Long-Term Auditory and Language Outcomes in Children With Early-Identified Mild Bilateral and Unilateral Hearing Loss

OBJECTIVES: More than half of the children identified in population-based newborn hearing screening programs (with permanent hearing loss) initially present with a mild bilateral or unilateral hearing loss (MBUHL). The longer-term effects of MBUHL (during the school years) on the development of early-identified children are still largely unknown. DESIGN: In a multicenter study, we evaluated outcomes in auditory functioning and spoken language development at school age for children who were identified with MBUHL and compared their development to children with normal hearing. Assessments were analyzed at two timepoints: early school years and later elementary school years. We used multiple regression analyses to examine the effect of laterality (unilateral versus bilateral mild hearing loss), hearing loss severity, age at amplification, and amplification use on outcomes in the group of children with MBUHL. RESULTS: A total of 80 children, 47 with hearing loss (27 unilateral and 20 mild bilateral) and 33 with normal hearing, who had been enrolled in a preschool study, were assessed during the elementary school years. Children were identified early at a median age of 4.8 mo (interquartile range [IQR], 2.5 to 6.9) for children with unilateral hearing loss (UHL) and 4.1 mo (IQR, 3.0 to 8.0) for those with mild bilateral hearing loss. Most children with MBUHL (85.1%) received amplification which was fitted at an overall median age of 15.3 mo (IQR, 5.9 to 30.3). School-age assessments were collected in the early school years at an average age of 7.6 yr (SD = 1.1) and in the later years at 10.3 yr (SD = 1.1). At both early and later school ages, children with MBUHL showed on average poorer outcomes than their peers with normal hearing on functional auditory outcomes (p < 0.001). Children with UHL tended to show poorer scores than those with mild bilateral loss on functional auditory abilities. The results for receptive vocabulary were not significantly different between the three groups (p = 0.30). However, after controlling for hearing-related variables, children with mild bilateral loss had significantly poorer receptive vocabulary scores than those with UHL (p = 0.007). More hearing aid use was associated with better scores in receptive vocabulary in both children with UHL and those with mild bilateral hearing loss. No significant change in scores was found between the early and later school years for any group in auditory function (p = 0.7) or in receptive vocabulary (p > 0.9). CONCLUSIONS: Despite early detection and intervention, as a group, children with MBUHL lag behind their peers with normal hearing in auditory functional outcomes and language development. These findings suggest that a substantial number of children with MBUHL will require early intervention support and may continue to require specific attention including monitoring and/or intervention in some areas during the school years.