B-68 Resistance to Distraction and Working Memory Function: Electrophysiological Attentional Markers and Digit Span Performance

Abstract Objective Working memory (WM) function requires attentional focus and resisting distracting stimuli (i.e., resistance to attentional capture [RAC]). People with histories of mild traumatic brain injury (mTBI) or posttraumatic stress (PTSD) often report difficulties with WM and attention. To better understand the relationship between these two executive functions, we collected neuropsychological and electrophysiological data from a sample of individuals with PTSD and/or mTBI. Methods We characterized WM function in 128 US military veterans (61 controls, 22 PTSD, 24 mTBI, 21 PTSD and mTBI) using the WAIS-IV Digit Span (DS). To examine RAC we completed electroencephalography recordings during an Erikson Flanker task. Flanker task trials were coded as either Congruent (flanker stimuli same direction as target) or Incongruent (opposite direction). We characterized the P1 event-related potential which has shown sensitivity to RAC. Results There was an interaction between Flanker Type and DS such that poorer WM performance was related to greater difficulties on Incongruent trials. Analyses of P1 amplitude revealed an interaction between DS scores and P1 amplitude with better DS performance related to larger P1 amplitudes in trials with Incongruent compared to Congruent flankers. There was also an interaction between PTSD and Flanker Type such that PTSD was associated with larger P1 amplitudes for Incongruent than Congruent flanker trials. Conclusions Our observations suggest greater RAC aids in WM function, and is also associated with early perception-related brain responses (i.e., P1) that modulate with demands to resist distracting stimuli. Our results also suggest PTSD is related to electrophysiological functions tied to RAC.