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.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
33
Strength of one weak muscle group and of the biceps of the dominant arm will be measured using a hand-held dynamometer. An average of three readings will be used as one observation. Three observations per patient will be obtained on one day with a minimum of 15 minute rest period between each observation.
New York School of Medicine
New York, New York, United States
Intra-class correlation coefficient of strength measurement in the clinically identified weak muscle
A sample size of 20 subjects with three observations per subject achieves 90% power to detect an intraclass correlation of 0.91 under the alternative hypothesis when the intraclass correlation under the null hypothesis is 0.75 using an F-test with a significance level of 0.05.
Time frame: 1 day
Intra-class correlation coefficient of strength measurement in the dominant biceps
A sample size of 20 subjects with three observations per subject achieves 90% power to detect an intraclass correlation of 0.91 under the alternative hypothesis when the intraclass correlation under the null hypothesis is 0.75 using an F-test with a significance level of 0.05.
Time frame: 1 day
standard error of measurement of measuring strength in the weak muscles
Time frame: 1 day
standard error of measurement of measuring strength in the dominant biceps muscle
Time frame: 1 day
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