Validity and Reliability of the Neuromuscular Gross Motor Outcome

Area of Science:

• Neurology
• Genetics
• Clinical Outcomes

Background:

• Approved spinal muscular atrophy (SMA) treatments yield significant patient gains.
• Existing outcome measures often fail to capture the full spectrum of SMA progression.
• A need exists for a comprehensive tool to assess functional abilities across SMA types.

Purpose of the Study:

• To validate the Neuromuscular Gross Motor Outcome (GRO) as a tool for quantifying function in SMA.
• To assess the GRO's ability to measure function across a wide range of SMA patient abilities and ages.
• To determine if the GRO can reduce the burden of functional testing in SMA clinics.

Main Methods:

• 91 patients with genetically confirmed SMA (types 1-3) were enrolled.
• Patients underwent functional testing, including the Neuromuscular GRO and other gross motor assessments.
• Data were collected from individuals aged 8 days to 32.1 years.

Main Results:

• The Neuromuscular GRO demonstrated a wide score range (1-95) with no floor or ceiling effects.
• GRO scores significantly differed across functional categories and treatment status.
• The GRO correlated well with other functional assessments and was applicable to 100% of the cohort, unlike traditional measures (36-59%).

Conclusions:

• The Neuromuscular GRO reliably quantifies function across diverse SMA patient ages and abilities.
• This single scale allows for continuous longitudinal monitoring, simplifying assessments.
• The GRO reduces the testing burden in heterogeneous SMA clinic populations.