title: Visual event-related potentials as markers of hyperarousal in Gulf War illness: evidence against a stress-related etiology.
abstract: An exaggerated response to emotional stimuli is among the many symptoms widely reported by veterans of the 1991 Persian Gulf War. These symptomologies have been attributed to damage and dysfunction associated with deployment-related exposures. We collected event-related potential data from 22 veterans meeting Haley criteria for Gulf War (GW) Syndromes 1-3 and from 8 matched GW veteran controls, who were deployed but not symptomatic, while they performed a visual three-condition oddball task where images authenticated to be associated with the 1991 Persian Gulf War were the distractor stimuli. Hyperarousal reported by ill veterans was significantly greater than that by control veterans, but this was not paralleled by higher amplitude P3a in their ERP responses to GW-related distractor stimuli. Whereas previous studies of PTSD patients have shown higher amplitude P3b responses to target stimuli that are placed amid trauma-related nontarget stimuli, ill veterans in this study showed P3b amplitudes to target stimuli - placed amid GW-related nontarget stimuli - that were significantly lower than those of the control group. Hyperarousal scores reliably predicted P3b, but not P3a, amplitudes. Although many factors may contribute to P3b amplitude differences - most notably depression and poor sleep quality, symptoms that are prevalent in the GW syndrome groups - our findings in context of previous studies on this population are consistent with the contention that dysfunction in cholinergic and dopaminergic neurotransmitter systems, and in white matter and basal ganglia may be contributing to impairments in GW veterans.
authors.affiliation: Center for BrainHealth, The University of Texas at Dallas, USA.
authors.forename: Gail D
authors.initials: GD
authors.lastname: Tillman
authors.forename: Clifford S
authors.initials: CS
authors.lastname: Calley
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Green
authors.forename: Virginia I
authors.initials: VI
authors.lastname: Buhl
authors.forename: Melanie M
authors.initials: MM
authors.lastname: Biggs
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Spence
authors.forename: Richard W
authors.initials: RW
authors.lastname: Briggs
authors.forename: Robert W
authors.initials: RW
authors.lastname: Haley
authors.forename: Michael A
authors.initials: MA
authors.lastname: Kraut
authors.forename: John
authors.initials: J
authors.lastname: Hart
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001931:Brain Mapping; D016022:Case-Control Studies; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018923:Persian Gulf Syndrome / Q000150:complications*; D010775:Photic Stimulation; D011595:Psychomotor Agitation / Q000175:diagnosis* / Q000209:etiology*; D011930:Reaction Time / Q000502:physiology; D012720:Severity of Illness Index; D014728:Veterans