第68回日本めまい平衡医学会シンポジウム「VEMP:耳石器機能検査としての位置づけと今後の展開」
VEMPの臨床応用
2010 年 69 巻 3 号 p. 176-181
詳細
2010 年 69 巻 3 号 p. 176-181
Many papers had been published regarding clinical applications of the vestibular evoked myogenic potential (VEMP). The most important feature of the VEMP is measureable without specific devices. From a standpoint of the feature, furosemide loading VEMP (F-VEMP) testing and bone conducted VEMP (B-VEMP) are described in this paper.
Furosemide loading VEMP testing diagnosis of endolymphatic hydrops: The amplitude of the p13-n23 biphasic wave before (AB) and 60 minutes after (AA) 20mg of furosemide administration were measured. The improved ratio (IR) was calculated by the following formula: IR(%)=100×(AA-AB)/AB. If IR exceeded 43.5% or if a biphasic wave was detected after administration when the wave could not be detected before administration, the result of the F-VEMP test was considered to be positive. Positive results were shown in 40% of the affected ears in Meniere's disease patients. The ratio was similar to that of the conventional examinations for endolymphatic hydrops.
Bone conducted VEMP for vestibular examination in patients with perforated ear: The relationship between air-conducted VEMP (A-VEMP) and bone-conducted VEMP (B-VEMP) was studied in patients with unilateral vestibular disorders. The inter-aural ratio of B-VEMP was strongly correlated to those of A-VEMP. B-VEMP in patients with conductive hearing loss due to perforated ear were studied. Abnormal results were not found in any subjects without disequilibrium but were found in 54.0% of subjects with disequilibrium. The perforated ear showed lower responses than the intact ear in all subjects with abnormal results. Vestibular function can be evaluated with B-VEMP in patients with conductive hearing loss.
Conclusion: VEMPs are useful to examine the following conditions,
1. Furosemide loading VEMP
a. Diagnosis of Meniere's disease
b. Diagnosis of endolymphatic hydrops in ears with normal hearing function
c. Diagnosis of endolymphatic hydrops in ears with abnormal hearing function
2. Bone-conducted VEMP
a. Examination for vestibular function in perforated ears
