Abstract
Concerning factors for the hearing recovery of sudden deafness, various studies have been done, but there are still many unknown things.
On 600 cases (604 ears) of sudden deafness examined within two weeks after onset and observed until the fixed time of hearing, the factors of prognosis were studied in groups of various days after onset. Data obtained were statistically examined using λ2 test and analysis of variance etc., and the following results were obtained.
1) The severer hearing loss, the worse hearing recovery. This tendency was noted earlier in the low frequencies than in the high ones. Even within four days after onset, in cases that mean hearing loss of 250, 500, 1k, 2k, 4k Hz was above 80dB, especially in cases of severe deafness above 90dB, prognosis was poor.
2) The marked hearing recovery was observed within two weeks after onset, and the faster recovery in this period, the better prognosis. The hearing recovery was worse and the fixation of hearing was about one week earlier in the high frequencies than in the low ones.
3) In cases within ten days after onset, prognosis was poorer in those with vestibular symptoms than without then. Furthermore, prognosis was poorer in vertigo than in dizziness concerning the properties of vestibular symptoms.
4) Many cases with positive ABLB test revealed complete recovery. However, the prognosis was not related with the result of other recruitment test, age and time from onset to initial examination, etc.
5) Among various factors concerning the prognosis, the most important factor is the degree of hearing loss on the day after onset by multiple regression analysis.
