EVENT-RELATED POTENTIALS IN POSTTRAUMATIC-STRESS-DISORDER OF COMBAT ORIGIN

Visual event-related potentials (ERPs) of primary interest in this stu dy of post-traumatic stress disorder (PTSD) were N1, N2, P2, and P3, F orty Israeli combat veterans consisting of 20 PTSD sufferers and 20 no rmal controls were evaluated. ERPs were recorded in response to three sets of computer-generated visual stimuli, presented in the form of a modified oddball paradigm. These stimuli included: domestic animal pic tures (targets), emotionally neutral pictures of furnishings (nontarge ts), and combat-related pictures (nontarget probes), Subjects were req uired to discriminate between target and nontarget stimuli by pressing a button in response to target stimuli only. Subjects were instructed to ignore all nontarget stimuli. As expected, target stimuli evoked a ccentuated P3 amplitudes in both controls and PTSD patients. The nonta rget combat-related pictures elicited enhanced P3 and NI amplitudes in the PTSD patients only. N2 amplitudes were accentuated in PTSD patien ts for both targets and combat-related pictures. P3 latencies and reac tion times to target stimuli were prolonged in PTSD patients. The same tendency was observed for N1 latencies, These results may indicate th at an altered state of early and late cognitive selective attention pr ocessing exists in PTSD patients in addition to a vulnerability to tra umatic reminiscences.