Early identification of cognitive deficits in young children with neurofibromatosis type 1

Abstract

Neurofibromatosis type 1 (NF1) is a common neurogenetic disorder with a birth incidence of approximately 1 in 2700. The most commonly reported neurological complication of NF1 is cognitive dysfunction, which can negatively impact on academic achievement, behavioural function, and overall quality of life. The majority of cognitive-based studies on NF1 have focused on older children and adolescents. Very little is known about the specific developmental and cognitive abilities of younger children with NF1. The general aims of this thesis were to examine the developmental, cognitive, and behavioural profile of toddlers with NF1, as well as follow their developmental trajectories over time. Three studies are reported. The first cross-sectional study examined the mental, motor, and language skills of toddlers with NF1 (aged 21 and 30 months) and age-matched healthy comparison peers. The second cross-sectional study explored the cognitive functioning of 40-month old children with NF1, using a case-control design. The third study monitored the developmental progression of young children with NF1 and healthy controls over three specific time points (i.e. 21 months, 30 months, 40 months). Overall, the three studies contribute to our understanding of the cognitive profile of young children with NF1, with emphasis on phenotyping toddlerhood years between the ages of 21 and 40 months. The findings show that specific developmental and cognitive deficits are apparent in younger age groups of affected children, which has important clinical implications. Earlier detection of these cognitive deficits has allowed the identification of particular areas to target for remediation. This information can then be utilised by clinicians and educators to design and implement appropriately timed and effective early intervention as early as possible. Potentially, the risk for later cognitive difficulties can be minimised, which will be beneficial to the daily lives and developmental functioning of young children with NF1, both in the short and long term.