Event-related potentials to stimuli with emotional impact in posttraumatic stress patients

Psychophysiological research has given conflicting results with respect to whether the abnormal physiologic responses observed in posttraumatic stress disorder (PTSD) reflect a general abnormality or are linked to trauma-related stimuli. We studied differences in the central nervous processing of words with emotional impact in survivors after a ship fire disaster.

Event-related potentials were studied in 11 survivors with posttraumatic stress pathology, and compared with 9 survivors without such pathology. Nonwords and words with negative or positive emotional valence were used as distractors in a P3 oddball paradigm.

PTSD subjects had increased N1 latency to standard tones and increased positive amplitude to both words and nonwords compared with controls, occurring between 200 and 350 msec after stimulus onset. The amplitudes to emotionally meaningful words were significantly related to Clinician-Administered PTSD Scale-assessed PTSD dimensions, in particular avoidance and arousal.

The abnormality in information processing observed in PTSD patients seems in part to be linked with increased attention, in part with emotional responses to the trauma. Intrusion was mainly related to the processing of nonwords, while arousal and avoidance were related to event-related potential amplitudes to emotionally meaningful words, suggesting that intrusion has a different neurobiological basis than arousal and avoidance.