Abstract:
Background and Aim: The comparability of gait analysis studies may depend on several factors, such as the length of the pathway and whether the assessment was performed with or without shoes. With disease-modifying drugs for degenerative ataxias on the horizon, these environmental changes need to be controlled in multicentre clinical trials before extracting digital performance markers. The aim of this study is to investigate the extent to which ataxia-related gait measures, which have been shown in previous studies to be sensitive to the severity of ataxia, differ between walking with and without shoes. We hypothesize that ataxic subjects will adapt their foot placement to walking without shoes, resulting in larger differences in gait compared to age-matched control subjects.
Methods: We assessed gait changes in 30 subjects with degenerative cerebellar disease (SARA: 7.2 ± 5.2, age: 49.4 ± 12.9) from three sites (Tübingen n=15, Chicago n=10, Portland n=5) and 13 age-matched healthy controls from Tübingen. Gait was quantified using 3 body-worn, inertial sensors under 2 conditions: self-paced walking 2 minutes over 10 metres (1) barefoot and (2) with shoes. Movement analysis focused on measures of spatio-temporal variability sensitive to ataxia: stride duration variability (SDcv), lateral step deviation (LSD) and toe out angle standard deviation (TOAstd). In addition, the pitch angle of the foot at initial contact (FPic) and at toe-off (FPto), the toe out angle (TOA) as well as the gait speed (GS) were examined.
Results: All foot angles and gait speed differed significantly in subjects with ataxia when walking with versus without shoes with high effect sizes (FPic r=-0.93, FPto r=-0.88, TOA r=0.69, GS r=-0.94). In addition, measures of spatio-temporal variability showed moderate effect sizes (TOAstd r=0.52, SDcv r=0.51, LSD r=0.48). Healthy controls indicated similar effects in foot pitch angles and gait speed (FPic r=-1.00, FPto r=-1.00, GS r=-0.93) but no significant change in ataxia-sensitive measures (SDcv, LSD, TOAstd). Furthermore, group analyses comparing gait measures between healthy controls and a mild cohort (n=13, SARA<7.5) revealed higher effect sizes without shoes (TOAstd: r_mild = 0.48) compared to shoes (TOAstd: r_mild = 0.34).
Conclusions: In this study, we observed a significant dependence of ataxic gait quality on foot wear. When walking without shoes, the subjects showed slower speed, less foot dorsiflexion and a greater external rotation of the feet, as well as an increase in ataxia-specific spatial-temporal variability (SDcv, LSD, TOAstd) than with shoes. Therefore, walking barefoot can increase the sensitivity of the gait examination, especially in the very early stages of the disease. However, gait measurements with shoes may be more relevant for functional ability in everyday life. Since wearing shoes significantly improves ataxia-specific parameters, patients should be advised to wear shoes for greater stability in everyday life.
