P70-F Vestibular-evoked myogenic potentials for the diagnosis of superior canal dehiscence syndrome

Background Superior canal dehiscence syndrome (SCDS) is a clinical entity characterized by vertigo and oscillopsia in response to sound (Tullio phenomenon), pressure (Hennebert sign) and vestibular stimulation with Valsalva maneuvers, disequilibrium, autophony, bone-conductive hyperacusis and pulsatile tinnitus. Vestibular-evoked myogenic potentials (VEMPs) is a technique used to determine the function of the otolithic organs. The aim of the study is to examine the VEMPs characteristics in patients with SCDS. Material and methods 5 patients with SCDS between 2016 and 2018 were included. VEMPs were recorded from the ipsilateral sternocleidomastoid muscle (cVEMP) and periocular sites (oVEMP). 500 Hz tone burst at 105 dB nHL was used as stimuli at 5 Hz stimulation rate and averaged for 200 repetitions. Bandpass-filtered between 20 Hz and 2 kHz. Statistical analysis included paired sample Mann-Whitney U test in the SPSS program. We compared the latency and amplitude of the affected ear with the healthy ear. Data shown as mean ± SE. Results The mean age of the test group was 61.4 ± 8.08 years with 3 males and 2 females. Comparing the affected ear and healthy ear: oVEMP amplitude (33.2 ± 5.9/8 ± 2.1 μ V, p 0.11); cVEMPamplitude (158.8 ± 41.2/125 ± 29.86 μ V, p > 0.56); cVEMP-p13 (15.2 ± 0.4/15.1 ± 0.7 ms, p > 0.8); In 100% of patients with SCDS, oVEMP amplitudes were significantly higher than normal values (p > 0.01 Mann-Whitney U). No statistically significant differences were obtained in the remaining parameters. Conclusions oVEMP amplitude in patients diagnosed as SCDS are significantly higher than normal values. These techniques have proven to be useful for diagnosis of superior canal dehiscence syndrome.