Significance of Baseline Inferior Vestibular Function on the Prognosis of Patients with Labyrinthitis

Acute spontaneous vertigo with idiopathic sudden sensorineural hearing loss (ISSNHL) can be diagnosed as labyrinthitis, which has a poorer prognosis than ISSNHL without vertigo. Thus, we aimed to identify the effect of the baseline vestibular function on the prognosis of labyrinthitis.

A total of 23 patients with labyrinthitis was retrospectively divided into the recovered group (complete recovery, partial recovery) and the nonrecovered group (slight improvement, no improvement). Differences in caloric weakness and gain in the video head impulse test (vHIT) between the two groups were compared. In addition, the prognostic value of the vHIT on each of the three semicircular canals in predicting hearing recovery was analyzed using a linear regression model.

In final pure-tone audiometry, 2 patients (8.70%) exhibited complete recovery, 4 patients (17.39%) had partial recovery, and 17 patients (73.91%) had slight or no improvement. The initial ipsilesional posterior canal (iPC) gain and the contralesional anterior canal (cAC) gain were significantly decreased in the nonrecovered group (p < 0.013 for iPC and p < 0.007 for cAC, Mann-Whitney U test). The mean hearing gain was positively correlated with the iPC gain (R2 = 0.36, p = 0.003, Spearman correlation analysis).

An abnormal iPC gain may be a poor prognostic factor for hearing recovery. Additionally, the vHIT on the three semicircular canals can provide prognosis and insights into the pathophysiological mechanisms in patients with labyrinthitis.