内リンパ水腫の聴力変動に見られる規則性

抄録

The purpose of this study is to clarify the hearing impairment in patients with idiopathic endolymphatic hydrops, i.e., Meniere's disease and acute low-tone hearing loss. We analyzed 734 audiograms obtained for 158 patients of 15-77 years (57 males and 101 females). Included were all audiograms showing a change in a patient's hearing score and audiograms obtained every other month if a patient's score did not change. The total 576 (734 minus 158) pairs of audiograms were classified into 4 groups according to severity of the first audiogram obtained: those showing normal hearing (Score 0), those showing low-tone hearing loss (>30dB, Score 1), those showing high-tone hearing loss (>40dB, Score 2), and those showing severe hearing loss (all frequencies>40dB, Score 3). Normal hearing in the right ear with low-tone hearing loss in the left ear was noted as R0L4. The second audiogram score was then analyzed in each group. We also studied the distribution of scores in 174 patients over time, i.e., within 1 year, from 1 to 3 years, from 3 to 10 years, and over 10 years. About 40% of patients with normal hearing showed low-tone loss and about 40% of patients with low-tone loss regained normal hearing, hearing improved in only about 10% of patients with high-tone or severe hearing loss. Once the disease enter its second year, the incidence of high-tone and severe hearing loss increased 12-fold and the incidence of bilateral lesions increased 5-fold. This simulative study suggests that half of patients diagnosed with low-tone hearing loss will suffer from high-tone and severe hearing loss within 10 years. Our findings clearly indicate that recovery from low-tone loss is possible in the early disease stage, but recovery from either high-tone or severe hearing loss is difficult at any stage. Thus, prevention of disease recurrence within a year of onset should be the primary goal of treatment for Meniere's disease and acute low-tone hearing loss. Data from patients questionnaires strongly suggest that physical and mental fatigue are the main causative factors of disease; therefore sufficient sleep, aerobic exercise, and relaxation may together be the best prevention therapy.