PHYSIOLOGICAL-RESPONSES TO LOUD TONES IN VIETNAM VETERANS WITH POSTTRAUMATIC-STRESS-DISORDER

The authors evaluated eyeblink and autonomic components of the acousti c startle response in combat-related posttraumatic stress disorder (PT SD). Thirty-seven Vietnam combat veterans with current PTSD and 19 com bat veterans without PTSD were exposed to 15 consecutive 95-dB, 500-ms , 1000-Hz tones with 0-ms rise and fall times, while orbicularis oculi electromyogram, skin conductance, and heart rate responses were measu red. PTSD veterans produced larger averaged electromyographic and hear t rate responses, and a slower decline in skin conductance responses, across the 15 tone presentations compared to non-PTSD veterans. Result s of this study provide laboratory support for an exaggerated startle response in PTSD and replicate and extend previous findings of increas ed autonomic responses to loud tone stimuli in this disorder.