Related Experiment Video
Updated: Jun 19, 2026
The Multiple Sclerosis Performance Test MSPT: An iPad-Based Disability Assessment Tool
Published on: June 30, 2014
Multicenter Validation of the Charcot-Marie-Tooth Functional Outcome Measure
Melissa R Mandarakas1, Katy J Eichinger1, Paula Bray1
1From the The University of Sydney School of Health Sciences (M.R.M., P.B., K.M.D.C., M.J.M., J.B.), Faculty of Medicine and Health; Sydney Children's Hospitals Network (Randwick and Westmead) (M.R.M., P.B., K.M.C., J.B.), New South Wales, Australia; Department of Neurology (K.J.E., D.N.H.), University of Rochester, NY; Department of Neurology (M.E.S.), Carver College of Medicine, University of Iowa; Centre for Neuromuscular Diseases (M.M.R., G.M.R.), Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom; Department of Neurology (S.S.S.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; Fondazione IRCCS Istituto Neurologico Carlo Besta (D.P.), Milan, Italy; and The Children's Hospital of Philadelphia, and Perelman School of Medicine at the University of Pennsylvania (T.E.), Philadelphia.
Background And Objectives:
Charcot-Marie-Tooth disease type 1A (CMT1A), caused by a duplication of PMP22, is the most common hereditary peripheral neuropathy. For participants with CMT1A, few clinical trials have been performed; however, multiple therapies have reached an advanced stage of preclinical development. In preparation for imminent clinical trials in participants with CMT1A, we have produced a Clinical Outcome Assessment (COA), known as the CMT-Functional Outcome Measure (CMT-FOM), in accordance with the FDA Roadmap to Patient-Focused Outcome Measurement to capture the key clinical end point of function.
Methods:
Participants were recruited through CMT clinics in the United States (n = 130), the United Kingdom (n = 52), and Italy (n = 32). To derive the most accurate signal with the fewest items to identify a therapeutic response, a series of validation studies were conducted including item and factor analysis, Rasch model analysis and testing of interrater reliability, discriminative ability, and convergent validity.
Results:
A total of 214 participants aged 18-75 years with CMT1A (58% female) were included in this study. Item, factor, and Rasch analysis supported the viability of the 12-item CMT-FOM as a unidimensional interval scale of function in adults with CMT1A. The CMT-FOM covers strength, upper and lower limb function, balance, and mobility. The 0-100 point scoring system showed good overall model fit, no evidence of misfitting items, and no person misfit, and it was well targeted for adults with CMT1A exhibiting high inter-rater reliability across a range of clinical settings and evaluators. The CMT-FOM was significantly correlated with the CMT Examination Score (r = 0.643; p < 0.001) and the Overall Neuropathy Limitation Scale (r = 0.516; p < 0.001). Significantly higher CMT-FOM total scores were observed in participants self-reporting daily trips and falls, unsteady ankles, hand tremor, and hand weakness (p < 0.05).
Discussion:
The CMT-FOM is a psychometrically robust multi-item, unidimensional, disease-specific COA covering strength, upper and lower limb function, balance, and mobility to capture how participants with CMT1A function to identify therapeutic efficacy.
