PMC8732767_01
Results of the auditory and vestibular function tests before and after surgery. (A) No change in hearing threshold levels before and 58-months after the operation. (B) The post-operative caloric test revealed that, regardless of cold or heat stimulation, there was no response in the right horizontal semicircular canal. RC, right cool; LC, left cool; RW, right warm; LW, left warm; UW, unilateral weakness; BS, baseline shift; GA, gain asymmetry; FI, fixation index. (C,D) Both the preoperative and postoperative VEMPs could be elicited in the right ear. VEMP, vestibular evoked myogenic potentials; oVEMP, ocular VEMP; cVEMP, cervical VEMP. (E) The HIMP gain values for the RL and RP canal were within the normal range. The gain value of the RA canal was significantly lower than that of the LA canal. The SHIMP gain value for the RL canal was within the normal range. HIMP, head-impulse paradigm; SHIMP, suppression head-impulse paradigm; LL, left lateral; LA, left anterior; LP, left posterior; RL, right lateral; RA, right anterior; RP, right posterior. (F) Post-operative 3D-MRI reconstruction images of the semicircular canal revealing three completely blocked semicircular canals in the right ear (as indicated by the white arrow).
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Hence, in January 2014, she was referred to our hospital where she underwent endolymphatic sac decompression of the right ear on March 27, 2014 (shown in Supplementary Figure 1A). The three semicircular canals were identified and skeletonized (shown in Supplementary Figure 1B). A series of auditory and vestibular tests were performed to evaluate her hearing and otolithic functions before and after surgery (Figure 1). There was no significant increase in the pure tone average threshold at 58 months after surgery (Figure 1A). The right lateral semicircular canal did not respond to the caloric test (Figure 1B), indicating that the lateral semicircular canal was obstructed successfully. The oVEMP and cVEMP could be elicited both preoperatively and postoperatively (Figures 1C,D). The HIMP test at 58 months after surgery demonstrated that the gain of the right anterior semicircular canal was lower than that of the left anterior semicircular canal (Figure 1E). The HIMP gain values for the right lateral semicircular canal and posterior semicircular canal were within the normal range. The SHIMP gain value for the right lateral semicircular canal was within the normal range (Figure 1E). The postoperative magnetic resonance imaging reconstruction showed that the three semicircular canals of the right ear were completely blocked (Figure 1F).