Objective: Our objective was to analyze the electrocochleography (ECoG) and cervical vestibular evoked myogenic potential (cVEMP) results of patients with noise-induced hearing loss (NIHL).
Materials and methods: The study included 20 patients with NIHL. Pure-tone audiometry, tympanic membrane ECoG, and cVEMP were performed on all patients. The patients were divided into two groups based on averaged thresholds at 4, 6, and 8 kHz; whereby, group 1 comprised patients who had a threshold higher than 68.3 dB HL, whereas group 2 comprised patients with a threshold lower than 68.3 dB HL.
Results: Group 2 had a significantly higher number of patients with abnormal cVEMP values (63% versus 28%) (p=0.028). There was no significant difference in the incidence of ECoG abnormality between the groups (p>0.05), but there was a significant difference in the incidence of recognizable ECoG potentials between the groups (p<0.05). When only patients with vertigo/dizziness were considered, the group with vertigo and a lower degree of hearing loss (group 2) showed a higher incidence of abnormal cVEMP (p<0.05).
Conclusion: Although the anatomical proximity of the sacculus to the cochlea leads to the consideration of a common involvement of these structures in NIHL, our results did not support the idea of a common and proportional involvement of the vestibular and auditory systems. Our study shows that saccular involvement is disproportionate to auditory involvement in NIHL.