Study of the etiology of deafness in an institutionalized population in Colombia

To identify causative factors we screened 1,715 deaf individuals from 16 schools for the deaf in Colombia. We found evidence of environmental causation in 579 (33.8%) cases, genetic in 608 (35.4%), and in 528 (30.8%) we were unable to identify the etiology. The degree of hearing loss was severe to profound in 1,238 (72.2%), although in 987 (57.5%) of the deaf population studied the hearing impairment was not noticed until 2 to 5 years of age. The frequent association of deafness with other anomalies underscores the importance of a careful clinical and ophthalmologic evaluation in individuals with hearing loss. Our observations also emphasize the need for programs directed towards the prevention of hearing loss, including primary prevention as well as early diagnosis, investigation of possible genetic causes, and rehabilitation of deaf individuals.