Neuropediatrics 2015; 46 - FV03-12
DOI: 10.1055/s-0035-1550672

Executive Dysfunction in Neurofibromatosis Type 1: Comparison to Idiopathic ADHD

M. Heimgärtner 1, S. Granström 2, V. Mautner 2, K. Lidzba 1
  • 1Department Pediatric Neurology, University Children's Hospital, Tübingen, Germany
  • 2Neurofibromatosis Outpatient Department, University Hospital Hamburg-Eppendorf, Hamburg, Germany

Aims: Neurofibromatosis type 1 (NF1) is a genetic disorder with various physical and cognitive symptoms. One of the core deficits in the neurocognitive profile of NF1 is executive dysfunction (ED). Consistently, deficits in impulse control, planning, and working memory have been found in patients with NF1. However, ED is also a hallmark of attention deficit hyperactivity disorder (ADHD) and approximately 50% of patients with NF1 fulfill the diagnostic criteria of ADHD, leaving a large number from the remaining population with subclinical attention problems. This suggests, ED in NF1 might simply be because of the comorbid ADHD, but the current research reveals that ED is present independently of an ADHD diagnosis. In an ongoing, large-scale, observatory study, we investigate whether patients with NF1 with and without ADHD differ from patients with idiopathic ADHD.

Methods: Up to now, we included 52 children with NF1 + ADHD, NF1-only, or idiopathic ADHD, aged between 6 and 11 years. We provided the parent questionnaire for the Behavior Rating Inventory of Executive Function (BRIEF), and assessed intelligence (WISC-IV) and severity of ADHD symptoms (Conners-3, DISYPS-KJ). Socioeconomic status (SES) was measured with the Winkler Index.

Results: There were no significant differences between the patient groups in sex, age, and SES, but the NF1-only group had a significantly higher IQ (mean, 101.38; SD, 7.95) than the NF1 + ADHD group (mean, 90.58; SD, 10.49). ADHD severity was significantly pronounced in the two ADHD groups, but did not differ between these two groups. Taking IQ into account, both the groups were significantly more impaired in impulse control (p = 0.032), working memory (p = 0.001), planning (p = 0.003), and monitoring (p = 0.002), when compared with the NF1-only group. The NF1-only group was neither affected in attention functions nor in executive functions.

Conclusion: Patients with NF1 + ADHD show a similar pattern of ED as patients with idiopathic ADHD, whereas patients with “pure” NF1 do not seem to be impaired. In contrast to previous research, we found comorbid ADHD to be the decisive factor for ED in NF1.

Keywords: neurofibromatosis type 1, executive dysfunction, ADHD.