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)

Study Overview
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Brief Summary
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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.

Official Title
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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).

Conditions
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Neurofibromatosis 1 and 2 (NF1 and NF2)

Intervention / Treatment
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* Behavioral: hand-held dynamometer


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: For cohort 1: Patients must have clinically confirmed NF1 using the NIH consensus criteria or a known NF1 mutation Ages 5 years and above < 5/5 strength on Manual Muscle Testing (MMT) testing in at least one muscle group tested on the day of enrollment Able to follow instructions and cooperate with exam to assess strength For Cohort 2 Patients must have clinically (NIH or Manchester criteria) or genetically confirmed diagnosis of NF2 Ages 5 years and above < 5/5 strength on MMT testing in at least one muscle group tested on the day of enrollment Able to follow instructions and cooperate with exam to assess strength Exclusion Criteria: No orthopedic procedure or other major surgery that could influence extremity strength in past 6 months No tibial dysplasia

Ages Eligible for Study
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Minimum Age: 5 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Cohort 1<br>Patients with NF1 | Behavioral: hand-held dynamometer<br>* 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.<br>|
| Active Comparator: Cohort 2<br>Patients with NF2 | Behavioral: hand-held dynamometer<br>* 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.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. | 1 day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. | 1 day | 
| standard error of measurement of measuring strength in the weak muscles |  | 1 day | 
| standard error of measurement of measuring strength in the dominant biceps muscle |  | 1 day |