Prognostic value of auditory brain-stem responses for late postconcussion symptoms following minor head injury
Minor head injury is frequently followed by a subjective postconcussion syndrome. Brain-stem auditory evoked responses (BAER's) were found to be pathological in different small series of patients with a postconcussion syndrome who were examined months after sustaining a slight cranial or cervical trauma; abnormal BAER's have also been reported in larger groups of patients examined early after minor head injury. A relationship between these findings and late subjective symptoms has never been demonstrated. The results of a prospective study into the value of BAER's in the prognosis of a postconcussion syndrome after minor head injury are presented. In 103 patients with minor head injury, BAER's were recorded within 48 hours of the trauma. One year later, the patients were examined for headache, dizziness, depression, anxiety, subjective loss of memory and concentration, and irritability. Eighty percent claimed at least one symptom, most often irritability (54%), memory loss (47%), or depression (39%). Pathological BAER's were found with the same prevalence in patients with and without a postconcussion syndrome. This study confirms the disturbance of brain-stem function in some head-injured patients. However, the lack of correlation with a postconcussion syndrome limits the prognostic value of BAER recordings for postconcussion syndrome. The data suggest that BAER's not be used for medicolegal evaluation of patients with a postconcussion syndrome.