Importance of correcting for individual differences in the clinical diagnosis of gait disorders

OBJECTIVE: To quantify the effects of subject characteristics on gait parameters using acceleration-based gait analysis. DESIGN: Cross-sectional study with a single group cohort. SETTING: Hospital setting. PARTICIPANTS: One hundred and twenty healthy subjects (six age decade groups of 10 men and 10 women) performed a 20-m walking test. METHODS: Basic gait parameters (e.g. speed) and other clinically relevant parameters (e.g. step time asymmetry) were assessed during a 20-m walking test using a tri-axial accelerometer, attached at the level of the sacrum. Subject characteristics were recorded. RESULTS: Between 34% and 51% of the variability in gait parameters was explained by age, height and gender. Subject characteristics contributed less to the variance in step time asymmetry (R(2)=0.02), gait irregularity (R(2)=0.07) and vertical displacement of the centre of mass (R(2)=0.17). Relationships identified were comparable with previous studies (e.g. faster walking speed in men, younger and taller subjects). CONCLUSIONS: Age, height and gender are determinants of basic gait parameters, while their influence on gait irregularity and step time asymmetry is minimal. This indicates that gait is variable between subjects, showing the relevance of correcting gait for subject characteristics. This study describes preliminary work to build a database of gait parameters in healthy participants, describing the effects of age, gender and height. Further studies to extend this database with patients would provide further relevance to clinical practice