Descriptive modeling of longitudinal outcome measures in traumatic brain injury: a National Institute on Disability and Rehabilitation Research Traumatic Brain Injury Model Systems study.

Establishing accurate mathematical models of outcome measures is essential in understanding change throughout the rehabilitation process. The goal of this study is to identify the best-fitting descriptive models for a set of commonly adopted outcome measures found within the Traumatic Brain Injury Model Systems National Database where the modeling is based on data submission through 2011 and the complete range of recorded time points since injury for each individual, where time points range from admission to rehabilitation to 20 years postinjury. The statistical methodology and the application of the methodology contained herein may be used to assist researchers and clinicians in (1) modeling the outcome measures considered, (2) modeling various portions of these outcomes by stratification and/or truncating time periods, (3) modeling longitudinal outcome measures not considered, and (4) establishing models as a necessary precursor in conducting individual growth curve analysis.