LONG-TERM OBSERVATION ON HEARING CHANGE IN CHRONIC OTITIS MEDIA
A. Maeda, M. Node, T Seo, K. Fukazawa, M. Sone, M. Sakagami
Dept. of Otolaryngology, Hyogo College of Medicine, Nishmorntya, Hyogo, Japan
It has been believed that hearing loss develops usually in chronic otitis media (COM) due to the spread of middle ear inflammation to the inner ear. However, very few literatures are available to clarify the natural long course of hearing change in an individual patient with COM. In the present study, we reviewed hearing change in patients suffering from perforated COM without operation.
Subjects: Eighty-seven ears of 70 patients had COM with tympanic perforation and were observed without operation at the Hospital of Hyogo College of Medicine. Cholesteatoma patients were excluded. The mean follow up period was 10.7 years (5-22 years) and the mean age of the first examination was 51.3 years old. To avoid the effect of aging, 23 patients with normal eardrum on the other side were further analysed All audiograms were employed at the time of no otorrhea.
Results (1) All 87 ears tended to deteriorate hearing gradually under long- term observation. (2) In 23 patients with normal ear drum on the other side, hearing deterioration was 0.13 dB/year in normal side and 0.61 dB/Year in COM side. Both were significantly different p<0.02). (3) Deterioration of bone conduction in normal and COM sides were -0.007 and -0.04 dB/Y in 250 Hz, -0.09 and 0.04 dB/Y in 500 Hz, 0.17 and 0.63 dB/Yin 1000Hz, 0.24 and 0.7 dB/Y in 2000 Hz, and 0.8 and 0.82 dB/Y in 4000 Hz, respectively. (4)Change of A-B gap was larger in COM side (0.1 dB/Y) than in normal side (0.03 dB/Y). These findings suggested that thresholds of air and bone conduction levels deteriorated in COM with passage of time and that surgery should be recommended at the early stage of COM to prevent progress of hearing loss.