Physiologic responses to loud tones in Israeli veterans of the 1973 Yom Kippur War.

Eyeblink and autonomic components of the acoustic startle response were evaluated in a community sample of Israeli veterans of the Yom Kippur war. Individuals were solicited by mail and telephone to participate in the study; they were not seeking treatment or compensation. Nineteen Israeli veterans with current posttraumatic stress disorder (PTSD) and 74 veterans without PTSD were exposed to 15 consecutive 95-dB, 500-msec, 1000-Hz tones with 0-msec rise and fall times, while orbicularis oculi electromyogram, skin conductance, and heart rate responses were measured. Individuals with PTSD produced larger averaged heart rate responses, and a slower decline in skin conductance responses, across the 15 tone presentations compared to non-PTSD subjects. There was no group difference in the magnitude of the averaged electromyogram response. Results of this study replicate previous findings of increased autonomic responses to loud tone stimuli in this disorder.