive factors of outcome following traumatic brain injury were identified. We constructed a ten-point level of independence rating scale as a measure for rehabilitation outcome which included need for supervision for communication, self-care routines, basic living skills, daily living, and employment. Post-hoc interrater reliability was significantly high at .80. Multiple regression analysis identified Disability Rating Scale (DRS) scores at twelve to eighteen months post injury as the most significant predictor of level of independence up to nine years post injury. DRS scores accounted for 49% of the variance in the level of independence measure. Subjects matched for severity of injury and functional ability at discharge from primary rehabilitation were divided into groups on the basis of number of rehabilitation facilities attended. Analyses of variance revealed that subjects who attended fewer rehabilitation facilities spent significantly fewer days in primary rehabilitation and were more likely to be discharged to the care of their families. Subjects attending one to three subsequent rehabilitation facilities after acute rehabilitation showed no significant difference on level of independence ratings, DRS scores, and Rancho Los Amigos Level of Cognitive Functioning ratings up to nine years post injury. We hypothesize that subsequent rehabilitation hospitalizations do not significantly improve scores on outcome measures because these admissions occur in the absence of appropriate discharge placements following primary rehabilitation. Trends in acute and rehabilitation hospitalization statistics for TBI between 1986 and 1993 were analyzed, revealing significant decreases in mean acute care and rehabilitation length of stay (20 and 60 days, respectively) for TBI survivors, with no significant effect on level of independence.


Subjects: Subjects were 300 individuals considered to be domiciled in the state of Pennsylvania at the time of their head injury who enrolled in the Pennsylvania Head Injury Program. Inclusion in the study was contingent upon:
  • documented evidence of a traumatic brain injury
  • measureable outcome rating at two or more years post-injury

Procedures: Retrospective inspection of 300 Pennsylvania Head Injury Program files was performed, coding demographic data,injury severity and outcome scores from acute care and rehabilitation hospital discharge summaries. Glasgow Coma Scale, Disabilty Rating Scale and Functional Independence Level scores were coded from post-acute rehabilitation hospital discharge summaries and/or Pennsylvania Head Injury Program case management reports. Where specific scores were not recorded, specific information within these documents was used to extrapolate scores. .


Demographics: Demographic variables from the present study are consistent with previous head injury epidemiology studies. Demographics suggest the current sample is consistent with the population of surviviors of moderate and severe traumatic brain injury.

Predicting Level of Independence: Ratings of functional abilities at approximately 18 to 24 months post injury will provide rehabilitation professionals with a significant predictor of outcome, as measured by level of independence. Ratings of severity of head injury, such as depth of coma, length of coma, CT scan results, and length of stay on acute care hospital are not significant predictors of level of independence.

Effect of Multiple Rehabilitation Hospitalizations: Subjects attending one to four rehabilitation hospitals were matched for severity of injury and functional ability at discharge from primary rehabilitation. Subjects attending fewer rehabilitation hospitals spent significantly fewer days in primary rehabilitation, and were significantly more likely to be discharged to the care of their families. It is hypothesized that subsequent rehabilitation hospitalizations following primary rehabilitation occur in the absence of appropriate, structured discharge placements.

Trends in Rehabilitation between 1986 and 1993: Brain injured patients hospitalized in 1993 are spending 20 fewer days in acute care and 60 fewer days in primary rehabilitation, as compared to TBI patients hospitalized in 1986. In spite of decreased length of stay, no significant decline is noted in resultant level of independence.