In a series of 80 diffuse brain injuries with early clinical signs of brainstem dysfunction without shift of the midline on the first CT SCAN investigation; the authors have studied the time course of recovery. Among several neurological parameters, they have choosen two steps: first one the spontaneous opening of the eyes, which marks a restoration of vigilance, second one the capacity to execute simple commands which marks the end of unconsciousness). The duration of the period of recovery (delta) (between the eyes opening and the obays commands) was variable from 0 to 173 days. But it was a good statistic correlation (p less than 0,001) between the length of this period and the functional outcome at one year.