EOAE were examined repeatedly in 18 patients with a sudden hearing loss at low frequencies due to Meniere’s disease or cochlear hydrops. It was revealed that EOAE could be recorded at the time of the attack in 14 patients. TEOEA were detectable particulary in the low frequency part of the spectrum (1-3 kHz). After recovery of hearing TEOAE remain unchanged or reach normal levels. DPOAE reach normal levels. A favourable prognostic value of positive TEOAE as regards normalization of hearing was not proved by statistical analysis. Nevertheless in none of four patients with negative emissions improvement of hearing was observed. The authors submit a hypothesis concerning association between the magnitude of hearing loss at 1000 Hz and the detectability of TEOAE as well as restoration hearing. TEOAE were negative in 10 cases and DPOAE in 9 cases in the group of 10 patients with a sudden severe idiopathic hearing loss (ISHL). Reappearence of DPOAE and TEOAE was observed in four patients with ISHL. EOAE do not contribute to the estimation of the prognosis in ISHL. However the restitution of EOAE after the improvement of hearing gives an evidence of reversible changes of an active non-linear mechanisms of the inner ear in ISHL.

        Key words: EOAE, sudden deafness, Meniere’s disease, prognostic use.