Skull Vibration Induced Nystagmus Test in Ménière's Disease

BACKGROUND: Skull vibration induced nystagmus test (SVINT) also named Dumas’s test uses bone conducted vibrations applied to the cranium to reveal a vibration induced nystagmus (VIN) related to a vestibular asymmetry in unilateral vestibular lesions (UVL). VIN is relevant from a global canal (predominant) and otolith structures contribution. The aim of this work was to find out in Ménière’s disease (MD) SVIN possible characteristics when compared to those in other acute vestibular disorders, such as vestibular neuritis (VN), and describe its interest among other common vestibular explorations.METHODS: Thirty-two MD (60±18 yo) and 47 VN (59±13yo) patients were included. Each mastoid was stimulated at 100Hz for 10 seconds. The SVIN slow phase velocity (SPV) was measured in °/s and recorded with a VNG 3 D. All MD patients had on the same day an audiogram and SVINT, 23 had a caloric test (CaT) and HST, 18 a VHIT, 9 a subjective visual vertical (SVV) and 10 a VEMPs.RESULTS: SVIN was positive in 21/32 MD (66%) and 40/47 VN (85%), usually beating away from the lesion side. A VIN beating toward the lesion was observed in 3/21 (14%) MD and 1/42 (2%) VN. In VN, SVINT Sensitivity (Se) was equivalent to CaT (Se (83%) and VHIT (Se=88%) and in MD it was not different from CaT (Se=52%) but different from VHIT (Se=11%). SVIN-SPV was significantly higher in VN (7.3±4.9°/s) than in MD (3.89±3.9°/s) (P=0.001). SVIN-SVP horizontal component was correlated with results of the tests exploring the horizontal canal (Caloric-hypofunction and L-VHIT % asymmetry) in VN and only CaT in MD.CONCLUSIONS: SVINT is a sensitive first line examination test to reveal a vestibular asymmetry in peripheral vertiginous patients during the acute, subacute or chronic period. It is more often modified and with a higher SVIN-SPV in VN than in MD. SVIN is usually beating toward the intact side but is more often beating toward the lesion in MD than in VN. CaT, VHIT, HST, SVIN results are well correlated in VN but often discordant in MD. SVINT Se is equivalent to CaT to reveal MD or VN, but SVINT is more sensitive than VHIT in MD. In acute cases of vestibular syndromes its positivity associated with a negative VHIT suggests usually strongly a MD.