Absence of Quantitative Improvement in Neuropsychological Profiles in Patients Who Exhibit Moderate Brain Impairment: Comparisons of Cross-Sectional and Longitudinal Data (1 through 4 Years Post-Injury)

Abstract

A total of 127 adult patients who had sustained an impact of significant mechanical energy to their skulls during motor vehicle incidents were given thorough neuropsychological, cognitive and personality assessments between 0.5 years and 4 years after the event. Cross-sectional analysis indicated no statistically significant objective changes in patients as a function of yearly intervals. However there was strong evidence of significant deterioration of neuropsychological proficiency and efficiency between 0.3 to 1.0 years after the injury. A subset (n = 20) of patients who displayed moderately severe neuropsychological impairment when assessed about 1 year after the injury showed no statistically significant changes when reassessed about 1.5 years later (2.5 years after the brain trauma). These results challenge the traditional concept of “recovery” following a traumatic brain injury and indicate that insidious processes that adversely affect neurocognitive capacity may emerge 0.5 years after the trauma. Post-hoc analysis indicated that the occurrence of unconsciousness or its duration at the time of the injury minimally affected the magnitude of subsequent indices of neuropsychological impairment but influenced the incidence of electroencephalographic theta activity during the years following the injury.