Background:
Neurofibromatosis type 1 (NF1) is a genetic condition that causes tumors to grow along the nerves in the skin, brain, and other parts of the body. People with NF1 often have pain and may experience other abnormal sensations like itching, numbness, or tingling. These symptoms can affect their daily life. Researchers want to learn more about these symptoms and find better ways to measure pain in people with NF1.
Objective:
To learn if a device called the AlgometRx Nociometer(Registered trademark) is effective in measuring pain or other abnormal sensations in people with NF1.
Eligibility:
People aged 1 year and older with NF1.
Design:
Individuals can have up to 3 assessments completed in person. Each assessment may last up to 1.0 to 1.5 hours.
Individuals will be screened. They will complete questionnaires about their health and how bad their pain is. If participants are having blood drawn for other reasons, some additional samples may be used in this study.
The AlgometRx Nociometer includes an electrode that will be placed onto a finger or a toe. The electrode will send non-painful electrical signals to activate nerves in the finger or toe. At the same time, a camera will be used to record changes in the pupil of the eye. The test will be done on all 4 of the participant s limbs; however, researchers may skip 1 or more limbs for various reasons. This test takes about 10 seconds to complete with at least a one-minute rest between testing different limbs.
Individuals will be asked to do a 2nd assessment with the AlgometRx Nociometer that may be done 1 hour later but no more than 72 hours after the first assessment. Participants who will be returning for another visit can opt to do a 3rd assessment that will be done at least 4 weeks but not more than 18 months after the 1st....
History of clinical or genetic diagnosis of NF1 as per the 2021 revised diagnostic criteria
Age >= 1 year
At least one digit (finger or toe) without open wounds for application of the device
Individuals must understand English or Spanish
History of eye pathology which precludes pupillometry, such as problems with pupillary reflex, blindness or inability to open at least one eye fully for evaluation
Individuals with chronic use of medication that specifically affects their pupillary response, such as atropine-containing eye drops
Uncontrolled intercurrent illness evaluated by medical history that would potentially increase the risk to the participant
Single group
AlgometRx Nociometer(R)
DeviceNovel objective pain measurement device
Describe the feasibility of using AlgometRx Nociometer(R) device in different age groups
Proportion of individuals who successfully complete the AlgometRx Nociometer assessment by each of the five age stratified groups (1-4, 5-7, 8-12, 13-17, 18+ years). This analysis will be performed on the Feasibility Analysis Data Set. Successful completion rate for each age group.
Describe the acceptability of the physiologic pain assessment using the AlgometRx Nociometer(R) device in different age groups
Acceptability will be described per age group for the three questions on the Acceptability Questionnaire.
Evaluate the test-retest reliability of the physiologic pain measure (Neuropathy Index)
Test-retest reliability will be measured by the intraclass correlation coefficient in participants with stable pain.
Evaluate the construct validity of the physiologic pain measure (Neuropathy Index)
Convergent and discriminant validity with the PRO/ObsRO measures will be measured through parametric (Pearson s) or nonparametric (Spearman s) tests, depending on the normality and distribution of the data.
Evaluate the physiologic pain measure (Neuropathy Index) on sensitivity to change in pain
Sensitivity to change will be measured through paired t-tests or Wilcoxon signed-rank test, depending on the normality and distribution of the data, to evaluate the statistical significance of the change in scores. We also may use standardized response means, which is a type of effect size, and one of the best methods to estimate responsiveness of measures.
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