Abstract
An otologic examiation of 582 school children, 1 st to 6 th graders, in the Tokyo area revealed that bilateral changes of the tympanic membrane such as redness or retraction had improved or disappeared as the children grew older. However, the unilateral changes, such as retraction localized to the posterior superior quadrant of the eardrum, persisted. The authors ascribed those unilateral changes to the inadequate development of the mastoid pneumatization due to inflammatory diseases.
