DETECTION OF COCHLEAR DYSFUNCTION BY THE MEASUREMENT OF TRANSIENTLY EVOKED OTOACOUSTIC EMISSIONS IN GUINEA-PIGS WITH AUTOIMMUNE-INDUCED LABYRINTHITIS

For the evaluation of functional inner ear lesions caused by an autoim mune-induced labyrinthitis, transiently evoked otoacoustic emissions ( TEOAEs) were detected in guinea pigs before and after transfer of sens itized lymphocytes from animals suffering from a labyrinthitis induced by the foreign protein keyhole limpet hemocyanin (KLH). Initially TEO AEs were detectable from 47 of 62 ears (76%) in healthy guinea pigs. T hese animals then were used as recipients for sensitized lymphocytes f rom donors exclusively. Three months after cell transfer the incidence of TEOAEs was reduced to 48% in animals receiving lymphocytes from do nors sensitized with KLH intradermally and intracochlearly. In recipie nts of lymphocytes from donors sensitized only intradermally and in un treated animals no significant alteration of the TEOAE incidence was f ound. These findings showed strong correlation with those from scannin g electron microscopy of the organ of Corti, indicating that the measu rement of TEOAE is a useful, time-saving tool for the detection of coc hlear dysfunction caused by sensitized lymphocytes in experimental ani mal. The present findings also show that the migration of sensitized l ymphocytes actually leads to functional lesions in the cochlea.