Measuring recovery in new learning and memory following traumatic brain injury: a mixed-effects modeling approach.

Patterns of recovery from traumatic brain injury (TBI) vary greatly across individuals. Using archival data from the Traumatic Brain Injury Model Systems, recovery of memory following TBI as measured by scores on the Rey Auditory Verbal Learning Test (RAVLT) through 5 years postinjury was examined via mixed-effects modeling. Individual-level variables of age and posttraumatic amnesia duration were significant predictors of 1-year RAVLT total score. None of the variables examined predicted the trajectory of memory recovery after 1 year. Mixed-effects analyses can be helpful in determining the effect of intervention while allowing for missing data across time points.