Short-term memory in Croatian war veterans with posttraumatic stress disorder

Aim

To assess short-term memory impairment in war veterans with combat-related posttraumatic stress disorder (PTSD).

Method

The study included 20 war veterans diagnosed with PTSD and 21 control subjects matched for age, sex, and education level. Both groups were tested with the Rey-Osterrieth Complex Figure Test (ROCFT), consisting of Copy, Immediate Recall, and Delayed Recall steps, and Benton Visual Retention Test (BVRT). Subjects with visuoperceptive and visuoconstructional deficits, as indicated by their ROCFT Copy scores were excluded from the analysis, because this type of cognitive deficit could interfere with the results of the next two ROCFT steps measuring short-term memory.

Results

Subjects with PTSD scored significantly lower than control subjects on both Immediate Recall (mean ± standard deviation [SD], 16.3 ± 6.4 vs 26.7 ± 4.5, respectively; P<0.001, t test for independent samples) and Delayed Recall tests (15.7 ± 6.1 vs 26.3 ± 4.6, respectively; P<0.001, t test for independent samples) on ROCFT test. Intragroup comparison showed that both groups scored significantly lower on Immediate Recall test in comparison with Copy test (19.3 ± 6.4 for veterans and 8.9 ± 4.5 for controls; P<0.001 for both, t test for dependent samples), whereas no significant score difference was found between Immediate and Delayed Recall scores in either group (0.7 ± 2.4 for veterans, P = 0.239, t test for dependent samples; and 0.5 ± 1.8 for controls, P = 0.248, t test for dependent samples), which indicated greater difficulties with acquiring new information than with recalling already memorized information. Subjects with PTSD made significantly more errors on the BVRT for visuoperceptive and visuoconstructional abilities than control subjects (7.8 ± 2.9 for veterans; 4.0 ± 1.88 for controls; P<0.001, t test for independent samples).

Conclusion

War veterans with PTSD had impaired short-term memory and visual retention, but these cognitive deficits could not be related to traumatic experiences with certainty.Chronic posttraumatic stress disorder (PTSD) is accompanied with pathophysiological and biological changes in the brain structures such as hippocampus, amygdale, cortex, nucleus accumbens, striatum, and midbrain (1). These changes may be caused by traumatic experience and responsible for the appearance of PTSD symptoms (1). According to the modern concept of PTSD, it is a psychobiological phenomenon that includes neurobiological dysregulation and psychological dysfunction (2). Studies using sophisticated methods for brain imaging found the dysfunction of the frontal-limbic system as the biological correlate of PTSD (3). Magnetic resonance imaging studies showed that in chronic PTSD patients the volume of the hippocampus was reduced, which affects the learning and memory processes (3-5). The hippocampus atrophy is suspected to result from oversensitivity of the glucocorticoid receptors and increased concentration of glucocorticoids in persons exposed to stress (3,5). However, these changes in hippocampus are not caused by the traumatic experience alone. The trauma is constantly reexperienced through flashbacks and dreams, which are characteristic elements of the clinical picture of PTSD (3). In many PTSD patients, other cognitive dysfunctions are also present, such as intellectual deterioration (3,6), impaired executive functions (3), decreased concentration (7-9), memory deficits (7-9), and forgetfulness (9,10).Due to the high prevalence of PTSD among veterans from 1991-1995 war in Croatia, the degree of PTSD symptoms in this population is frequently assessed (11). Improving our knowledge about memory deficits in PTSD patients would facilitate the severity assessment of the disorder for the purposes of work fitness evaluations and therapy planning (12,13).The aim of this study was to determine the short-term memory deficit in Croatian war veterans with PTSD by comparing their immediate and delayed recall and visual retention abilities with those of healthy controls.