Vestibular dysfunction in Gulf War syndrome.
METHODS
Vestibular complaints of Gulf War veterans were characterized by a nested case-control study of 23 veterans with 3 different Gulf War syndromes and 20 matched control subjects. All subjects completed a standardized symptom questionnaire and underwent standard audiovestibular tests administered by audiologists blinded to group identities.


RESULTS
The prevalence of reported dizzy spells was higher in veterans with Gulf War syndromes 1 (100%), 2 (85%), and 3 (100%) than in controls (25%, P < 0.0001). Dizzy spells were more frequent, lasted longer, and involved a wider variety of accompanying symptoms in veterans with syndrome 2 than in those with syndromes 1 and 3. Audiovestibular testing showed greater interocular asymmetry of nystagmic velocity on sinusoidal harmonic acceleration in syndromes 1 (P = 0.015) and 2 (P = 0.002), greater asymmetry of saccadic velocity in syndrome 2 (P = 0.4), diminished nystagmic velocity after caloric stimulation bilaterally in syndrome 3 (P = 0.02 to 0.04), more subjects with pathologic nystagmus (P = 0. 09), and greater interside asymmetry of wave I to III interpeak latency on auditory brain stem response in syndromes 1 (P = 0.005) and 2 (P = 0.07). Asymmetry of gain on sinusoidal harmonic acceleration and pathologic nystagmus were most strongly associated with symptoms of paroxysmal vertigo (P = 0.002 and 0.07, respectively); asymmetry of saccadic velocity, with the severity of vertigo (P = 0.004); and abnormal caloric response, with chronic dysequilibrium (P = 0.006).


CONCLUSIONS
The findings are compatible with a subtle neurologic injury from organophosphate-induced delayed neurotoxicity.
Roland
P S
PS
Department of Otolaryngology and the Epidemiology Division, University of Texas Southwestern Medical Center, Texas, USA.
Haley
R W
RW
Yellin
W
W
Owens
K
K
Shoup
A G
AG
D000328:Adult; D001300:Audiometry, Evoked Response; D001933:Brain Stem / Q000503:physiopathology; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004292:Dominance, Cerebral / Q000502:physiology; D004584:Electronystagmography; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D006801:Humans; D015994:Incidence; D008297:Male; D008575:Meniere Disease / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D008875:Middle Aged; D018923:Persian Gulf Syndrome / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D015837:Vestibular Diseases / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D014724:Vestibular Function Tests; D014722:Vestibule, Labyrinth / Q000503:physiopathology