Body Weight Support Harness System in Spinal Muscular Atrophy

Exploring the Feasibility and Utility of In-home Body Weight Support Harness System Use in Children Treated for Spinal Muscular Atrophy: a Pilot Study

The goal of this pilot interventional study is to learn about the use of an in-home harness system in children who have been treated for spinal muscular atrophy. The main questions it aims to answer are: Is the in-home body weight support harness system a feasible option for families to use? Is the in-home body weight support harness system a useful tool for children treated for spinal muscular atrophy? Is the in-home body weight support harness system a safe tool for children treated for spinal muscular atrophy? Participants will be given an in-home body weight support harness system and taught how to use it. Families will document how often and for how long they use the system over 6 months. Children will be given tests of motor function at the beginning, 3-months, and 6-months. At the end of the study, families will be asked to fill out a questionnaire about thier experience using the system.

All participants will be entered into treatment arm and receive an in-home body weight support harness system

A portable, adjustable body weight support harness system that occupies roughly 9 feet x 9 feet space in the home. The system allows 360 degrees of mobility anywhere within the footprint of the frame. The amount of body weight support is adjustable.

A five question likert-style survey asking families to rate their experience during the study. The scales asks the family to rate (1) the perceived impact of BWSS on motor and (2) non-motor skills, (3) the child's perceived enjoyment using the system, (4) the ease of equipment use, and (5) if the family believed that use of the BWSS was beneficial on a 5-point Likert scale; scores of 4 or 5 were considered favorable, scores of 3 were considered neutral, and scores of 1 or 2 were considered unfavorable. Higher scores indicate greater perceived benefit of participation.

A 50-item performance-based outcome developed to quantify motor function across the span of age and abilities in individuals with neuromuscular disorders including spinal muscular atrophy (SMA). Scores range from 0 - 100 points; higher scores reflect a greater level of function. An increase in score indicates a better outcome.

A disease-specific and performance-based outcomes originally developed to measure motor skill in untreated individuals with SMA. Scores range from 0 - 66 points; higher scores reflect a greater level of function. An increase in score indicates a better outcome.

A disease-specific and performance-based outcomes originally developed to measure motor skill in untreated individuals with SMA, revised following Rasch analysis of HFMSE. Scores range from 0 - 69 points; higher scores reflect a greater level of function. An increase in score indicates a better outcome.

A norm-referenced developmental assessment of gross motor skill in children 16 days - 3.5 years of age. Raw scores range from 0 - 72. Higher scores indicate a greater level of funcion. An increase in score indicates a better outcome.

A checklist of key gross motor milestones expected during typical development. Scores can range from 0 - 6 milestones achieved. Achievement of a greater number of milestones indicates better outcomes.

A log to document frequency (each use) and duration (how long it was used at one time) of harness system use.

Inclusion Criteria: Confirmed heterozygous mutation in SMN1 gene and 2 or 3 copies of SMN2 (historically, SMA Type 1 and Type 2) Past or current treatment with nusinersen, onasemnogene abeparvovec, or risdiplam Upright head control (defined as the ability to lift head from full forward flexion) Weight under or 50lbs Confirmed motor delay Exclusion Criteria: 4+ copies of SMN2 (historically, SMA Type 3 and 4) Evidence of lower limb injury or recent fracture In the opinion of the investigator, it was unsafe for the child to participate

Participant data will be provided in summary form at manuscript submission. Certain individual participant data will be available in manuscript as well.