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Aim

Motor skill impairment and cognitive dysfunction are commonly reported features of neurofibromatosis type 1 (NF1). We characterized and determined the relationship between motor impairment, gait variables, and cognitive function in children and adolescents with NF1.

Method

Motor function, gait, and neurocognitive abilities were assessed in 46 children and adolescents with NF1 (26 males, 20 females; age range 7–17y; mean age 11y 1mo, SD 3y 2mo). Tests to establish correlations between neurocognitive, motor, and gait variables were performed.

Results

Compared with normative data, 28/39 of our NF1 cohort demonstrated impaired performance for balance and upper limb coordination and 16/38 for running speed and agility. Gait data revealed a strategy to preserve balance at the expense of velocity, with the unexpected exception of a tendency for reduced base of support. Neurocognitive testing confirmed mean IQ in the low average range (86.0) and deficits in spatial working memory and strategy generation. Significant correlations between a number of neurocognitive measures and motor abilities and gait were identified. The largest associations were between gait width and spatial working memory (r=0.594) and running speed and agility with strategy generation (r=0.549).

Interpretation

We have identified a relationship between balance, running speed and agility, gait, and cognition in children with NF1. Findings suggest a shared abnormal neurodevelopmental process underlying some cognitive and motor abilities in NF1. Results are discussed within the context of evidence highlighting abnormal dopamine-mediated corticostriatal circuitry in NF1.