A Prospective Investigation of Long-Term Cognitive Impairment and Psychological Distress in Moderately Versus Severely Injured Trauma Intensive Care Unit Survivors Without Intracranial Hemorrhage

BACKGROUND: The primary objective was to prospectively determine the 12-month prevalence of cognitive impairment and psychologic difficulties in moderately versus severely injured adult trauma intensive care unit (TICU) survivors without intracranial hemorrhage. METHODS: We conducted a prospective cohort study in which patients were followed for 1 year after hospital discharge. A total of 173 patients from the Vanderbilt TICU who had an Injury Severity Score (ISS) of >15 (indicative of moderately severe trauma) were enrolled between July 2006 and June 2007. Patients were screened for delirium on a daily basis in the TICU by study personnel via the confusion assessment method of the ICU, and preexisting cognitive impairment was assessed through a surrogate-based evaluation using the short form of the Informant Questionnaire for Cognitive Decline in the Elderly. Of these patients, 108 were evaluated 1 year after hospital discharge with a comprehensive battery of neuropsychological tests and depression and posttraumatic stress disorder (PTSD) instruments. Cognitive impairment was defined as having two neuropsychological test scores 1.5 SD below the mean or one neuropsychological test score 2 SD below the mean. RESULTS: Fifty-nine patients (55%) demonstrated cognitive impairment at 12-month follow-up, with three of these patients (5.5%) having preexisting impairment. Clinically significant symptoms of depression and PTSD occurred in 40% and 26% of patients, respectively. No significant differences in cognitive impairment (59% vs. 50%), depressive symptoms (35% vs. 44%), and symptoms of PTSD (22% vs. 28%) were identified between moderately (ISS 15-25) and severely (ISS>25) injured TICU survivors, respectively (all p>0.05). In addition, multivariate logistic regression analysis found that moderately injured trauma patients had a similar rate of cognitive impairment when compared with those with severe injury at 12-month follow-up (p=0.25). CONCLUSION: Long-term cognitive impairment is highly prevalent in TICU survivors without intracranial hemorrhage as are psychologic difficulties. Injury severity, concussion status, and delirium duration were not risk factors for the development of neuropsychological deficits in this cohort. Individuals with moderately severe injuries seem to be as likely as their more severely injured counterparts to experience marked cognitive impairment and psychologic difficulties; thus, screening efforts should focus on this potentially overlooked patient group.