Evolution of Meniere's Disease from MD 1.0, via MD 1.5, to MD 2.0

Background: Elder Meniere's disease (MD) patients ultimately lose their vestibular function. Objective: This study utilized an inner ear test battery to investigate evolution of MD. Methods: Total 278 elder MD patients aged >65 years were divided into three groups. Ninety-four patients with bilateral MD (188 ears) were assigned to Group A. The remaining 184 patients with unilateral MD were further divided into two groups. Group B consisted of 20 affected ears with normal vestibular function on the opposite ears, while Group C indicated 184 unaffected ears. All patients underwent an inner ear test battery. Results: Inner ear deficits in Group B declined from the cochlea via the saccule, utricle to semicircular canals. In contrast, Groups A and C did not significantly differ in the abnormality rates of cervical vestibular-evoked myogenic potential (cVEMP), ocular VEMP and caloric tests, indicating that Group C (unaffected ears) may partly share the same mechanism like Group A (affected ears), namely aging and hydropic effects. Conclusion and significance: Evolution of MD may progress from unilateral MD (MD 1.0), via unilateral MD coupled with asymptomatic hydrops on opposite ear (MD 1.5), toward bilateral MD (MD 2.0), where the number 1.0-2.0 means the number of clinically affected ears.