Prospective comparison of acute confusion severity with duration of post-traumatic amnesia in predicting employment outcome after traumatic brain injury.

Abstract

Measurement of the duration of post-traumatic amnesia (PTA) is common practice, serving as an important index of the severity of traumatic brain injury (TBI) and a predictor of functional outcome. However, controversy exists regarding the nature of PTA; some studies indicate that it is a confusional state with symptoms that extend beyond disorientation and amnesia. To evaluate the contribution of the severity of acute confusion 1 month after TBI to prediction of employment at 1 year after injury, comparing it with PTA duration. Prospective study involving 171 participants with complete data, who met the study criteria, from 228 consecutive TBI Model System admissions. Outcome measures included weekly administration of the Delirium Rating Scale-Revised-98 (DelRS-R98) to measure the severity of acute confusion. Evaluations closest to 1 month after injury were used for study purposes. Duration of PTA was defined as the interval from injury until two consecutive Galveston Orientation and Amnesia Test scores of > or = 76 were obtained within a period of 24-72 h. Univariable and multivariable logistic regression were used to predict employment status at 1 year after injury. Age, education and DelRS-R98 were significant predictors accounting for 34% of outcome variance. Individuals with greater confusion severity at 1 month after injury, older age and lower levels of education were less likely to be employed at 1 year after injury. Severity of confusion was more strongly associated with employment outcome (r(s) = -0.39) than was PTA duration (r(s) = -0.34). In addition to demographic indices, severity of acute confusion makes a unique contribution to predicting late outcome after TBI.