Quantitative Gait Metrics to Assess and Predict Gross Motor Impairment in Young Children with Neurofibromatosis Type 1

/Abstract Most children with neurofibromatosis type 1 (NF1), one of the most common inherited neurological disorders in the United States, experience difficulties with large muscle movements. Current methods of measuring gross motor impairment in young children with NF1 are time- and resource-intensive, reliant on coarse scoring from a proxy typically based on the presence or absence of abilities without regard to the quality of function. These limitations hamper counseling in the clinic on the severity of gross motor difficulties, prediction of future function, and guidance on treatment planning. The objective of this K23 proposal is to develop office-based tools to quantify gait in young children with NF1 that reflect overall gross motor impairment and predict future gross motor difficulties. In this prospective observational study of ambulatory children less than six years old with NF1, we will evaluate gait speed as the fastest time to walk 10 meters and interlimb coordination derived from artificial intelligence-based pose estimates from video. We will conduct office-based gait assessments with video, clinical exams, and neurodevelopmental evaluations during routine medical visits at baseline, 12 months, and 24 months at one of the largest NF1 centers in the U.S., the NYU Comprehensive Neurofibromatosis Center. Using this design, our specific aims are to: (1) evaluate how well gait speed and interlimb coordination reflect gross motor impairment compared to currently available neurodevelopmental assessments; (2) determine the test-retest reliability of gait speed and interlimb coordination; and (3) investigate the prognostic ability of gait speed and interlimb coordination to predict gross motor impairment up to two years later. We expect these findings will result in improved developmental surveillance in clinic and inform clinical trial design with the addition of performance-based endpoints. This proposal aligns with the NINDS strategic plan of “seeing more precisely – develop and validate biomarkers and outcome measures that stimulate therapy development and improve patient care.” During this five-year award, Dr. Abreu will complete the following training goals: (1) gain fluency in advanced statistical methodologies for outcome measure development and predictive analyses; (2) deepen knowledge of clinical gait analysis; and (3) grow his skillset in pediatric NF1 clinical trial readiness. Dr. Abreu is ideally positioned to accomplish this work based upon his unique background and a stellar mentorship team, including primary mentor, Dr. Heidi Schambra (leader in quantitative motor assessment in neurological disorders), and co-mentors, Drs. Kaleb Yohay (leader in NF1) and Moriah Thomason (leader in early childhood neurodevelopment). His training program will be enriched by a scientific advisory committee with complementary expertise. This K23 award will advance Dr. Abreu towards his goal of becoming an independent physician-scientist studying quantitative motor assessment in NF1 and other pediatric neurogenetic disorders, including an R01-level submission treating gross motor impairment in early NF1. Project Number: 1K23NS146694-01 | Fiscal Year: 2026 | NIH Institute/Center: National Institute of Neurological Disorders and Stroke (NINDS) | Principal Investigator: Nicolas Abreu | Institution: NEW YORK UNIVERSITY SCHOOL OF MEDICINE, NEW YORK, NY | Award Amount: $247,995 | Activity Code: K23 | Study Section: Special Emphasis Panel[ZRG1 CN-F (91)] View on NIH RePORTER: https://reporter.nih.gov/project-details/11283030