Longitudinal Developmental Outcomes of Children With Prelingual Single-Sided Deafness With and Without a Cochlear...

Children with prelingual single-sided deafness (SSD) have difficulty understanding speech in noise and sound localization. They also have an increased risk of problems with their language and cognitive development. Moreover, untreated SSD can lead to cortical reorganization, that is, the aural preference syndrome. Providing these children with a cochlear implant (CI) at an early age may support improved outcomes across multiple domains. This longitudinal study aimed to identify those aspects of development that are especially at risk in children with SSD, and to determine whether early cochlear implantation affects the children's developmental outcomes.

Over the past decade, 37 children with SSD completed regular auditory, language, cognitive, and balance assessments. Twenty of these children received a CI before the age of 2.5 yr. The same developmental outcomes were assessed in 33 children with bilateral normal hearing who served as a control group. The present study describes spatial hearing, cognitive, and postural balance development outcomes. These were assessed using standardized tests for speech perception in noise (speech reception threshold in three spatial conditions), sound localization (mean localization error in a nine-loudspeaker set-up), cognitive skills (Wechsler Preschool and Primary Scale of Intelligence), balance (Bruininks-Oseretsky Test of Motor Proficiency), and preoperative cervical vestibular evoked myogenic potentials.

Longitudinal analysis showed that the children with SSD who did not receive a CI were at risk for poorer speech perception in noise, sound localization, and verbal intelligence quotient. On average, they had higher speech perception thresholds (1.6 to 16.8 dB, depending on the spatial condition), larger localization errors (35.4°), and lower verbal intelligence quotient scores (difference of 0.78 standard deviations). Children with SSD with a CI performed on par with the normal hearing children on the cognitive tests. In addition, they outperformed their nonimplanted peers with SSD on tests for speech perception in noise (up to 11.1 dB lower mean speech reception threshold, depending on spatial condition) and sound localization (9.5° smaller mean error). The children with SSD, with and without a CI achieved similar scores on behavioral tasks for postural balance.

The present study shows that early cochlear implantation can improve spatial hearing outcomes and facilitate typical neurocognitive development in children with prelingual SSD. Taken together with previously published data related to children's language development, the present results confirm that children with prelingual SSD can benefit from a CI provided at an early age to support their development across multiple domains. Several guidelines are suggested regarding the clinical follow-up and rehabilitation of these children.