Otitis media with effusion (OME) affects approximately 80% of children in the first 3 yr of life. Studies have demonstrated that children who have extended or frequent episodes of OME during infancy are more likely to experience cognitive or language delays and perhaps behavioral problems in their early school years. These sequelae are hypothesized to result from the mild-to- moderate, intermittent and usually temporary hearing loss which often accompanies OME in young children. However, the long term effects of OME have proven difficult to assess. Because OME is often asympytomatic and difficult to diagnose definitively in young infants, it is frequently undetected. Reliable assessment of hearing and cognitive and language development in young children is also problematic. To investigate the effect of OME on hearing in infancy, and later language development, cognitive function, and behavior, this study will electronically monitor the middle ear status of 350 infants in the home at frequent intervals from birth to 5 yr. Children with extended OME will be assigned randomly to conventional (CT) or experimental (ET) therapy groups. CT group subjects will be treated by their physicians according to their usual clinical practice. ET group subjects will receive usual medical therapy, but will also be offered early ventilation tube placement. Hearing parameters will be assessed in an age appropriate fashion by yearly Brainstem Auditory Evoked Potential tests and/or behavioral audiometry. Language development and behavior will be evaluated at 2, 3, and 5 yr, and cognitive function at 3 and 5 yr. Home stimulation, maternal IQ, SES, race, and related environmental variables will also be documented. Correlation of early middle ear status and hearing with environmental, developmental, and behavioral outcome data should allow assessment of the interrelationships between OME and these measures. This study will evaluate the efficacy of early identification and treatment of OME in infants and test the hypothesis that hearing acuity during infancy is critical for optimal cognitive, language and social development.