This review addresses the current status of
steroid therapies for hearing and vestibular disorders and how certain misconceptions may be undermining the efficacy in restoring normal ear function, both experimentally and clinically. Specific misconceptions addressed are that
steroid therapy is not effective,
steroid-responsive
hearing loss proves an underlying inflammatory problem in the ear, and
steroids only have application to the
hearing disorders listed below.
Glucocorticoid therapy for hearing and balance disorders has been employed for over 60 years. It is recommended in cases of
sudden hearing loss, Meniére's
disease, immune-mediated
hearing loss, and any vestibular dysfunction suspected of having an inflammatory etiology. The predominant
steroids employed today are
dexamethasone,
prednisone,
prednisolone, and
methylprednisolone. Despite years of use, little is known of the
steroid responsive mechanisms in the ear that are influenced by
glucocorticoid therapy. Furthermore, meta-analyses and clinical study reviews occasionally question whether
steroids offer any benefit at all. Foremost in the minds of clinicians is the immune suppression and anti-inflammatory functions of
steroids because of their efficacy for autoimmune
hearing loss. However,
glucocorticoids have a strong binding affinity for the
mineralocorticoid (
aldosterone) and
glucocorticoid receptors, both of which are prominent in the ear. Because the auditory and vestibular end organs require tightly regulated endolymph and perilymph fluids, this ion homeostasis role of the
mineralocorticoid receptor cannot be overlooked in both normal and pathologic functions of the ear. The function of the
glucocorticoid receptor is to provide anti-inflammatory and antiapoptotic signals by mediating survival factors.