[Late and sudden recovery of sudden deafness or vestibular neuronitis]

Vestibular neuronitis (VN) and sudden deafness (SD) are well-defined entities. The abrupt appearance of symptoms in both disorders represents an important element for the diagnosis. In cases of VN, symptoms regress gradually over time as the peripheral function recovers, or the central nervous system compensates for the balance deficit. In cases of SD, the recovery occurs in about half the cases and is generally progressive. The chances to recover normal levels of hearing are better if the recovery occurs early after the onset of the deficit. The goal of the paper is to present new insights of these disorders based on four unusual cases and on an evaluation of the delay for the function's recovery.

1) We report two cases of VN and two of SD whose the recovery was late and sudden; 2) The recovery time after a SD was retrospectively analysed using the chart of 36 patients seen

Twenty-eight patients recovered hearing within 6 months following the deficit. In eight patients, an audiogram was performed months later and showed a normalization of hearing. In these patients, the exact time of the recovery remained unknown.

A few patients may recover their inner ear function more than 6 months after the deficit. The recovery of function after SD or VN does not always follow the generally accepted pattern, as it can be late and sudden. These observations raise new questions to the hypothetical etiologies of SD and VN.