MRI findings in vestibular paroxysmia - An observational study

Vestibular paroxysmia (VP) presents as episodic vertigo believed to be caused by neurovascular cross-compression (NVCC) of the vestibulocochlear nerve. We investigated whether NVCC occurred at a higher rate in VP, compared with controls and whether angulation of the nerve, the vessel involved and location of the point of contact were significant features.

Retrospective analysis was conducted of MR imaging performed in patients with VP and also patients with unilateral tinnitus (in whom the asymptomatic side was used as a control). Two independent, blinded reviewers assessed each case.

Nine patients with VP and 20 patients with unilateral tinnitus were included. NVCC was demonstrated in all 9 VP patients (100%), compared with 9 of the controls (45%), p = 0.0049. NVCC was mostly caused by a branch of the anterior inferior cerebellar artery (AICA). Nerve angulation at the point of contact occurred in 5 of the cases (44%), but in none of the controls (specificity = 100%), p = 0.0053. There was no correlation between site of contact and VP.

Our study supports the concept of NVCC in VP and additionally suggests that nerve angulation may be a specific feature. Neurovascular contact remains a common phenomenon in asymptomatic patients and therefore correlation with neuro-otology assessment remains essential.