case_images: PMC10625405_01
case_images: Pure tone audiometry before surgery. Audiometry of the patient upon presentation of sudden hearing loss (A) and 1 year later showing a reduction in hearing (B).
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case_images: PMC10625405_01_fneur-14-1276991-g0001.jpg
case_images: F1
case_images: An A-B gap was present at low frequencies (Figure 1A). One year later, she returned to the hospital with hearing loss and severe vertigo, and her right hearing had deteriorated and scaled out (Figure 1B).
case_images: Contrast-enhanced MRI images using HYDROPS. The arrow heads and long arrows indicate the enlarged cochlea vestibule, respectively. Contrast-deficient images (black areas) indicate the presence of endolymph. A contrast-enhanced deficient image of the endolymph of the right ear was rarely observed preoperatively (A) but is observed postoperatively (B).
case_images: fneur-14-1276991-g0002.jpg
case_images: PMC10625405_01_fneur-14-1276991-g0002.jpg
case_images: F2
case_images: HYDROPS did not show endolymphatic hydrops in the affected inner ear, which is characteristic of MD; rather, a few contrast-deficient images indicated the endolymph (Figure 2A). MD often shows a decreased response in the caloric test, which is normal in the video head impulse test (vHIT). However, in this case, the caloric test results revealed unilateral weakness in the right ear (canal paresis, CP = 50%), and the vHIT showed decreased vestibulo-ocular reflex (VOR) gain in the lateral semicircular canal (Figure 3A). Six months postoperatively, contrast-enhanced MRI using HYDROPS revealed a contrast defect in the endolymph on the affected side, which was rarely observed preoperatively (Figure 2B).
case_images: Preoperative vHIT shows a decreased VOR gain in the right LSC and PSC (A). Postoperative vHIT shows that the decrease in VOR gain in the right PSC remained unchanged, but the decrease in VOR gain in the right LSC improved (B). Both preoperatively and postoperatively, vHIT shows normal VOR gain in the right ASC with no change (A, B). vHIT, video head impulse test; VOR, vestibulo-ocular reflex; LSC, lateral semicircular canal; PSC, posterior semicircular canal; ASC, anterior semicircular canal.
case_images: fneur-14-1276991-g0003.jpg
case_images: PMC10625405_01_fneur-14-1276991-g0003.jpg
case_images: F3
case_images: HYDROPS did not show endolymphatic hydrops in the affected inner ear, which is characteristic of MD; rather, a few contrast-deficient images indicated the endolymph (Figure 2A). MD often shows a decreased response in the caloric test, which is normal in the video head impulse test (vHIT). However, in this case, the caloric test results revealed unilateral weakness in the right ear (canal paresis, CP = 50%), and the vHIT showed decreased vestibulo-ocular reflex (VOR) gain in the lateral semicircular canal (Figure 3A). Five months postoperatively, the CP% was 52.4%, which was unchanged from the preoperative level; however, the VOR gain in the lateral semicircular canal improved in the vHIT group (Figure 3B).