Large vestibular aqueduct syndrome: anatomic and functional parameters.

OBJECTIVES/HYPOTHESIS: To correlate imaging and audiologic findings in patients with large vestibular aqueduct syndrome (LVAS).

STUDY DESIGN

Retrospective analysis.

METHODS

Thirty-eight patients with LVAS evident on magnetic resonance imaging with available clinical and audiometric data were selected from the databases of the study institution. Images were analyzed for endolymphatic sac and duct size, evidence of incomplete cochlear partitioning, and endolymphatic sac signal heterogeneity. The endolymphatic duct was measured in two different locations: near the vestibular aperture (ED(VA)) and at the midpoint between the common crus and the operculum (ED(MID)). Imaging data were correlated with audiologic variables.

RESULTS

There was significant correlation between ears for the audiologic and anatomic variables collected. Twenty-one (62%) patients had a fluctuating or progressive hearing loss, and 13 (38%) remained stable (four were not evaluable). At the time of the analysis, 41% of ears had a profound loss. Significant correlation was identified between the presence of endolymphatic signal heterogeneity and worse pure tone average (PTA). ED(VA) measures were significantly larger among ears with a progressive pattern of hearing loss when compared to those that were stable. Also, ED(VA) correlated with PTA and the presence of progressive hearing loss, but ED(MID) had no such a relationship.

CONCLUSIONS

Evidence of endolymphatic sac signal heterogeneity and larger measures of endolymphatic width when measured near the vestibule (ED(VA)) are markers of poorer hearing in these patients. By contrast, midpoint measures of the endolymphatic duct (ED(MID)) have no correlation with audiometric parameters.