Longitudinal Assessment Reveals Stage-Dependent Utility of Digital Motor Markers in SCA1.

BACKGROUND

Clinical trials in spinocerebellar ataxias (SCA) require objective, quantifiable outcome measures sensitive to changes in disease severity.

OBJECTIVES

The objective was to study the sensitivity to change of digital gait biomarkers in SCA1 over a 1-year period.

METHODS

Seventeen SCA1 patients and 15 controls walked 30 seconds wearing 3 sensors at 3 walking speeds (preferred, slow, fast) at baseline and 1-year follow-up. Relationship between gait and clinical measures was analyzed, and standardized response means (SRMs) were calculated.

RESULTS

Toe-off angle (TOA), variability in TOA, speed, and stride length showed significant responsiveness (SRM = -1.15, 0.61, -0.77, and -0.85). TOA, which correlated most strongly with ataxia severity and patient-reported outcomes, demonstrated higher sensitivity to change than Scale for Assessment and Rating of Ataxia (SARA) in early-stage disease at preferred walking speed. Gait variability measures lacked sensitivity, possibly due to the short recording period.

CONCLUSIONS

Digital gait biomarkers are promising outcomes in future clinical trials in SCA1, but their sensitivity to change appears stage dependent.