Prognosis of inner ear periphery and central vestibular plasticity in sudden deafness with vertigo.

Objectives: We sought to elucidate the clinical problems and otopathology of patients with sudden deafness with vertigo (SDV).
Methods: In 24 patients with SDV who had significant canal paresis (CP) at their first visit to our hospital between 1997 and 2001, we examined pure tone audiograms, caloric tests, and several questionnaires twice, at the first visit within 5 days after the onset and around 2 years after steroid therapy.
Results: These examinations revealed that improvements of auditory and vestibular function in patients with SDV tended to be correlated with one another. Sixteen of the 24 patients (66.7%) still had CP. This rate in SDV was significantly worse than that reported previously for vestibular neuritis (VN). On the other hand, patients with SDV with long-lasting CP had a faster reduction of head-shaking afternystagmus and of handicaps in their everyday life due to dizziness than did patients with VN and CP.
Conclusions: These findings suggest that SDV may deteriorate the inner ear function more severely but accelerate the central vestibular compensation more effectively than VN after the lesion. It is well known that vestibular neurectomy causes much more severe motion-induced dizziness after surgery than does labyrinthectomy. Taken together, these findings suggest different regions of damage in SDV (mainly the labyrinth, as in labyrinthectomy) and VN (mainly the ganglion, as in vestibular neurectomy).