ABR findings in brainstem ischemia: occlusion of the left anterior inferior cerebellar artery.

ABR was measured ipsilaterally following permanent left anterior inferior cerebellar artery (AICA) occlusion to assess the discrepancy in recovery between blood flow and function in the rat brainstem. Three types of wave patterns were classified: in type 1, all components disappeared; in type 2, all components disappeared transiently, then re-appeared; and in type 3, only a significant increase in the latency difference between components I-IV was noted. In type 2. we suggest that all components re-appeared because cochlear blood flow was re-established quickly by collateral circulation.