We analyzed EEGs performed over a 8-month period on patients with impa
ired consciousness following acute hypoxia or anoxia. There were 17 EE
Gs performed on 14 patients. Nine of the 17 records contained spindle
activity. Spindles were present in 6/8 EEGs in stuporous patients, in
3/9 EEGs in comatose patients, in 6/10 patients who eventually died, a
nd in 3/3 patients who regained consciousness. When spindle activity o
r background reactivity were absent, outcome was poor, ie, death or a
persistent vegetative state. The presence of EEG spindle activity afte
r hypoxic or anoxic injury did not indicate a favorable prognosis, but
the absence of spindles or EEG background reactivity was associated w
ith a poor outcome.