Prediction of the Reversibility of the Brain Stem Dysfunction in Head Injury Patients: MRI and Auditory Brain Stem Response Study

Abstract

16 cases of head injury patients were examined by magnetic resonance imaging (MRI) and auditory brain stem response (ABR) simultaneously in acute stage in order to investigate the possibility of the prediction for long term outcome. Among 13 primary brain injury patients, brain stem injury was seen on MRI in 9 cases (69%) and ABR abnormality was seen in 6 cases (46%). MRI and ABR findings were equal in 8 cases (75%). In 6 cases, only MRI could show positive brain stem findings while ABR remained normal. MRI was more sensitive in detecting primary brain stem damage. Abnormal ABR findings and normal MRI was seen only in secondary brain damage cases. In primary brain injury cases, unilateral MRI abnormality in the brain stem and normal ABR were the signs for good recovery even if the consciousness disturbance persisted for a long period. Contrary to this group, bilateral brain stem damage on MRI and/or absent ABR were the signs for poor recovery. From these findings, it was concluded that MRI is thus useful in predicting the prognosis of primary brain damage in the acute stage based on the degree of the brain stem damage.