Prevalence and characteristics of children with serious hearing impairment in metropolitan Atlanta, 1991-1993.

OBJECTIVES: There is a paucity of data describing the epidemiology of serious hearing impairment among children in the United States. This report provides information on the prevalence of serious hearing impairment among children born in the 1980s and living in the metropolitan Atlanta area in 1991-1993 and on the characteristics of children with serious hearing impairment.

METHODS: Data for this report are drawn from the Metropolitan Atlanta Developmental Disabilities Surveillance Program, an ongoing, active case-ascertainment system for mental retardation, cerebral palsy, hearing impairment, and vision impairment among children 3 to 10 years of age. Hearing impairment was defined as a bilateral, pure-tone hearing loss at frequencies of 500, 1000, and 2000 Hz averaging 40 decibels or more, unaided, in the better ear. Both severity and type of hearing loss were examined. Cross-sectional as well as birth cohort prevalence rates of serious hearing impairment were computed by sex and by race. The presence of mental retardation, cerebral palsy, vision impairment, or a seizure disorder was also assessed. An attempt was made to determine the probable etiology of a subset of the cases.

RESULTS: The average, annual prevalence rate for moderate to profound hearing loss was 1.1 per 1000. The prevalence rate increased steadily with age. Ninety percent of all cases for which the type of loss was recorded were sensorineural. The highest rate was seen among black male children (1.4 per 1000). Thirty percent of case children had another neurodevelopmental condition, most frequently mental retardation. Black male children also experienced the highest rate of presumed congenital hearing impairment. The mean age at which children with presumed congenital hearing impairment first met the surveillance case definition was 2. 9 years. A probable etiology could only be found for 22% of cases born in the study area.

CONCLUSIONS: The data presented here provide information on the descriptive epidemiology of serious hearing impairment among United States children. The reasons for the higher rates among black children, especially males, may be a fruitful direction for further research.