Introduction: Objective evaluation for the Spinal Muscular Atrophy (SMA) population is often limited. Wearable sensors are a non-invasive technology to capture motions, but their application to SMA is relatively limited at this time.
Methods: Using eight 4DMotion (Allendale, NJ) sensors, patients underwent capture over 18 months as tolerated. Captures were performed in supine, sitting and standing positions as able. Retrospective comparative analysis was made for range of motion (ROM) over time regardless of age or disease type.
Results: Twenty-four patients, aged seven days of life to 18 years underwent analysis. In supine, clinically significant improvement in ROM was found at 0-12 months for R hip abduction (p-value = 0.002), L hip abduction (p-value = 0.02), and R plantarflexion (p-value = 0.05), and 0-18 months for L shoulder flexion (p-value = 0.04). In sitting, improvements were seen at 0-6 months for R hip flexion (p-value = 0.05) and R knee extension (p-value = 0.02), at 0-12 months for L cervical rotation (p-value = 0.02) and R shoulder abduction (p-value = 0.01), and 0-18 months in R shoulder flexion (p-value = 0.04), and R shoulder abduction (p-value = 0.009). ROM worsened in supine from 0-12 months for R elbow flexion (p-value = 0.009 ), R dorsiflexion (p-value = 0.03), and L dorsiflexion (p-value = 0.01). All other findings failed to reach clinical significance.
Conclusion: Wearable sensors can detect change in ROM within the SMA population, regardless of age, type or treatment intervention. Clinically significant findings suggest improvements in a progressive disease, which may be due to treatment interventions. Some findings also point to patterns of loss in more distal motions, but the influence of age or treatment type is still unclear. Nonetheless, this objective technology is proving to be an important tool for monitoring disease progression and response to ever-evolving treatments.