Vestibular evoked myogenic potentials in middle ear effusion

Conclusion. The vestibular evoked myogenic potential (VEMP) responses were significantly affected by middle ear effusion (MEE). The VEMP was either non-responsive or significantly delayed. However, after the conductive hearing loss (CHL) was significantly reduced with tympanic aspiration, the VEMP latencies and asymmetry ratio returned to the range of healthy controls. In addition, the recovery of VEMP response was prompt and immediate. Objective. To evaluate the VEMP in various degrees of CHL resulting from MEE and to clarify the responses after the CHL was reduced. Materials and methods. VEMPs were collected from 21 unilateral subjects with MEE (8 male, 13 female, aged 21-79 years) using unilateral tone-burst stimulation. The pure tone audiograms and tympanograms were recorded. The effusion was then cleared with tympanocentesis. The VEMP responses were compared to those of the healthy volunteers and the responses after the MEE was reduced by tympanic aspiration. Results. The pure tone hearing thresholds decreased significantly with tympanic aspiration. Before tympanic aspiration, the VEMP response rate was 67% and increased significantly to 95% (p<0.05) after tympanic aspiration. The latencies of p13 and n23 were significantly prolonged before tympanic aspiration (p<0.01), and shortened to the normal range after tympanic aspiration. The VEMP asymmetry ratio was significantly decreased after tympanic aspiration (p<0.05).