The relationship between early hearing detection and speech development in children

How early can hearing loss be caught, and what happens to a child's speech when it isn't? This research set out to answer that question by tracking 243 children across South Korea over a four-year span. All participants were born between March 2019 and August 2020 and screened through the Universal Newborn Hearing Screening (UNHS) program. The sample was split into three groups: 87 children whose hearing loss was detected before three months of age (early detection group), 64 children identified after six months (late detection group), and 92 children with normal hearing who served as controls. Speech and language outcomes were measured at six-month intervals using the Korean Sequenced Language Scale for Infants (K-SELSI) and the Preschool Receptive-Expressive Language Scale (PRES). Results showed that children in the early detection group achieved speech milestones at rates comparable to their hearing peers by age 36 months, with composite scores reaching 93.2% of age-expected norms. Late-detected children, by contrast, lagged behind with scores of just 74.6% at the same age. The gap between groups was most pronounced for expressive language, where early-detected children outperformed late-detected peers by 18.6 percentage points on average. Receptive language differences were smaller but still meaningful at 11.3 points. These findings reinforce the argument that newborn hearing screening programs, paired with timely intervention before six months, can substantially narrow the speech gap for children with hearing impairment. The practical takeaway is clear: screening delays cost children measurable ground in language development that becomes harder to recover with each passing month.