Theses and Dissertations

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Browsing Theses and Dissertations by Subject "Accelerometers"

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    The measurement of stride-to-stride fluctuations in the gait of young and older adults using a body-fixed, tri-axial accelerometer.
    (Faculty of Graduate Studies and Research, University of Regina, 2012-07) Kobsar, Dylan Robert John; Barden, John; Hadjistavropoulos, Thomas; Paranjape, Raman; Wessel, Warren
    Falls represent one of the most significant health problems that affect older adults. Having the ability to accurately analyze and screen the gait of individuals who may be at risk of falling is an essential step to improving their health. Research has shown that there are numerous age-related changes in gait and that these changes may increase the risk of falling. More important than mean spatiotemporal parameters of gait, are the stride-to-stride fluctuations inherent in these measures. Both gait variability (i.e., the standard deviation of spatiotemporal gait parameters) and fractal dynamics (i.e., the patterning of fluctuations observed over a larger number of strides) can be useful in understanding the motor control of gait and predicting those who are at risk of falling. Combining this knowledge of gait variability and fractal dynamics with a simple and accurate tool could have a great impact on the effectiveness of diagnosing and treating older adults who are at risk of falling. While many devices are used to study such gait parameters, few are more intriguing than portable body-fixed, accelerometers. The small size and refined accuracy of today’s accelerometers make them excellent for analyzing gait. There is little research to confirm the validity of the accelerometer in simple mean spatiotemporal gait parameters such as stride time, and little to no research regarding more complicated measures of gait variability and fractal dynamics. The purpose of this study was to determine the validity of a body-fixed, tri-axial accelerometer in assessing mean, variability, and fractal measures of gait and to assess whether this device was sensitive enough to discriminate between healthy young and healthy older adults. Two accelerometer processing methods (e.g., vertical accelerations and anteroposterior accelerations) were compared to a criterion device (footswitch) on these measures. The accelerometer was found to be highly valid on mean temporal parameters, as well as measures of gait variability and fractal dynamics in stride times. Lower levels of validity were observed in measures of gait variability and fractal dynamics in step times, with the anteroposterior method displaying a slight advantage over the vertical method. Nevertheless, both accelerometer methods, along with the footswitch, found older adults displayed significantly lower fractal scaling than younger adults, suggesting a more random gait pattern and a declining motor control of gait. This study supports the tri-axial accelerometer for gait analysis in older adults and those who may be at risk of falling, but cautions against the use of gait variability in combined step times.