Vestibular evoked myogenic potentials in ipsilateral delayed endolymphatic hydrops

We recorded vestibular evoked myogenic potentials (VEMPs) in 12 patients diagnosed as having ipsilateral delayed endolymphatic hydrops (DEH). Seventy-five percent (9/12) of the patients showed decreased or absent VEMPs in the affected ears. Almost all patients had normal VEMPs in the unaffected ears. In addition, in 4 patients, VEMPs were recorded before and 3 h after oral glycerol administration (1.3 g/kg body weight). VEMPs improved after glycerol administration in 2 of the 3 patients whose VEMPs had been abnormal in the affected ears before glycerol administration. None of the 4 patients presented significant changes in VEMPs in the unaffected ears after glycerol administration. Improvement of VEMPs after glycerol administration confirmed the existence of endolymphatic hydrops in patients with ipsilateral DEH. In conclusion, VEMPs are useful to evaluate the function of otolith organs in patients with ipsilateral DEH, and the glycerol test using VEMPs may be useful to detect endolymphatic hydrops in ipsilateral DEH.