(HealthDay)—The prevalence of hearing loss in preschool children who had heart surgery in infancy may be above 20 percent, according to a study published in the January issue of The Journal of Pediatrics.

Madison A. Grasty, from the Children's Hospital of Philadelphia, and colleagues investigated the prevalence of hearing loss after cardiac surgery in infancy and factors associated with hearing loss. As part of a prospective study evaluating neurodevelopmental outcomes at age 4 years, 348 children who had repair underwent audiologic and neurodevelopmental evaluations.

The researchers found that the prevalence of hearing loss was 21.6 percent overall, 12.4 percent for conductive hearing loss, 6.9 percent for sensorineural hearing loss, and 2.3 percent for indeterminate hearing loss. Only 5.2 percent of subjects had screened positive for hearing loss before the study. Younger gestational age, longer postoperative duration of stay, and a confirmed genetic anomaly were associated with hearing loss after the researchers adjusted for patient and operative covariates. Furthermore, the presence of hearing loss was associated with worse language, cognition, and attention.

"These findings suggest that the prevalence of in after in infancy may be 20-fold higher than in the 1 percent prevalence seen in the general population," the authors write.