A Single Center Pilot Study to Assess the Intra-observer Reliability of Measuring Muscle Strength Using a Hand Held Dynamometer in Children and Adults With Neurofibromatosis Type 1 (NF1) and Type 2 (NF2)

Patients with clinically confirmed neurofibromatosis type 1 (NF1) or neurofibromatosis type 2 (NF2) or a known neurofibromatosis (NF) mutation aged 5 years and above will be eligible to participate and will be recruited from the neurofibromatosis clinic. Given the need for identifying measures that can reliably and sensitively measure focal muscle weakness and allow for measuring muscle strength as a functional outcome in therapeutic clinical trials in NF, this pilot study will assess the reliability of measuring muscle strength in NF1 and NF2 using a hand-held dynamometer.