CHRONIC NON-SUPPURATIVE OTITIS MEDIA 323 suggestion that the condition is the end-result of deficient Eustachian tube ventilation in childhood implies that many cases result from chronic non- suppurative otitis media. Fibrosis in the middle ear is the significant pathological feature, and fibrous adhesions have been found between drumhead and promontory and between ossicles and promontory. Fibrous tissue may fill the niches of the oval and round windows, and fibrous thickening of the tympanic membrane will be seen on otoscopy as an opaque and lustreless drum, often with white plaques (Plate X, 16, 17) on the surface—previously called chalk patches. The membrane is frequently indrawn so that the lateral process of the malleus is prominent, and the membrane may be so retracted that it is partly or wholly adherent to the medial wall of the middle ear cavity, and its mobility is thus impaired. As a rule the only symptom is deafness, but tinnitus of a variable character and intensity is present in some cases. The deafness is of the conductive type, and may be stationary or progressive. DIAGNOSIS. This can be made from abnormality of the tympanic membrane and the absence of the characteristics of otosclerosis with which the condi- tion is sometimes confused. In a few cases the coexistence of both condi- tions cannot be excluded. Eustachian catheterization and inflation may reveal partial or complete obstruction, or a normal air entry which, how- ever, because of the presence of adhesions and other middle ear changes, does not produce replacement of the drumhead. PROGNOSIS. Restoration of normal hearing is unlikely except in a few early cases. The precept of prevention being better than cure is evident in this condition, and the results of sweep testing of schoolchildren with the detection of early deafness and its effective treatment are bearing fruit. TREATMENT. In its early stage active steps must be taken to prevent pro- gress of the condition. The removal of tonsils and adenoids, the treatment of sinus infection and the aspiration of middle ear secretions all contribute towards the prevention of the formation of fibrous tissue in the middle ear. The observation of all cases of acute otitis media until a cure results is a further preventive measure. Advanced cases of tympanosclerosis present a difficult problem and in many cases the only satisfactory treatment of the deafness is the provision of a hearing aid. Exploration of the middle ear cavity by tympanotomy will display the underlying pathology, and will determine the possibility of relieving the condition by removing the fibrous tissue and restoring mobility to the sound-conducting mechanism. Staped- ectomy may succeed in some cases, but its successful outcome cannot be predicted. In older patients an associated or secondary perceptive deafness is a limiting factor.