Meta-analysis of execution functions in patients with post-traumatic stress disorder

Abstract

Objective To take a system review on the impairment of executive functions in patients with post-traumatic stress disorder (PTSD). Methods A meta-analysis was performed to summarize the literature on the executive functions in patients with PTSD, healthy controls and trauma-exposed controls without any psychiatric disorder. Trial Making Test B (TMT B), Wisconsin Card Sorting Test, WCST), Stroop test, Rey-Osterrieth Complex Figure Test (ROCFT) copy, Wechsler Adult Intelligence Scale Revised/Wechsler Memory Scale digit span were chosen to as the indices of executive functions. The databases of Pubmed, EMBase and Web of Knowledge were searched from January 1985 and October 2014. The key words PTSD or posttraumatic stress disorder and neurocognit* or neuropsychology* or cognitive impairment orexecutive function or working memory were used. The literature search was conducted according to the inclusive and exclusive criteria. Original research were published between January 1985 and October 2014, and selected according to the inclusion criteria and exclusion criteria. Revman 5.3 software was used for statistical analysis. Results A total of 35 primary studies were identified, including 1 218 PTSD patients, 2 570 trauma-exposed controls and 683 healthy controls. The performance of TMT B in PTSD group were statistically significant worse than that in the trauma-exposed control group (standardized mean difference, SMD:0.63, 95%CI:0.35-0.91, P=0.00). Furthermore, PTSD group showed significant worse performance on TMT B (SMD:0.49, 95%CI:0.07-0.90, P=0.02), WCST categories completed (SMD:-0.39, 95%CI:-0.74-0.05, P=0.02), ROCFT copy (SMD:-0.43, 95%CI:-0.76-0.09, P=0.01), Wechsler Adult Intelligence Scale Revised/Wechsler Memory Scale digit span scores (Digit span forward: SMD:-0.28, 95%CI:-0.52-0.03, P=0.03; Digit span backward: SMD:-0.32, 95%CI:-0.63-0.00, P=0.05; Digit span total: SMD:-0.49, 95%CI:-0.85-0.13, P=0.01) were lower than healthy control group. No significant difference were found between PTSD and trauma-control group in WCST perseverative errors, WCST categories completed, Stroop test, ROCFT copy and Digit span (including Digit span forward, Digit span backward and Digit span total). The scores of WCST perseverative errors, Stroop test in PTSD group showed no significant difference with those in the healthy control group. The scores of TMT B, Digit span forward, Digit span backward in the trauma-exposed control group showed no significant difference with those in the healthy control group. Conclusions These data support the impaired executive functions of patients with PTSD, which may partially attribute to trauma exposure. Key words: Post-traumatic stress disorder; Executive functions; Meta-analysis