The extremity function index (EFI), a disability severity measure for neuromuscular diseases: psychometric evaluation

Area of Science:

• Neurology
• Rehabilitation Medicine
• Biomedical Engineering

Background:

• Neuromuscular diseases significantly impact patient function and quality of life.
• Accurate assessment of disability severity is crucial for effective management and rehabilitation.

Purpose of the Study:

• To adapt and validate the Upper Extremity Functional Index and Lower Extremity Function Scale for assessing disability in neuromuscular diseases.
• To establish the psychometric properties of the adapted scales for indicating disease severity.

Main Methods:

• A cross-sectional postal survey was conducted with 702 patients diagnosed with neuromuscular disease.
• Patients completed adapted extremity function scales and psychometric evaluation questionnaires.
• Confirmatory factor analysis, reliability, and validity tests were performed.

Main Results:

• The adapted Extremity Function Index demonstrated a two-factor structure (upper and lower extremities) with acceptable fit.
• Scales showed high internal consistency (alphas: 0.97-0.98) and good known-groups validity.
• The instrument effectively discriminated between different levels of functional limitations and quality of life.

Conclusions:

• The adapted Extremity Function Index is a valid, reliable, and easy-to-use self-report measure for disability severity in neuromuscular diseases.
• It accurately reflects daily living activities and can differentiate between disease subgroups.
• The instrument is suitable for clinical use in rehabilitation settings.