Brainstem auditory evoked potentials and somatosensory evoked potentials in pontine haemorrhage. Correlations with clinical and CT findings.

Electrophysiological studies were performed on 17 patients with pontine haemorrhage. Most had had massive hypertensive bleeding, leading to death in 12 of them within 3 months. Of the 5 surviving patients, 2 had a poor outcome and 3 a moderately good outcome. Brainstem auditory evoked potentials (BAEPs) and somatosensory evoked potentials (SEPs) were recorded in all patients, mostly with serial recordings. BAEPs were pathological in all patients. The most important finding was a reduction in amplitude or loss of waves. With a loss of waves after wave II bilaterally all patients died; the 2 patients with a normal amplitude of waves I-V at least on one side, survived in good condition. Further prognostic conclusions were not possible. The correlation with the clinical state was limited and was best for small unilateral tegmental haemorrhages. Eleven of the 17 patients suffered bilateral loss of the N20 component of the median nerve SEP. All these patients died. In patients with unilateral loss of the SEP the outcome could be favourable even if the bleeding extended across the midline. 'Subcortical' SEPs were not significantly altered. EEG findings in 15 and visual evoked potentials in 4 patients showed preserved forebrain electrical activity even in patients in poor condition.