This study examines the course of intelligence in children with neurofibromatosis type 1 (NF1) and factors influencing changes. In this cross-sectional and longitudinal study, 397 children were assessed at ages 3, 6, 11, and 15 years using a neuropsychological test battery. Comparisons of demographics and scores were conducted across and within cross-sectional and longitudinal groups. Cross-sectionally, 15-year-olds outperformed 11-year-olds on Performance IQ (PIQ). A reduced PIQ at age 11 years was found that appeared to recover by age 15 years in the longitudinal group. The mother's level of education, the mode of inheritance, or attention-deficit hyperactivity disorder were not predictive of these changes. Overall, intelligence remains stable in children with NF1 between 3 and 15 years of age. The gap between PIQ and VIQ decreases over time. Neurocognitive monitoring is recommended during the critical period between ages 6 and 11 years due to risks of attention and learning issues.
Abeelen et al. (Tue,) studied this question.