Vestibular histopathology of the human temporal bone. What can we learn?

Histologic sections of the human temporal bone display snapshots of the entire lifetime integrated into the moment the bone enters fixative. The bulk of the literature on vestibular histopathology is anecdotal and descriptive in nature, rather than quantitative. This is because the means of describing and measuring patients' vestibular symptoms are poorly developed, and the complex geometry of the vestibular labyrinth complicates efforts to study it in serial histologic sections. Histopathologic findings in the common peripheral vestibulopathies, including Meniere's syndrome, benign paroxysmal positional vertigo, viral labyrinthitis, vestibular neuronitis, and ototoxicity, have all been described. A new quantitative method for assessment of vestibular otopathology using Nomarski optics has recently been reported. It has been successfully applied to create a normative database of age-related changes in the vestibular hair cell populations which, in turn, has been used to study the effects of aminoglycoside ototoxicity and Meniere's syndrome. These data provide the first meaningful opportunity to make structure-function correlations between vestibular function testing and temporal bone pathology in humans. Wider clinical application of vestibular function testing and postmortem temporal bone donation should be promoted by all investigators interested in accumulating the resources necessary to gain a deeper understanding of the human vestibular system in health and disease.