Assessment of vestibulocochlear organ function in patients meeting radiologic criteria of vascular compression syndrome of vestibulocochlear nerve – diagnosis of disabling positional vertigo

BACKGROUND This study sought to assess the vestibulo-cochlear organ in patients meeting radiologic criteria of vascular compression syndrome (VCS) of the eighth cranial nerve. MATERIAL/METHODS The authors performed a retrospective analysis of 34 patients (18 women, 16 men; mean age, 49 years) treated in between 2000 and 2007, with VCS of the eighth cranial nerve by MRI. Contrasted magnetic resonance imaging identified an anterior inferior cerebellar artery vascular loop adhering to the vestibule-cochlear nerve in all 34 cases. All patients were given pure tone audiometry, distortion product otoacoustic emissions, auditory brainstem response, and electroneurographic examinations. RESULTS Most-common symptoms were unilateral hearing loss (82%), unilateral tinnitus (80%), and dizziness (74%). Most-frequent abnormalities in performed examinations were specific auditory brainstem response changes (interpreted according to Möller's criteria) in 86% of cases and sensorineural hearing loss in pure tone audiometry (82%). Abnormal changes in electronystagmography were found in the absence (12%) or weakness (35%) of a caloric response. No patients were surgically treated. CONCLUSIONS Significantly, there is no more weakness or absence of the caloric response of a vestibular organ in a patient with vascular compression of the vestibulo-cochlear nerve. Despite an absence of electrophysiologic testing of vestibular organ dysfunction, most examined patients (meeting the radiologic criteria of VCS of the eighth cranial nerve) had subjective symptoms like vertigo and dizziness. Disabling positional vertigo should be considered in the differential diagnosis of vertigo when accompanied by tinnitus or deafness.