Mathematical models of cognitive recovery

Longitudinal psychological test results are used as dependant variables to explore the complex relationship between length of coma, time of testing on the recovery curve, and corresponding cognitive status after traumatic bra in injury (TBI). A database containing 319 TBI patients with a broad spectr um of coma duration was used. Statistical analysis of mixed effects modelli ng was applied to longitudinal WAIS-R (Wechsler Adult Intelligence Scale-Re vised) scores to construct two mathematical models (verbal IQ and performan ce IQ). The models predict the course of recovery (initial cognitive level post-coma, eventual recovery level, and level of cognitive functioning at a ny point on the recovery curve) when the duration of coma is known. Perform ance IQ was found to recover at a rate that is almost four times slower tha n verbal IQ. The results have important clinical rehabilitation implication s. This statistical modelling technique also enables the medical researcher to investigate disease progression or recovery using structured assessment s, which would normally be part of the routine medical monitoring.