CLASSIFICATION OF VETERANS WITH POSTTRAUMATIC-STRESS-DISORDER USING VISUAL BRAIN EVOKED P3S TO TRAUMATIC STIMULI

Background. Post-traumatic stress disorder (PTSD) typically involves a re-experiencing of traumatic events. in a previous P3 study it was fo und that PTSD patients react both selectively and involuntarily to com bat-related pictures, exhibiting augmented P3 event-related potentials and thus providing a brain activity measure. The clinical application of these findings in differentiating PTSD patients from controls was tested. Method. Twenty Israeli combat veterans suffering from PTSD and 20 age-matched veterans without PTSD were evaluated. P3 potentials we re recorded at Pz and Cz in response to visual motor-task target stimu li (pictures of domestic animals), non-target probe stimuli (combat-re lated pictures), and non-target irrelevant stimuli (pictures of furnis hings and flowers). Results. Using the Fisher Linear Discrimination Me thod the P3 measures correctly classified 90% of the PTSD patients and 85% of the controls. Conclusions. Visual P3s recorded in response to combat-related pictorial stimuli may introduce an efficient tool for s tudying higher brain activity in PTSD, complementing other behavioural and psychophysiological measurements.