Effect of High Jugular Bulb on the Hearing Loss Characteristics in Patients With LVAS: A Pilot Study

Both large vestibular aqueduct syndrome (LVAS) and high jugular bulb (HJB) are regarded as abnormalities commonly seen on the temporal bone CT. High jugular bulb has been found to erode the vestibular aqueduct, and there are several studies on jugular bulb vestibular aqueduct dehiscence. However, there is no study that specifically reports LVAS with concurrent HJB and its hearing loss relatedness. This study presents the pure tone audiometry differences between LVAS with HJB, and LVAS without HJB.

This was a case control study involving 36 bilateral LVAS with concurrent unilateral HJB patients, total of 72 ears. Intra-person comparison was done, by dividing ears into two groups: the case group, 36 ears (LVAS with HJB); and the control group, 36 ears (LVAS without HJB). Air conduction thresholds (250-4000 Hz), bone conduction thresholds (250-1000 Hz), and air bone gap (250-1000 Hz) were analyzed and compared between groups.

There were statistically significant differences in AC thresholds at 250, 500, 2000, and 4000 Hz between the groups, p < 0.05. But there was no statistical significant difference at 1000 Hz, p > 0.05. There were statistical significant differences in BC thresholds at 250 and 500 Hz, p < 0.05, but there was no statistical difference at 1000 Hz. There were no significant differences in air bone gap at 250, 500, and 1000 Hz between the two groups.

LVAS with concurrent HJB was found to have higher air conduction thresholds, especially at 250, 500, 2000, and 4000 Hz. Bone conduction thresholds were higher at 250 and 500 Hz. Air bone gap at 250, 500, and 1000 Hz, were not significantly higher in LVAS with concurrent HJB.