Correlations between Cognitive Impairments and Employment Status in Patients with Diffuse Axonal Injury

Patients with diffuse axonal injury (DAI) may initially present with prominent physical impairments, but their cognitive dysfunctions are more persistent and are attributable to later unemployment. In this study, we analyzed how the findings of early and delayed neuropsychological assessments correlated with employment outcome of patients with DAI. A total of 56 patients with DAI without motor or visual dysfunction were included in this study. The neuropsychological battery consisted of the Wechsler Adult Intelligent Scale - Revised (WAIS-R), Wechsler Memory Scale - Revised (WMS-R), Trail Making Test (TMT), Wisconsin Card Sorting Test (WCST), and Word Fluency Test (WFT). This battery of tests was administered twice in early stage after injury and in later stage. The results of all of the neuropsychological tests improved significantly (P <0.001) between the early and later assessments. All scores other than TMT part A and B improved to the normal range (Z-score ≥ 2). The patient characteristics (age, gender, initial Glasgow Coma Scale, and duration of posttraumatic amnesia) had no relationship to the outcome. The results of TMT part B, however, were significantly correlated with employment outcome in both the early and later assessments (P = 0.01, 0.04). Given that TMT evaluates visual attention, we surmise that a lack of attention may be the core symptom of the cognitive deficit and cause the re-employment failure in patients with DAI. TMT part B in both early and later assessments has the potential to accurately predict chronic functional outcome.