[Neurologic characteristics of patients with flat EEG's and EEG's with predominant low-frequency beta activity]

The authors analyzed clinical manifestations and reactive changes in the EEG in response to eye opening and light flickering in 3 groups of patients selected according to the parameters of baseline EEGs: Group I (control) (n = 20) was characterised by normal EEG; Group II (n = 50) by domination in the EEG of beta-activity of low frequency; Group III (49 patients) by a "flat" curve. It was found that micro-symptoms of organic lesion of the CNS were observed in 15% of the Group I patients, in 36% of the Group II patients, and in 61.2% of Group III patients. In Group II neurotic and neurosis-like manifestations of a hysterical type were observed in 34% of the patients while 38% of the patients in Group III presented anxiety-depressive states. The groups studied also showed significant differences in reactive shifts in the EEG. A scheme of identification of different EEG-syndrome complexes may prove useful in clinical electroencephalography.