Neurophysiological examinations of brainstem functions before, during and after selective interventional neuroradiology i.e. selective intraarterial thrombolytic therapy of an acute occlusion of the basilar artery are reported. The success of the therapy was demonstrated by the reappearance of normal somatosensory potentials and of the blink reflex immediately after the thrombolysis. The BAEPs were continuously recorded during the thrombolysis. Normalization of the latencies and of the interpeak latencies at a very early stage of the therapy indicated the improvement of brainstem functions.