P50 suppression, prepulse inhibition, and startle reactivity in the same patient cohort suffering from posttraumatic stress disorder

Background: Psychophysiological alterations like impaired gating and increased startle have been reported in patients with posttraumatic stress disorder (PTSD). However, findings are inconsistent, and potential relationships to symptomatology remain unclear. Aims: The present study investigates two distinct operational measures of gating and startle reactivity within the same patients suffering from PTSD and their relationship to PTSD symptomatology. Methods: Prepulse inhibition of the acoustic evoked startle reflex, P50 suppression of auditory event related potentials, and startle reactivity were assessed in three distinct experiments in 27 PTSD patients and compared to 25 healthy control subjects. Results: PTSD patients exhibited impaired P50 suppression and exaggerated startle. Lower P50 suppression was associated with higher levels of general psychopathology. Patients and control subjects did not differ in PPI. Limitations: Some of the limitations include, that the control group compromised of non-trauma exposure subjects and menstrual cycle in female participants potentially affecting PPI was not controlled. Conclusions: Deficient P50 gating, not related to specific trauma or distinct symptom clusters reflects a robust finding in PTSD patients. In contrast, further research is needed to clarify whether PPI is affected in PTSD. (C) 2010 Elsevier B.V. All rights reserved.