Abstract

Objective: The purpose of this study is to investigate characteristics of nystagmus during attacks of VM, and to find a distinct clinical features compared to other migraine and peripheral vestibular disorders.
Methods
This study is a retrospective chart review of 82 patients satisfied with VM criteria, which is formulated by the new Bárány Society. Spontaneous and positional nystagmus provoked by various head positions were examined with video-nystagmography (VNG) in all patients. Bithermal caloric test and cervical vestibular evoked myogenic potential test (cVEMP) were also performed. The direction and peak slow-phase velocity (SPV) of nystagmus, unilateral caloric weakness and interaural difference (IAD) of cVEMP were analyzed. Control groups were lesion side in acute VN for nystagmus results and healthy side in PC-BPPV for caloric and cVEMP results. Chi-square test and Mann-Whitney U test were used for statistical analysis.
Results
During the acute attack, nystagmus was seen in 71.9% (59/82) of patients. Horizontal nystagmus was the predominant type. Peak SPV in VM patients was much slower than in the control group (2.37±1.73 deg/sec vs. 17.05±12.69 deg/sec, p<0.0001). There was no significant difference on the result of both caloric and cVEMP test, compared to those of control groups.
Conclusion
Nystagmus with horizontal directions and low SPV was dominant form in the attack of VM. Close observation of nystagmus can be helpful to make a correct diagnosis and to understand the pathomechanism of vertigo in VM.

• Keywords: vestibular migraine; ictal phase; nystagmus;