Vibration-induced nystagmus in patients with vestibular schwannoma: Characteristics and clinical implications.
To investigate the clinical significance of vibration-induced nystagmus (VIN) in unilateral vestibular asymmetry and vestibular schwannoma.



Thirteen patients with vestibular schwannoma underwent the VIN test, in which stimulation was applied to the mastoid processes and sternocleidomastoid (SCM) muscles on the ipsilateral and contralateral sides of lesions. Preoperative VIN was measured, and changes in VIN were followed up for 6months after tumor removal. Significance of VIN was determined by evaluation of its sensitivity, correlation with vestibular function tests and tumor volume, and postoperative changes.



The overall pre and postoperative sensitivities of VIN were 92.3% and 100%, respectively, considering stimulation at all four sites. Maximum slow-phase velocity (MSPV) of VIN was linearly correlated with caloric weakness and tumor volume, especially when stimulation was applied to the SCM muscle. Postoperative MSPV of VIN exhibited stronger linear correlation with postoperative changes in canal paresis value and inverse correlation with tumor size upon stimulation of the ipsilateral SCM muscle than upon stimulation of other sites. During the 6-month follow-up period, persistence of VIN without changes in MSPV was observed even after vestibular compensation.



Evoking VIN by stimulation of the mastoid processes and SCM muscles is effective for detecting vestibular asymmetry. It could also help determine the degree of vestibular asymmetry and volume of vestibular schwannoma if stimulation is applied to the SCM muscle.



The results of this study could provide clues for the basic application of VIN in patients with vestibular loss and vestibular schwannoma.
Department of Otorhinolaryngology, Ilsan Paik Hospital, Inje University College of Medicine, Goyang, South Korea.
Jeon Mi
JM
Lee
Department of Otorhinolaryngology, Catholic Kwandong University College of Medicine, Incheon, Gyeonggi-Do, South Korea.
Mi Joo
MJ
Kim
Department of Otorhinolaryngology, Yonsei Univeristy College of Medicine, Seoul, South Korea.
Jin Won
JW
Kim
Department of Otorhinolaryngology, Myongji Hospital, Goyang, Gyeonggi-do, South Korea.
Dae Bo
DB
Shim
Department of Neuroradiology, Yonsei University College of Medicine, Seoul, South Korea.
Jinna
J
Kim
Department of Otorhinolaryngology, Yonsei Univeristy College of Medicine, Seoul, South Korea. Electronic address: fledermaus@yuhs.ac.
Sung Huhn
SH
Kim
D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008416:Mastoid / Q000502:physiology; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D009759:Nystagmus, Pathologic / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology*; D047368:Tumor Burden / Q000502:physiology; D014732:Vibration / Q000009:adverse effects*
Nystagmus; Vestibular loss; Vestibular schwannoma; Vibration