The inner ear disorder that restores hearing (“Le vertige qui fait entendre”) is rare. A vertigo attack leads to an improvement in hearing. It was first described in 1919 by the French otolaryngologist , Marcel Lermoyez.
Lermoyez syndrome(LS), as it is also referred to, is considered to be a form of Meniere’s disease (MD). MD is characterized by attacks of low frequency hearing loss, tinnitus, ear fullness and vertigo. Between attacks patients are most frequently asymptomatic. LS differs from MD that at the time of the attack, especially with the occurrence of the intense vertigo, the low frequency hearing loss substantially improves. Tinnitus and aural fullness may also reduce with the onset of vertigo.
It is believed that in patients with this disorder a blockage occurs in the ductus reunions in the inner ear. This blockage leads to a build up of pressure of the inner ear fluid that is also referred to as endolymphatic hydrops. With a sudden opening of the blockage the reduction of fluid pressure leads to improvement in the cochlear function. This is characterized by an improvement of hearing and some of the other symptoms.
During an attack of MD the fast phase of the nystagmus is usually directed away from the affected side, whereas with LS the fast phase of the nystagmus is directed towards the affected ear. Manzari and co-workers demonstrated by using vestibular evoked myogenic potentials (VEMP) testing that the otolithic function of the utricle is decreased in LS, in contrast to MD where it is usually increased. In both conditions the otolithic function of the saccule were unaffected.
With video head impulse testing(VHIT) they demonstrated that the vestibulo-ocular reflex(VOR) in the horizontal canal rapidly changed over time. This fluctuation in dynamic vestibular and cochlear function in LS seemed to be the same as in MD and for that reason LS and therefore concluded that LS may be just a variant of MD.
Since LS is so rare there are still many questions to be answered. For instance why does it occur in the first place? When looking at the bigger picture of the inner ear disorder that restores hearing, however, it seems to have little effect on the prevention, diagnostic work up and treatment. This stays the same as in MD.