Abstract

Background
Numerous reports have been published concerning the clinical findings of ischemic stroke in the territory of the anterior inferior cerebellar artery (AICA). However, a detailed description of the ocular tilt reaction (OTR) as a cardinal sign of AICA infarction has not previously been reported. Objectives: To describe the characteristics of OTR with acute infarcts in the territory of AICA. Patients: Two patients with acute infarcts in the territory of AICA on the left side presented with acute vertigo, left-sided hearing loss, and imbalance. In each patient, MRI showed acute infarction in the left middle cerebellar peduncle and left dorsolateral pons. Both patients had tonic ipsiversive (i.e., left side) conjugate ocular torsion and skew deviation with left hypotropia; one had a head tilt. Subjective visual vertical testing showed pathologic tilting to the left side in both patients. Audiometry and elecronystagmography documented absent auditory and vestibular function on the left side.
Conclusion
The OTR in these patients likely resulted from infarction of the inner ear or the root entry zone of the 8th nerve. Questions: 1. The locus of injury responsible for ipsiversive OTR in these patients 2. Can floccular lesion cause OTR as in nodulus lesion