A-128 Intraindividual Neurocognitive Variability Is Associated with Poorer Prospective Memory in OEF/OIF/OND Veterans with Comorbid Mild Traumatic Brain Injury History and Current Posttraumatic Stress Disorder

Objective Mild Traumatic Brain Injury (mTBI) and Posttraumatic Stress Disorder (PTSD) frequently co-occur in service members, and each are associated with increased neurocognitive intraindividual variability (IIV), a proposed indicator of subtle disruptions in executive control, and prospective memory (PM), or “remembering to remember.” The current study sought to examine possible associations between IIV and PM performances among Veterans with comorbid mTBI and PTSD. Methods 46 OEF/OIF/OND Veterans with a history of mTBI and current PTSD enrolled in a VA research study of mTBI completed a standardized neurocognitive battery of 12 measures used to calculate the coefficient of variation (CoV) as an index of IIV, and the Memory for Intentions Screening Test (MIST) as a measure of PM. Veterans also completed clinical questionnaires (i.e., Patient Health Questionnaire-9, PTSD Checklist-Military), and a subset of the sample (n = 31) Veterans completed the Prospective and Retrospective Memory Questionnaire (PRMQ) as a measure of self-reported PM. Results Controlling for age and education, higher CoV was associated with time-based MIST scores (β = −0.02, p = 0.008, η2 = 0.16) and event-based MIST scores (β = −0.02, p = 0.031, η2 = 0.11). CoV was not associated with mood factors in the sample (ps >0.10). In a subset of the total sample, higher CoV was associated with elevated self-reported PM symptoms (r = −0.36, p = 0.046). Conclusions Among Veterans with a history of mTBI and current PTSD, elevated variability of performances across neurocognitive measures was associated with poorer performance-based PM and self-reported PM symptoms. Future studies are needed to examine IIV as a predictor of real-world PM performances (e.g., medication adherence).