To evaluate the modifications in the mechanical properties of the middle ear in rheumatoid arthritis by assessing its resonance frequency.
Thirty patients with rheumatoid arthritis (RA) aged 20 to 68 years (mean age 45.8 +/- 12.4 yrs) were investigated by multiple frequency tympanometry and their data were compared with those obtained in a control group of 48 subjects aged from 19 to 65 years.
Normal values, calculated at the 95th percentile from the control group, ranged from 800 to 1250 Hz. Eleven RA patients (36.6%) displayed abnormal resonance values. These findings were monolateral in 9 patients and bilateral in 2 (in all a total of 13 ears). Nine out of 13 ears with abnormal multiple frequency tympanometry data were characterized by an increase in resonance and 4 by a decrease.
These findings were attributed to abnormal acoustic impedence of the middle ear and indicate a possible involvement of the ossicular diarthroses in RA. Our study suggests that RA may involve the incudo-malleolar and incudo-stapedial joints, altering the ossicular mechanisms in response to static air pressure modifications.