Behcet's disease (BD) is a multisystem inflammatory disorder characterized by recurrent oral and genital ulcers and uveitis. BD patients without neurological involvement frequently have mild neurological symptoms. The aim of this study was to evaluate whether BD patients without neurological involvement have any changes in cognitive functions. Twenty BD patients without neurological involvement and 13 control subjects were included in the study and were analyzed by neurophysiological and neuropsychological examinations. The cognitive event- related potentials (P300) were recorded from the frontal, central and parietal areas of the right and left hemispheres of the patients and control subjects. Likewise, all individuals were evaluated with neuropsychological tests. In contrast to a study with similar design, C, we did not find any difference between the cognitive event-related potentials values of BD patients without neurological involvement and the control subjects. All BD patients without neurological involvement exhibit normal results of the neuropsychological test. In conclusion. the results of neuropsychological tests and cognitive event-related potentials values in BD patients without neurological involvement are indistinguishable from those in control subjects and no alteration of cognitive functions is present. (c) 2005 Tohoku University Medical Press.