Primary objective: A modified Stroop task was used to investigate the hypothesis that implicit memory may be a possible mechanism for the development of acute stress disorder (ASD) in patients who have suffered a closed head injury.
Research design: Three groups of hospital patients were compared within 1 month post-trauma: road traffic accident (RTA) patients with a brain injury (n = 15), RTA patients without a brain injury (n = 13) and a control group of orthopaedic and plastics patients (n = 15).
Methods and procedures: Participants named colours of five types of words: RTA-related words, words related to hospitalization, obsessive-compulsive disorder (OCD) words, positive words and neutral words. Participants were also administered the Acute Stress Disorder Interview and the State-Trait Anxiety Inventory.
Main outcomes and results: Both RTA patients with and without a brain injury demonstrated significant interference on words related to an RTA. Significant interference was unexpectedly observed for OCD words in RTA patients. Control patients did not display significant interference effects.
Conclusions: Findings suggested that patients, both with and without explicit recall for an RTA, responded similarly on a task involving implicit memory for trauma. Possible implications for ASD and Post-traumatic Stress Disorder are discussed.