Abstract:
Background: Neurofibromatosis type 1 (NF1) is a rare genetic disorder with
a long list of cognitive symptoms. One of the core difficulties in the cognitive
area is attention deficit, culminating frequently in the diagnosis of Attention
deficit hyperactivity disorder (ADHD). Given that each of the two diseases by
themselves are associated with impaired cognitive functioning, the comorbidity
of ADHD in NF1 may be a specific risk factor for major impairments in the
affected patients. The goal of this work was to identify characteristics of the
cognitive profile(s) of NF1 with and without ADHD and to distinguish attention
dysfunctions in NF1 from those in neurotypical ADHD. Furthermore, this
work investigated the role of attention deficit in the intellectual development
of children with NF1.
Methods: 111 children with NF1 and/or ADHD (53 NF1ADHD, 28 NF1only, 30
ADHDonly), aged between 6 and 12 years, performed an extensive neuropsychological
test battery at three times within two years. Standardized assessments
regarding intelligence, memory, attention functions, executive functions,
and quality of life were performed in a time interval of 12 months.
Results: Firstly, the cognitive characteristics of children with NF1ADHD differ
markedly from those of children with NF1only. Comorbid ADHD in NF1 was
associated with lower intellectual ability, more attention problems, executive
dysfunctions, and lower quality of life. Additionally, certain attention dysfunctions
differed between NF1 and neurotypical ADHD. Secondly, attention functions
correlated with intellectual functioning in the short and long term and
predicted them in NF1. However, intellectual functioning in children with NF1
was not modified by changes in attention over the term of the research project.
Conclusions: [1] The NF1 patient group of this research project can be divided
into two distinct subgroups regarding their cognitive profile: one group
with almost unimpaired cognitive functioning (NF1only) and one group with affected
cognitive functioning (NF1ADHD). [2] Certain attention dysfunctions in
NF1 might rather be associated with the NF1-condition, than merely be the result
of comorbid ADHD. [3] Attention functions are dimensionally and causally
linked to intellectual development in NF1.