Frontal spindle activity that appears in conjunction with nontraumatic diffuse encephalopathy.

Abstract

This peculiar 11-14 Hz spindle activity appears predominantly in the frontal area, and was observed in eight patients with impaired consciousness caused by nontraumatic diffuse encephalopathy. Characteristic of this frontal spindle activity is its transience and accordance with changes in the arousal level of the patient. When the degree of impaired consciousness in the patient was minimal and clinically not very apparent, this spindle activity appeared during light drowsiness. In lethargic patients, it was observed when the patient's level of consciousness rose (e.g. immediately after opening and closing the eyes). These frontal spindles disappeared at the onset of Stage 2 sleep, when normal physiologic spindle waves that are dominant in the vertex area appeared. A paroxysmal discharge was sometimes recorded in association with the frontal spindle activity and it disappeared at about the same time as these spindles. The prognosis was satisfactory for all patients in whom frontal spindle activity was observed; its correlation to spindle coma is also studied.