Symptom Domain Predictors of Auditory Processing Anomalies in Posttraumatic Stress Disorder: An Event-related...

Posttraumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI) commonly co-occur and are associated with deficits in auditory processing and attention. To better understand the underpinnings of deficits in directed auditory attention, we examined whether individual PTSD symptom domains or mTBI severity were associated with distinct anomalies during early, middle, and late neural responses to auditory stimuli.

The Clinician Administered PTSD Scale (CAPS-IV) and Minnesota Blast Exposure Screening Tool were used to evaluate symptoms of previously deployed U.S. combat Veterans (N = 128). Linear mixed effects models were used to test whether PTSD symptom severity and mTBI blast injury severity were associated with atypical N1, Midlatency, and P300 event-related potentials during a directed attention oddball task.

Greater Avoidance symptomatology was associated with larger N1 amplitude, suggesting increased reflexive, sensory attention allocation. Greater Dysphoria symptomatology was associated with smaller Midlatency amplitude, relevant to novelty and target detection. Greater Hyperarousal symptomatology was associated with smaller P300 amplitudes for rare, attended target stimuli, indicating blunted responsiveness to behaviorally relevant stimuli. There was no significant main effect of mTBI blast severity on neural responses or task performance and few effects related to categorical diagnoses of PTSD and mTBI.

Atypical neural responses during the directed auditory attention oddball task are predicted primarily by PTSD symptomatology, not mTBI blast severity. Avoidance is tied to exaggerated early reflexive responses, dysphoria is related to muted novelty detection, and hyperarousal is associated with difficulty distinguishing between stimuli relevant and irrelevant to behavior.