Patients with posttraumatic stress disorder show decreased cognitive control: evidence from dichotic listening.

The influence of posttraumatic stress disorder (PTSD) on cognitive control and auditory attention modulation was examined with the use of a dichotic-listening (DL) task. The participants were 45 war-exposed refugees. The PTSD group comprised 22 participants meeting the DSM-IV criteria for PTSD, and the Control group comprised 23 war-exposed participants without PTSD. Both groups were tested with a consonant-vowel syllables DL task under three different attentional instructions. The two groups did not differ in the non-forced and forced-right conditions and showed, as expected, right-ear advantages. The Control group showed, as expected, a left-ear advantage in the forced-left (FL) condition. However, the PTSD group continued to show a right-ear advantage--and only minor modulation of the performance during the FL condition. This finding suggests that PTSD is associated with a reduced capacity for top-down attentional control of a bottom-up or stimulus-driven effect. The result shows that participants with PTSD have impaired cognitive control functions when tested on information processing of neutral stimuli.