Validity and Reliability of the Neuromuscular Gross Motor Outcome

Lindsay N Alfano; Megan A Iammarino; Natalie F Reash; Brenna R Powers; Kiana Shannon; Anne M Connolly; Megan A Waldrop; Garey H Noritz; Richard Shell; Chang-Yong Tsao; Kevin M Flanigan; Jerry R Mendell; Linda P Lowes

doi:10.1016/j.pediatrneurol.2021.05.021

Validity and Reliability of the Neuromuscular Gross Motor Outcome

Pediatr Neurol. 2021 Sep:122:21-26. doi: 10.1016/j.pediatrneurol.2021.05.021. Epub 2021 Jun 8.

Affiliations

¹ The Abigail Wexner Research Institute at Nationwide Children's Hospital, Center for Gene Therapy, Columbus, Ohio; The Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio. Electronic address: lindsay.alfano@nationwidechildrens.org.
² The Abigail Wexner Research Institute at Nationwide Children's Hospital, Center for Gene Therapy, Columbus, Ohio.
³ The Abigail Wexner Research Institute at Nationwide Children's Hospital, Center for Gene Therapy, Columbus, Ohio; The Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio; The Department of Neurology, Wexner Medical Center at The Ohio State University, Columbus, Ohio.
⁴ The Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio.
⁵ The Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio; The Department of Neurology, Wexner Medical Center at The Ohio State University, Columbus, Ohio.
⁶ The Abigail Wexner Research Institute at Nationwide Children's Hospital, Center for Gene Therapy, Columbus, Ohio; The Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio.

PMID: 34271497
DOI: 10.1016/j.pediatrneurol.2021.05.021

Abstract

Background: Approved treatments in spinal muscular atrophy (SMA) have resulted in unprecedented gains for many individuals. Use of available outcomes, typically developed for a specific type of SMA, do not cover the range of progression, often resulting in a battery of functional testing being completed at visits. Our objective was to validate the Neuromuscular Gross Motor Outcome (GRO) as a tool to quantify function in SMA across the span of abilities.

Methods: Patients with genetically confirmed SMA completed functional testing at each visit including the Neuromuscular GRO and other appropriate gross motor outcomes.

Results: We enrolled 91 patients with SMA types 1 to 3 between 8 days and 32.1 years. The GRO utilizes a 0- to 2-point scale with scores in our cohort ranging from 1 to 95 points with no floor or ceiling effect. GRO scores were significantly different across functional categories (P < 0.001) and treatment status (P = 0.01) and correlated to other functional assessments (P ≤ 0.001). All patients were measured using the GRO, whereas traditional outcomes were only appropriate on 36% to 59% of our cohort.

Conclusion: The Neuromuscular GRO quantifies function across the span of age and abilities included in our cohort, allowing for continuous longitudinal monitoring on one scale to reduce the burden of testing in our heterogeneous clinic population.

Keywords: Function; Natural history; Neuromuscular GRO; Neuromuscular disease; Outcome measure; Spinal muscular atrophy; Validation.

MeSH terms

Adolescent
Adult
Child
Child, Preschool
Diagnostic Techniques, Neurological / standards*
Disease Progression*
Female
Humans
Infant
Infant, Newborn
Male
Muscular Atrophy, Spinal / diagnosis*
Muscular Atrophy, Spinal / physiopathology*
Outcome Assessment, Health Care
Reproducibility of Results
Severity of Illness Index*
Young Adult