Correlation of GAITRite Walkway System and Biodex Balance System Measures to the FARS Score in Friedreich's Ataxia Patients: A Validation Study

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Objective: To test the validity of the GAITRite Walkway System and Biodex Balance System for measuring parameters of neurological dysfunction in Friedreich’s Ataxia (FA) patients against the standard of the Friedreich’s Ataxia Rating Scale (FARS).

Background: FA is a neurodegenerative disease causing ataxia and cardiomyopathy. Precise measures are needed to test disease progression in FA in clinical trials. The GAITRite Walkway System and the Biodex Balance System are quantitative measures that evaluate gait and balance dysfunction using computerized technology.

Design/Methods: In this prospective, longitudinal study, ambulatory FA patients were examined at baseline, and at 6, 12, and 24 months using the GAITRite and Biodex Systems and the FARS. Healthy, matched controls were tested at baseline and 12 months. All analyses were carried out using SAS 9.4.

Results: Eight FA patients and 8 controls were included in this analysis. The following GAITRite parameters correlated significantly with the total FARS score in FA patients; comfortable walking velocity (r=-0.536; p<0.002), comfortable walking cadence (r=-0.573; p<0.001), comfortable step length (r=-0.358; p=0.044), comfortable stride length (r=-0.358; p=0.044), and comfortable footwidth (r=-0.420; p=0.017). The following Biodex measures correlated significantly with the FARS score: Overall Stability Index with eyes open (EO) and eyes closed (EC) (r=0.825; p<0.0001 and r=0.495; p<0.0039), Anterior/Posterior Stability Index, EO (r=0.726; p<0.0001), and Medial/Lateral Stability Index, EO and EC (r=0.728; p<0.0001; r=0.654; p<0.0001). The control group had corresponding zero or near zero scores for one or more measures, and we were unable to assess the validity of these tests in this group.

Conclusions: In this study, multiple GAITRite and Biodex measures correlated significantly with the FARS scores, suggesting a high degree of clinical significance and providing evidence for validation of these measures in FA patients.


American Academy of Neurology Annual Meeting (AAN)


Washington, DC