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Development is a complex process with many factors at play. We study a range of these factors, including motor abilities, attention, sleep, parental mental health, health comorbidities, and genes, in order to learn how young children with genetic syndromes develop.

We would like to share some of the more recent findings from our research on young children with Down syndrome, fragile X syndrome, and Williams syndrome.

This is by no means definitive and there are many more issues to be investigated and further understood. However, sharing these findings is important as they can help parents and practitioners to better understand how young children develop.

We would like to thank all the families, practitioners, and funders who made this research possible.

 

 

Associations between the APOE ε4 gene and attentional abilities across the lifespan in individuals with Down syndrome

 

How we use our attention impacts how we learn and develop. Many different factors affect people’s attentional abilities. This is also true for individuals with Down syndrome. One of these factors is genetics. 

In this study, we looked at a particular gene known as APOE. We measured the attentional abilities of children and adults with Down syndrome, some of whom carried a particular type of the APOE gene (ε4), and some of whom did not. The children’s attentional ability was measured using remote eye-tracking as in our study below, and the adults' attentional ability was measured using a reaction time task. We discovered that individuals with Down syndrome who carry the APOE ε4 gene are likely to have higher attentional ability as young children, but lower attentional ability as older adults.

Understanding this gene can help us to create better interventions for people with Down syndrome, especially when we consider genetics alongside other factors that affect development, such as family context and wider support.

 

Publication: D’Souza, H., Mason, L., Mok, K. Y., Startin, C. M., Hamburg, S., Hithersay, R., … Thomas, M. S. C. (2020). Differential associations of apolipoprotein E ε4 genotype with attentional abilities across the life span of individuals with Down syndrome. JAMA Network Open, 3(9), e2018221. https://doi.org/10.1001/jamanetworkopen.2020.18221

This research was conducted in collaboration with the LonDownS Consortium.

 

 

Attentional abilities and language development in infants and toddlers with Down syndrome, fragile X syndrome, and Williams syndrome

 

The ability to visually focus on something, and to move this attention to something else when relevant, is very important for learning and development. This is known as visual orienting. Until now, very little was known about visual orienting in infants and toddlers with neurodevelopmental disorders other than autism.

Our recent research studied visual orienting in infants and toddlers with Down syndrome, fragile X syndrome, and Williams syndrome. We used remote eye-tracking to measure visual orientation, and also assessed language ability.

We found that young children with Down syndrome are slower than typically developing children at disengaging and shifting their visual attention to something else. We also found that, irrespective of the group, faster shifting was related to better language ability. These findings suggest that the visual disengagement difficulties in young children with Down syndrome may contribute to language delay. 

 

Publication: D'Souza, D., D'Souza, H., Jones, E. J., & Karmiloff‐Smith, A. (2020). Attentional abilities constrain language development: A cross‐syndrome infant/toddler study. Developmental Science, e12961. https://doi.org/10.1111/desc.12961

This research was conducted in collaboration with the ELAN lab.

 

 

Parental depression and language development in infants and toddlers with Down syndrome

 

In the general population, parental depression is often associated with difficulties in child language development. In this study, we measured the development of language, motor, and cognitive abilities in young children with Down syndrome from 8 months up to the age of 4 years, alongside parental depression.

We found that in cases where parents reported depression, the child’s ability to express language developed at a slower rate. It may therefore be especially important to support these families.

 

Publication: D’Souza, H., Lathan, A., Karmiloff-Smith, A., & Mareschal, D. (2020). Down syndrome and parental depression: A double hit on early expressive language development. Research in Developmental Disabilities100, 103613. https://doi.org/10.1016/j.ridd.2020.103613

This research was conducted in collaboration with the LonDownS Consortium.

 

 

Sleep and language development in infants and toddlers with Down syndrome, fragile X syndrome, and Williams syndrome

 

We found that sleep is disrupted for infants and toddlers with Down syndrome, fragile X syndrome, and Williams syndrome. During the night these infants/toddlers slept less and woke for longer than is typical, in the general population, for their chronological age.

Importantly, the more sleep children with Down syndrome and Williams syndrome had, the larger their receptive vocabulary (understanding of words). This could not be analysed for those with fragile X syndrome due to low numbers of participants.

The findings suggest that from a young age, sleep is disrupted in these genetic syndromes and may impact on the child’s language development. Finding ways to improve sleep early on in childhood may be an important step for improving language development. 

Press release

Publication: D'Souza, D., D’Souza, H., Horváth, K., Plunkett, K., & Karmiloff-Smith, A. (2020). Sleep is atypical across neurodevelopmental disorders in infants and toddlers: A cross-syndrome study. Research in Developmental Disabilities97, 103549. https://doi.org/10.1016/j.ridd.2019.103549

This research was conducted in collaboration with the ELAN lab.

 

 

Health comorbidities and cognitive abilities across the lifespan in Down syndrome

 

Many people with Down syndrome have co-occurring multiple health issues. We have conducted research to see prevalence of different health issues in the LonDownS cohort. Medical history was collated for 602 individuals with Down syndrome from 3 months to 73 years. 

 

Implications for clinical practice

  • Clinical guidance tends to be focussed on the needs of children with DS, but the pattern of comorbidities varies across the lifespan and surveillance needs to be adapted accordingly:
    • Epilepsy is more common in older adults compared to other age groups, and this is likely associated with the development of dementia.
    • Obstructive sleep apnoea requires on-going surveillance throughout the lifespan.
    • Thyroid disorders, particularly hypothyroidism, become more common with ageing.
    • Reflux is a common concern in children with DS.
    • Hearing and vision problems remain an important consideration throughout life, but these have different causes at different ages.
      • For hearing, otitis media with effusion is a common issue in childhood, while other causes of hearing loss become important in adulthood.
      • Vision problems increase across the lifespan, with the increased occurrence of cataracts in adulthood.
  • Unlike in the typically developing population, most mental health conditions are equally common in males and females, requiring similar surveillance in both sexes to ensure equitable care.
  • Neurodevelopmental disorders such as autism and ADHD are relatively common and do not show the same sex patterns as in the general population. These should be included in assessment and treatment guidance for all individuals.
  • To improve cognitive outcomes, a focus on interventions for those with DS from lower SES families and for those with autism or epilepsy is required.

Adapted from Table 7

 

Publication: Startin, C. M., D’Souza, H., Ball, G., Hamburg, S., Hithersay, R., Hughes, K. M., ... Strydom, A. (2020). Health comorbidities and cognitive abilities across the lifespan in Down syndrome. Journal of Neurodevelopmental Disorders, 12(1), 4. https://doi.org/10.1186/s11689-019-9306-9

This research was conducted in collaboration with the LonDownS Consortium.