[Diagnostic and prognostic value of the brain stem reflexes in severe post-traumatic coma]

Authors study the neurological evolution of 50 cases of traumatic coma and recognize 5 misfunction levels corresponding to five steps of rostrocaudal deterioration. The level 1 (cortico-sub-cortical) is defined by the persistence of the mimic and flexion response to painful stimulation. The level 2 (diencephalic) is characterized by stereotypic responses to pain and lack of mimic. At these two levels, the fronto-orbicular and vertical oculo-vestibular reflexes are persistent. These reflexes disappear when the status impair caudodal to the level 3 (meso-diencephalix junction). The photomotor reflex disappear at the level 4 (mesencephalic), where the motor response to pain may be very poor, or may be a bilateral extension. The horizontal oculo-vestibular reflex is always persistent, except for the level 5 corresponding to a pontine lesion. The meso-diencephalic level 3 appears to be a critical impairment point: as long as the level is not overpassed, the half of the patients do improve and 10% only die. More than 75% of those who improve from this level have an excellent recovery. The restructuration probability is diminished by the half when the level of mesencephalic misfunction is reached.