title: EEG topography of response to visual stimuli in generalized anxiety disorder.
abstract: EEG activity was recorded in 11 normal subjects and 19 patients with generalized anxiety disorder (GAD) at rest and while they were viewing a series of ten 4 sec continuous lights. Topographical cortical changes were assessed using 32-channel EEG power estimate maps. The percent changes from baseline to stimulation, for the first 5 and the last 5 light stimuli, were calculated and topographically mapped. Patients with GAD showed less decrease in alpha activity during the first 5 stimuli and more alpha activity during the last 5 stimuli in comparison to normal controls. Delta, theta, alpha, beta I and beta II did not show any difference during the resting periods. The topographical distribution of response to light was different in each group. Normal controls had a parieto-occipital reactivity and GAD patients a centro-parietal one with the maximum difference between the two groups being located in the occipital region. During the stimulation, beta I activity was decreased in controls and increased in patients. The diminishing reactivity of the patients is interpreted as a diminution of attention to external stimulation because of competing internal interferences. The pattern of regional reactivity suggests the importance of the centro-parietal and/or occipital regions in anxiety.
mesh_terms: D000328:Adult; D000513:Alpha Rhythm; D001008:Anxiety Disorders / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D009949:Orientation / Q000502:physiology*; D010775:Photic Stimulation