[Follow-up studies and prognostic references for pre- and post-therapy pure tone audiometry and acoustically evoked...

In 95 patients with unilateral sudden deafness, pure-tone and speech audiometry was performed before, during and after drug therapy. Auditory brain-stem evoked responses (ABR) were recorded in all cases. Stapedial reflex audiometry and SiSi tests were also performed. The tone-audiometry thresholds for the frequencies 250, 500, 1000, 2000, 4000 and 6000 Hz were analysed, and likewise the ABR latencies for waves I to V and the I-III, III-V and I-V interpeak latencies. 57 patients showed a flat hearing loss before therapy, 31 patients a high tone loss and 7 patients a hearing loss for low frequencies. Recruitment was positive in 77%. After therapy 81% of the patients showed increased pure-tone thresholds of more than 20 dB. In 11 patients ABR showed signs for retrocochlear hearing loss; in 6 patients initially no waves could be reproduced. The tendency for remission was best in patients with flat hearing loss of less than 40 dB and normal or only moderate alterations of the ABR. In patients with severe hearing loss of greater than 40 dB and signs for retrocochlear lesions in ABR, the tendency of remission was worse. In these cases recruitment was mainly negative.