Characteristics of Nystagmus during Attack of Vestibular Migraine

Abstract

Objectives The purpose of this study is to investigate characteristics of nystagmus during attacks of vestibular migraine (VM), and to find a distinct clinical feature 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 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 of cVEMP were analyzed. Control groups were lesion side in acute VN for nystagmus results and healthy side in the patients with benign paroxysmal positional vertigo of posterior semicircular canal 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 of 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 °/sec vs. 17.05±12.69 °/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 중심 단어: ì „ì •íŽ¸ë‘í†µ, 발작기, 안진