EEG features of the apallic syndrome resulting from cerebral anoxia

Three victims of severe cerebral anoxia developed the apallic syndrome, and clinical neurophysiological examinations documented slow evolution of a diurnal behavior pattern. Marked EEG attenuation was the primary finding, but all the patients exhibited clustering of quiescent periods at night, during which EEG waves were generated, and two stages suggested REM and non-REM sleep. The results seemed to confirm the notions that brain-stem mechanisms control occurrence of REM and non-REM sleep, and that forebrain mechanisms are required for development of differential EEG features of non-REM sleep stages (I through IV). It is also suggested that an extreme degree of attenuation resulting from EEG desynchronization in certain patients may closely resemble ECS.