Lermoyez syndrome revisited: 100-year mystery

Objective: This study revisited seven patients with Lermoyez syndrome over the past 25 years using an inner ear test battery to elucidate its mechanism. Methods: From 1992 to 2017, we have experienced 4096 patients with Meniere's disease (MD) and seven patients (5 males and 2 females, 8 ears) with Lermoyez syndrome. Two of the Lermoyez patients were elderly, aged 71 and 85 years. An inner ear test battery comprising audiometry, ocular and cervical vestibular-evoked myogenic potential (oVEMP and cVEMP) tests, and caloric test were performed. Results: Significant improvement of mean hearing levels (MHLs) was identified at low and middle frequencies after vertiginous attack, but not at high frequencies. Inner ear deficits in Lermoyez patients ran from abnormal hearing (100%) to abnormal cVEMP (43%), caloric (38%) and oVEMP (0) tests, exhibiting a significantly declining sequence. This declining sequence differed from that in MD. Conclusions: Lermoyez syndrome is extremely rare, with prevalence relative to MD of 0.2%. The mechanism is considered as blockage in the ductus reuniens caused by dislodged saccular otoconia. Aging and trauma are two precipitating factors for the dislodged saccular otoconia, which may explain why Lermoyez syndrome occurs most frequently in males and some elderly.