Electrophysiological investigations of the brainstem in the vertebrobasilar reversible attacks.

A total of 70 selected patients affected by reversible ischemic attacks in the vertebrobasilar system were studied. 50 patients presented transient ischemic attacks (TIA), while the other 20 patients suffered from 1-2 protracted transient ischemic attacks (PTIA). All patients underwent brainstem acoustic evoked potentials (BAEP) and electrooculography (EOG) 7-20 days from the last reversible ischemic attack, when all signs and symptoms completely disappeared. The combination of BAEP and EOG gave objective evidence of brainstem dysfunction in 61 out of 70 patients. BAEP resulted abnormal in 26 patients (16 TIA, 10 PTIA), EOG in 49 (36 TIA, 13 PTIA). Serial controls at 3, 6, and 12 months were conducted in 27 patients. 5 patients showed a normalization for BAEP and 7 for EOG 12 months after the first examination.