Bilateral vestibulopathy with dissociated deficits in the superior and inferior vestibular systems.
OBJECTIVE
The aim of this study was to reveal the clinical characteristics of dissociated bilateral vestibulopathy (BV) affecting the superior vestibular nerve system on one side and the inferior vestibular nerve system on the other side. It is probable that BV does not always show bilateral deficits of the same vestibular nerve system.


METHODS
In a retrospective study of 2,752 consecutive new patients, 1,560 patients had undergone both caloric testing and cervical vestibular evoked myogenic potential testing. All 1,560 patients had also undergone a battery of tests including standardized neurologic, neuro-otologic, neuro-ophthalmologic, and audiological examinations.


RESULTS
Forty-three patients (2.8% of 1,560 patients) were given a diagnosis of dissociated BV. Among them, 10 patients (23%) had Meniere's disease and 6 patients (14%) had vestibular neuritis. Eighteen patients (42%) did not have any identifiable disease involving the peripheral vestibule, and 9 patients (21%) could be regarded as having a novel subtype of idiopathic BV.


CONCLUSIONS
Although dissociated BV might be induced by some of the same causes that provoke bilateral vestibular dysfunction, a definite proportion of the patients did not have any identifiable causes of dissociated vestibular dysfunction. Idiopathic cases could be categorized into a novel subtype of idiopathic BV.
Department of Otolaryngology, Faculty of Medicine, University of Tokyo, Tokyo, Japan.
Chisato
C
Fujimoto
Toshihisa
T
Murofushi
Keiko
K
Sugasawa
Yasuhiro
Y
Chihara
Muentaka
M
Ushio
Tatsuya
T
Yamasoba
Shinichi
S
Iwasaki
D000293:Adolescent; D000328:Adult; D000368:Aged; D002150:Caloric Tests; D002648:Child; D002675:Child, Preschool; D004576:Electromyography; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D007759:Labyrinth Diseases / Q000175:diagnosis* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009443:Neuritis / Q000175:diagnosis; D014722:Vestibule, Labyrinth / Q000503:physiopathology*; D055815:Young Adult