We are conducting research to understand why spoken language outcomes vary so widely for deaf children with cochlear implants. Here is some information about three of our recent studies.
1. Pre-implant predictors of later language outcomes (Hardman, Kyle, Herman and Morgan, 2022)
It is important to identify pre-implant predictors of later post-implant language outcomes for deaf children with cochlear implants. This will enable clinicians to guide parents as to likely long-term outcomes post cochlear implantation. We investigated the relationship between pre-linguistic social communication skills and age of cochlear implant for later language outcomes in a large sample of deaf children. A retrospective cohort study was conducted of clinical outpatient records for 75 children with cochlear implants.
We found that the age at which children received their cochlear implant was the strongest correlate of post implant expressive and receptive language outcomes. We then divided the group into early implanted (<18 month) and late implanted (>18 months) children. For the early implanted group, pre-linguistic social communication skills were the strongest pre-implant correlate of language outcomes four years post-implant. However there were no significant pre-implant correlates of language outcomes for late implanted group.
The findings suggest that long-term language outcomes after cochlear implantation are the product of a set of communicative, cognitive and environmental factors. Early pre-implant social communication skills are particularly important for children who receive implants before the age of 18 months.
2. Diagnosing developmental language disorder (DLD) in deaf children with cochlear implants (Hardman, Herman, Kyle, Ebbels and Morgan, 2023)
We set out to explore the plausibility of diagnosing developmental language disorder (DLD) in deaf children with cochlear implants. After receiving a cochlear implant, many deaf children develop spoken language skills similar to their hearing peers. Other children, however, experience persistent delays in learning spoken language, despite protective factors being in place. This suggests that they have DLD, but at present there is little consensus on how to diagnose DLD in deaf children.
We conducted a retrospective case study review of three children with cochlear implants. We examined their long-term language outcomes and undertook a careful analysis of possible protective and risk factors. We hypothesized DLD in one child who had experienced good access to sound, alongside good speech discrimination abilities and social development, and normal non-verbal cognition, but who presented with severe language learning difficulties. Identifying markers for DLD in deaf children has important clinical implications for diagnosis and intervention.
2. A national characterisation of deaf children with cochlear implants in Chile (Bustos-Rubilar, Kyle & Mahon, 2025)
As part of his PhD studies, Dr Mario Bustos conducted a national characterisation of deaf children with cochlear implants in Chile. This is important because since 2008 Chile has implemented regulations to provide a CI to deaf children at an early age. However, wide variability exists in cochlear implant outcomes and expectations, and few national studies are from Latin American countries. We were interested in finding out more about the impact of CI on speech perception and production, social inclusion, and parental satisfaction for deaf children in Chile.
We conducted a prospective study using hospital clinical records and an online questionnaire with 107 deaf children under 15 years old. This was a national profile as it represented 70% of deaf children who received a cochlear implant from 2017 to 2019.
We investigated the relationship between (1) social determinants of health, demographic and audiological factors, and (2)CI outcomes including communication at home, CAPII, SIR, Geers and Moog Scale, Social Inclusion, and Parental Satisfaction.
Our study showed that children with CI tended to live in more developed boroughs (.54) compared to the national average (.37). Communication and speech perception outcomes varied widely, yet more positive outcomes were presented for reported child social inclusion and parental satisfaction. We found an association between the measured outcomes and children’s age, socio-economic factors, CI use and CI training. This national study suggests that it is critical to integrate public services close to where each child with a CI lives in order to improve outcomes with the device. CI use and parental training might be crucial measures during CI treatment.
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