Auditory brainstem response findings in brainstem ischemia following selective occlusion of the anterior inferior cerebellar artery in the rat.
Auditory brainstem responses (ABRs) were measured ipsilaterally (n = 13) or contralaterally (n = 5) after inducing permanent right and left anterior inferior cerebellar artery (AICA) occlusion. Three types of wave patterns were classified when ABRs were recorded ipsilaterally. In type 1 (n = 4) all components disappeared; in type 2 (n = 2) all components disappeared transiently and then reappeared; and in type 3 (n = 7) only the latency difference between components I and IV increased. These findings indicate that all components reappeared in type 2 responses because cochlear blood flow was re-established quickly by collateral circulation, while type 3 changes reflected the relative sensitivity of the cochlea to ischemic damage when compared with the rest of the auditory pathways. When the ABRs were recorded contralaterally, characteristic findings included a delay in latency of component IV and a significant increase in inter-peak latency in components I-IV and IIb-IV.
Inui
H
H
Department of Otorhinolaryngology, Nara Medical College, Japan.
Murai
T
T
Matsunaga
T
T
D000818:Animals; D002545:Brain Ischemia / Q000503:physiopathology*; D001933:Brain Stem / Q000503:physiopathology*; D002531:Cerebellum / Q000098:blood supply*; D016057:Evoked Potentials, Auditory, Brain Stem; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time