Hearing-impaired children under age 6: 1977 & 1984.
D000367:Age Factors; D002675:Child, Preschool; D003638:Deafness / Q000453:epidemiology* / Q000534:rehabilitation; D005006:Ethnicity; D006311:Hearing Disorders / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D007223:Infant; D014481:United States