Acoustically Evoked Short Latency Negative Response and Vestibule Function in Patients With Enlarged Vestibular Aqueduct.

OBJECTIVES

To investigate the associations between acoustically evoked short latency negative response (ASNR) and vestibular function in patients with large vestibular aqueduct syndrome (LVAS) before and after cochlear implantation (CI).

STUDY

DESIGN

Retrospective study.

SETTING

Tertiary medical center.

METHODS

The records of 64 patients (32 with bilateral LVAS and 32 with no inner ear malformations [IEMs]) who underwent unilateral CI were reviewed. Among them, the auditory brainstem response of 17 LVAS patients who presented with bilateral ASNRs was reassessed after CI, with a mean follow-up period of 4.18 ± 2.43 years.

RESULTS

The ASNR could be detected more from LVAS ears than from ears without IEMs (67.18% vs 12.5%, P < .001). Compared with the LVAS ears without ASNR, the ears with an ASNR presented better vestibular function, with a lower abnormal rate in the caloric test and vestibular evoked myogenic potentials (VEMPs), before CI. After CI, the LVAS patients showed a significant increase in the abnormal rate of the caloric test (29.41% pre-CI to 70.59% post-CI, P = .038). Notably, patients with a preserved ASNR maintained normal cervical VEMP (cVEMP) responses (100%), whereas those with no robust ASNR had a higher rate of abnormal cVEMP (77.78%, P = .002).

CONCLUSIONS

The presence of an ASNR in LVAS patients correlates with better vestibular function preservation both before and after CI. The function of otoliths in patients with LVAS is not significantly affected by CI. The ASNR may serve as a valuable noninvasive predictor of vestibular outcomes in LVAS patients.