[Clinical characterization of audiometric and vestibular evoked myogenic potentials in patients with large vestibular aqueduct syndrome].

OBJECTIVE

To investigate the clinical and diagnostic characteristics of audiometric findings and vestibular-evoked myogenic potentials in patients with large vestibular aqueduct syndrome (LVAS).

METHOD: Thirty LVAS subjects (60 ears) recruited received pure tone audiometry, acoustic immittance, auditory brain stem responses (ABRs), distortion-product otoacoustic emission (DPOAE), Vestibular evoked myogenic potentials (VEMP) and caloric test, and the diagnostic significance of the results was analyzed.

RESULT: All 30 cases (60 ears) showed progressive and fluctuating hearing loss, while 16 cases experienced dizziness when hearing fluctuated. Most of our cases showed sensorineural hearing loss, and 47 ears (94.0%) showed air-bone gap in the low frequencies, with mean gaps of (43 +/- 17) dB HL at 250 Hz, (33 +/- 18) dB HL at 500 Hz, in which the middle ear function showed normal. The acoustically evoked short latency negative response (ASNR) with medium latency (3.06 +/- 0.52) ms was elicited from 18 ears (64.3%). The mean amplitude of vestibular evoked myogenic potentials (VEMP) of 42 ears was (147.10 +/- 107.55) microv, and the threshold of VEMP of 19 ears was 75 dB nHL, of 7 ears was 65 dB nHL.

CONCLUSION

Characteristics of hearing performance, such as progressive and fluctuating hearing loss, air-bone gap at the low frequencies with normal middle ears, the ASNR, and increased amplitude and decreased threshold of the VEMPs, will help clinicians make initial diagnosis of LVAS, and provide a reference for further imaging examination.