Acute intracranial hypertension and auditory brain-stem responses. Part 2: The effects of brain-stem movement on the auditory brain-stem responses due to transtentorial herniation.
Movement of the upper brain stem (inferior colliculus) was correlated with the alterations in the amplitude of wave V of the auditory brain-stem responses (BER's) during supratentorial brain compression in cats. In vivo observation of the brain stem and postmortem inspection show that suppression of the amplitude of BER wave V reflects the extent of caudal displacement of the inferior colliculus. Marked suppression of the amplitude of BER wave V (approximately 30% of control) correlates with the beginning  of transtentorial herniation, and complete suppression of the wave V indicates complete transtentorial herniation of the brain-stem and supratentorial structures. The BER wave V is thought to be a sensitive index of caudal movement of the upper brain stem due to transtentorial herniation.
D000818:Animals; D001306:Auditory Pathways / Q000503:physiopathology*; D001927:Brain Diseases / Q000503:physiopathology; D001933:Brain Stem / Q000503:physiopathology*; D002415:Cats; D005072:Evoked Potentials, Auditory; D006547:Hernia / Q000503:physiopathology; D007245:Inferior Colliculi / Q000503:physiopathology; D007427:Intracranial Pressure; D009068:Movement