Stress in hearing and balance in Meniere's disease

Stress is an unavoidable every-day phenomenon. Physiological coping with stress depends on the appropriate release of stress hormones as well as their alleviation at the termination of the stress. Despite quite a body of research indicating that stress affects inner ear function, this concept has found little application in otolaryngology. Today's evidence clearly indicates that the inner ear is equipped to detect stress hormones and some of these hormones have been shown to affect the inner ear function. Major stress control pathways shown to affect the inner ear include several third order axes, the hypothalamus-pituitary-adrenal axis, the hypothalamus-pituitary-thyroid axis and the hypothalamus-pituitary-gonadal axis whose functioning are interactive and inter-dependent. Less well-studied are the second order hypothalamus-pituitary control axis and its interaction with other hormones. To explore these we carried out a retrospective study on a series of Ménière's patients who had undergone a neurotomy of the vestibular nerve in the dept of ORL at the Hopital Nord, Marseille. Ménière's patients were particularly appropriate for this study since stress has long been recognised as a factor associated with the triggering of the symptoms of this pathology. Patients with acoustic neuroma and facial spasm were taken as a control population. We investigated the level of a battery of stress hormones including prolactin beta-endorphin and growth hormone. The blood sample was taken on the morning before surgery. The most striking observation was the presence of hyperprolactinemia in 30% of the Ménière patients (more than 20 microg/l) with confirmation of prolactinoma in 6 patients. The level of beta-endorphin could also be elevated. Horner, K.C., Guieu, R., Magnan, J., Chays, A. and Cazal, Y. Neuropysychopharmacology, (2001) 26:135-138. These observations suggest that neuroendocrinological feedback pathways controlling stress can be disturbed in Ménière's patients and depression of hypothalamic dopaminergic inhibition of prolactin secretion might be implicated. A further study on non-operated Ménière's patients presenting hyperprolactinemia and on dopamine agonist treatment, is needed in order to assess the role of stress in Ménière's patients. Progress in this domain could open the door towards integration of the stress concept into clinical management of various inner ear disorders.