Italian validation of the SMA independence scale-upper limb module

Area of Science:

• Neurology
• Genetics
• Rehabilitation Medicine

Background:

• Spinal muscular atrophy (SMA) is a progressive genetic disorder caused by SMN1 mutations.
• Existing motor scales may not fully capture functional independence in individuals with SMA.
• There is a need for validated instruments to assess functional status across diverse SMA phenotypes.

Purpose of the Study:

• To validate the Italian SMA Independence Scale (SMAIS-ULM) for reliability and applicability.
• To assess the scale's ability to measure functional independence across different SMA types and mobility levels.
• To evaluate both patient and caregiver perspectives using the SMAIS-ULM.

Main Methods:

• A multicenter study involving patients with genetically confirmed 5qSMA.
• Data collection through 472 completed SMAIS-ULM questionnaires from patients and caregivers.
• Statistical analyses included Intraclass Correlation Coefficients (ICCs) for reliability, Kruskal-Wallis for group comparisons, and Spearman correlations with functional measures.

Main Results:

• High test-retest reliability was confirmed with ICC values ranging from 0.97 to 1.00.
• SMAIS-ULM scores significantly differed by SMA type and mobility status (walkers vs. sitters/non-sitters).
• Strong correlations with functional measures were observed, with no significant discrepancies between patient and caregiver reports.

Conclusions:

• The SMAIS-ULM is a reliable and valid instrument for measuring functional independence in individuals with SMA.
• The scale effectively differentiates functional abilities across various SMA phenotypes and mobility levels.
• SMAIS-ULM provides valuable insights from both patient and caregiver viewpoints, aiding in comprehensive assessment and care.