Language Development and Disorder in Children with Sensorineural Hearing Loss: A UK Cohort Study

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Sensorineural hearing loss (SNHL) is a permanent hearing loss that can vary in severity from mild (20-40 dB loss) to profound (> 90 dB loss). Around 0.2% of children are born with SNHL, and 0.6% will have SNHL by the time they are in their teenage years. In the past, SNHL was often not detected until the preschool years or later. However, in recent years, medical and technological advances have revolutionised the identification, diagnosis, and treatment of children with SNHL. Since 2000, the majority of children born in the UK undergo a universal newborn hearing screen (UNHS) at or shortly after birth, which screens for SNHL of > 40 dB in both ears. This means that SNHL is typically identified much earlier than before (< 9 months). Consequently, children with bilateral, moderate or worse SNHL can receive the help they need to hear at a young age, whether that be through the fitting of hearing aids, cochlear implants, or access to intensive speech and language therapy. These advances have led to significant improvements in outcomes for children with SNHL. Nowadays, many children with SNHL go on to develop speech and language skills that are commensurate with their normally hearing peers, and show good educational attainments. However, there are a number of outstanding issues. First, there has been no recent large-scale assessment of outcomes in children with SNHL in the UK. Therefore, we do not know what the likely outcomes are for children born with SNHL in the UK today. Second, while the UNHS detects bilateral, moderate or worse SNHL, it does not routinely detect milder losses, or losses affecting one ear only. Therefore, congenital mild or unilateral SNHL in children is often detected after a delay, and sometimes not at all. We do know the effects of this on outcomes. Finally, despite these advances, a significant proportion of children with SNHL still have difficulties in acquiring spoken language, and in learning to read. However, we do not know how many have difficulties, and precisely what difficulties they have. Moreover, at present, it is not possible to predict which children will go on to develop normal language, and which will not. To address these issues we will carry out six studies. In the first study, we will test the communication, language, social, emotional and behavioural (SEB), and academic abilities of a large group of children with early-identified mild-to-profound bilateral SNHL. This will tell us how well these children are actually doing. We will then follow this group up over three years. This will help us to understand how the abilities of children with SNHL change over time, and identify what factors are important in causing these changes. In other studies we will measure the same outcomes in children with (i) mild SNHL, (ii) unilateral SNHL, and (iii) a rare form of SNHL known as auditory neuropathy spectrum disorder (ANSD). These studies will tell us what the likely outcomes for these groups are, and whether there is an advantage of early identification for outcomes in these groups. Finally, we will identify those children with SNHL who show particular difficulties in their oral language and/or reading abilities. We will determine how common these difficulties are, and how these difficulties compare to those of children with normal hearing who also have poor oral and/or written language. The findings will tell us about the likely outcomes for primary-school aged children born with SNHL in the UK today, whether they have mild, moderate, severe or profound losses, bilateral or unilateral losses, or ANSD. They will also tell us whether children with mild or unilateral SNHL would benefit from being identified at the UNHS. Finally, the findings will provide greater insight into the difficulties experienced by some children with SNHL in acquiring spoken language and in learning to read. This information will pave the way for new interventions that could help such children in the future.