Sensory gating in chronic posttraumatic stress disorder: reduced auditory P50 suppression in combat veterans

Biol Psychiatry. 1999 Dec 15;46(12):1656-64. doi: 10.1016/s0006-3223(99)00047-5.


Background: Posttraumatic stress disorder (PTSD) may be associated with a general impairment of cognitive function that extends beyond the processing of trauma-specific stimuli. Suppression of the auditory P50 response to repeated stimuli occurs in normal subjects and reflects the central nervous system's ability to screen out repetitive stimuli, a phenomenon referred to as sensory gating. This study examines P50 sensory gating to nonstartle auditory stimuli in PTSD subjects and normal controls.

Methods: P50 generation and gating were studied using a conditioning/testing paradigm in 15 male subjects with PTSD and 12 male controls. P50 test/conditioning (T/C) ratios were estimated using the Singular Value Decomposition method.

Results: The amplitude of the P50 response to the conditioning stimulus did not differ in subjects with PTSD compared to normal controls. The P50 T/C ratio is increased in PTSD subjects (mean = .408, SD = .275) as compared to the controls (mean = .213, SD = .126, two tailed t, p = .024).

Conclusions: This study provides evidence that PTSD is associated with impaired gating to nonstartle trauma-neutral auditory stimuli.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Auditory Threshold*
  • Brain / physiopathology*
  • Case-Control Studies
  • Electroencephalography
  • Evoked Potentials, Auditory*
  • Habituation, Psychophysiologic*
  • Humans
  • Male
  • Middle Aged
  • Neural Inhibition
  • Stress Disorders, Post-Traumatic / physiopathology*
  • United States
  • Veterans* / statistics & numerical data
  • Vietnam
  • Warfare