title: Posttraumatic stress disorder is associated with limited executive resources in a working memory task.
abstract: Patients with posttraumatic stress disorder (PTSD) can show declines in working memory. A dual-task design was used to determine whether these impairments are linked to executive control limitations. Participants performed a Sternberg memory task with either one or four letters. In the dual-task condition, the maintenance period was filled with an arrow flanker task. PTSD patients were less accurate on the working memory task than were controls, especially in the dual-task condition. In the single-task condition, both groups showed similar patterns of brain potentials from 300 to 500 ms when discriminating old and new probes. However, when taxed with an additional task, the event-related potentials (ERPs) of the PTSD group no longer differentiated old and new probes. In contrast, interference resolution processes in both the single- and dual-task conditions of the flanker task were intact. The lack of differentiation in the ERPs reflects impaired working memory performance under more difficult, dual-task conditions. Exacerbated difficulty in performing a working memory task with concurrent task demands suggests a specific limitation in executive control resources in PTSD.
authors.affiliation: Medical Research Service, VA Northern California Health Care System, 150 Muir Road, Ste. 151-I, Martinez, CA, USA, nhonzel@gmail.com.
authors.forename: Nikki
authors.initials: N
authors.lastname: Honzel
authors.forename: Timothy
authors.initials: T
authors.lastname: Justus
authors.forename: Diane
authors.initials: D
authors.lastname: Swick
mesh_terms: D000328:Adult; D055826:Afghan Campaign 2001-; D001244:Association; D001931:Brain Mapping; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D054542:Iraq War, 2003-2011; D008297:Male; D008569:Memory Disorders / Q000209:etiology*; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D013313:Stress Disorders, Post-Traumatic / Q000150:complications*; D014728:Veterans; D055815:Young Adult